5-Hydroxymethylfurfural (HMF) and its oxidation derivatives have emerged as a bridge between biomass resources and the future energy industry. These renewable biomass resources can be transformed into a variety of value-added chemicals, thereby addressing the challenges posed by diminishing fossil fuel reserves and environmental concerns. The immobilization of catalysts represents an innovative method for the sustainable and efficient synthesis of HMF and its oxidation derivatives. This method not only enhances the yield and selectivity of the products but also allows for the optimization of the catalytic performance of immobilized catalysts through the strategic design of their supports. In this review, we provide an overview of the recent advancements in the technology of immobilized catalyst and its application in the synthesis of HMF and its oxidation derivatives, with a particular focus on the preparation and catalytic characteristics of these immobilized catalysts. Furthermore, we discuss potential future directions for the development of immobilized catalysts, including the preparation of high-performance immobilized catalysts, the exploration of their growth and catalytic mechanisms, and the economic implications of raw material utilization. This area of research presents both significant promise and considerable challenges.

Humins, as a group of by-products formed through the condensation and coupling of fragment intermediates during lignocellulosic biomass refining, can cause numerous negative effects such as the wastage of carbon resources, clogging of reactor piping, deactivation of catalyst, and barriers to product separation. Elucidating the generation mechanism of humins, developing efficient inhibitors, and even utilizing them as a resource, both from the perspective of atom economy and safe production, constitutes a research endeavor replete with challenges and opportunities. Orbiting the critical issue of humins structure and its generation mechanism from cellulose and hemicellulose resources, the random condensation between intermediates such as 5-hydroxymethylfurfural, furfural, 2,5-dioxo-6-hydroxyhexanal, and 1,2,4-benzenetriol etc. were systematically summarized. Additionally, the presence of lignin in real biorefining processes further promotes the formation of a special type of humins known as "pseudo-lignin". The influences of various factors, including raw materials, reaction temperature and time, acid-base environment, as well as solvent systems and catalysts, on the formation of humins were comprehensively analyzed. To minimize the formation of humins, the design of efficient solvent systems and catalysts is crucial. Furthermore, this review investigates the approaches to value-added applications of humins. The corresponding summary could provide guidance for the development of the humins chemistry.

Current ever-accumulating plastic waste can be considered a significant carbon resource for energy conversion and chemical production. The development of new approaches for upcycling plastic waste through chemical degradation may enable circularity and promote closed-loop recycling of carbon sources compared to traditional recycling methods. Zeolite, a widely used solid acid catalyst with high industrial potential in petroleum and biomass refining, has been extensively studied for its role in transforming plastics. In this review, we present an overview of zeolite-based catalytic systems for the chemical recycling of plastic waste and discuss how zeolites could potentially contribute to the future development of a circular economy. To provide a comprehensive understanding, we begin with a brief introduction to zeolites, analyzing their key features and exploring their opportunities as well as challenges in processing plastic waste. Subsequently, we delve into the chemistry of catalytic cracking and tandem catalysis using zeolite-based catalysts on plastics. Overall, we emphasize the importance of intelligent catalyst design and lower-energy pathways to incentivize plastic upcycling while alleviating the burden caused by waste plastics.

Photocatalysis is an important process in energy conversion and environmental usage because of its feasible, profitable, and environmentally safe benefits. Coordination chemistry of the CeO₂ is gaining significant interest because its nanocomposites show unique characteristics namely optically active, wide bandgap (E_g), reversible valence states (Ce^3+/4+), rich defect architectures, high O₂ storage capability, ionic conductivity, and exceptional chemical resistance. Systematically summarized the importance of synthesis methods, particle morphology, and crystal structure aiming at how to heighten the efficacy of CeO₂-derived hybrid heterojunction (HHJ) photocatalyst. Selection of an appropriate synthesis method and morphology of the composite materials are beneficial in inhibiting the rapid electron-hole (e⁻-h⁺) recombination, improvement in visible light adsorption, and large generation of e⁻-h⁺ pairs to accelerate the photocatalysts activities. Various modification approaches include elemental doping (metal/non-metal doping), heterojunction construction (lower/wide E_g semiconductors (SCD), carbon, conducting polymeric materials), imperfection engineering, and multicomponent hybrid composites. These methods assist as a valuable resource for the rational design of effective CeO₂-based composite photocatalysts for sustainable development owing to the enhancement of oxygen species mobility, rapid charge transfer, maximum visible light captivation and slow down the charge recombination rate with increase photogeneration of e⁻-h⁺ pairs. Also examines the advancements made in CeO₂ conjugated hybrid composites in photo-oxidation of wastewater effluents (antibiotic/organic dyes/chemical/pharmaceutical), heavy metal removal, H₂ production, CO₂ reduction, and H₂O splitting applications. Subsequently, the difficulties and fundamental ideas behind several heterojunction photocatalysts encountered by CeO₂-based composites are examined, and future directions for their development are suggested.

The assembly of different Metal organic framework (MOFs) into hybrid heterostructures has proven to be a promising strategy that can effectively break through the limited regulatory capacity of single metal sites. Here, an S-scheme heterostructure (Fe₃Ni-MOF) based on homologous ligands (1,4-phthalic acid) of ultra-thin Ni-MOF and Fe-MOF nanoparticles with directional electron transport channels, was developed and used it for photoreduction of CO₂. Under the S-scheme electric field mechanism, the photogenerated carrier can achieve efficient directional separation through Fe-O-Ni atomic bond, which significantly reduces the energy barrier of the rate-determining step. Results show that the performance of Fe₃Ni-MOF (63.5 μmol g^-1) was 20 and 3.2 times higher than that of Ni-MOF and Fe-MOF, respectively, and exhibits excellent CO selectivity (96.4%) and stability. Transmission electron microscopy and atomic force microscopy revealed the two-molecular-layers structure of Ni-MOF and the micro-assembly structure of Fe₃Ni-MOF, which can shorten the electron transport distance and increase the molecular mass transfer rate. X-ray photoelectron spectroscopy, electron spin resonance and electron density difference calculations reveal that interfacial electric fields and atomic bonds work together to promote directional carrier separation, resulting in the accumulation of holes on Ni-MOF and electrons on Fe-MOF. The Gibbs free energy calculation and in-situ Fourier transformed infrared spectroscopy validate that the micro-assembled S-scheme heterostructures with directional electron transport channels can significantly reduce the activation energy barrier of the reaction. This study not only proves the feasibility of constructing MOFs S-scheme heterostructures using homologous ligands, but also provides a new way to overcome the limitations of monometallic MOFs. This strategy is expected to open up a new avenue to design efficient photocatalysts.

Electrochemical carbon dioxide reduction reaction (CO₂RR) produces valuable chemicals by consuming gaseous CO₂ as well as protons from the electrolyte. Protons, produced by water dissociation in alkaline electrolyte, are critical for the reaction kinetics which involves multiple proton coupled electron transfer steps. Herein, we demonstrate that the two key steps (CO₂-*COOH and *CO-*COH) efficiency can be precisely tuned by introducing proper amount of water dissociation center, i.e., Fe single atoms, locally surrounding the Cu catalysts. In alkaline electrolyte, the Faradaic efficiency (FE) of multi-carbon (C₂₊) products exhibited a volcano type plot depending on the density of water dissociation center. A maximum FE for C₂₊ products of 73.2% could be reached on Cu nanoparticles supported on N-doped Carbon nanofibers with moderate Fe single atom sites, at a current density of 300 mA cm^-2. Experimental and theoretical calculation results reveal that the Fe sites facilitate water dissociation kinetics, and the locally generated protons contribute significantly to the CO₂ activation and *CO protonation process. On the one hand, in-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (in-situ ATR-SEIRAS) clearly shows that the *COOH intermediate can be observed at a lower potential. This phenomenon fully demonstrates that the optimized local water dissociation kinetics has a unique advantage in guiding the hydrogenation reaction pathway of CO₂ molecules and can effectively reduce the reaction energy barrier. On the other hand, abundant *CO and *COH intermediates create favorable conditions for the asymmetric *CO-*COH coupling, significantly increasing the selectivity of the reaction for C₂₊ products and providing strong support for the efficient conversion of related reactions to the target products. This work provides a promising strategy for the design of a dual sites catalyst to achieve high FE of C₂₊ products through the optimized local water dissociation kinetics.

The p-block metal (In, Sn, Bi, etc.)-based electrocatalysts have exhibited excellent activity in the electrocatalytic CO₂ reduction (ECR) to formate. However, the rapid decrease in catalytic activity caused by catalyst reconstruction and agglomeration under ECR conditions significantly restricts their practical applications. Herein, we developed a sulfur anchoring strategy to stabilize the high-density sub-3 nm In₂S₃ nanoparticles on sulfur-doped porous carbon substrates (i-In₂S₃/S-C) for formate production. Systematic characterizations evidenced that the as-prepared catalyst exhibited a strong metal sulfide-support interaction (MSSI), which effectively regulated the electronic states of In₂S₃, achieving a high formate Faradaic efficiency of 91% at −0.95 V vs. RHE. More importantly, the sulfur anchoring effectively immobilized the sub-3 nm In₂S₃ nanoparticles to prevent them from agglomeration. It enabled the catalysts to exhibit much higher durability than the In₂S₃ samples without sulfur anchoring, demonstrating that the strong MSSI and fast charge transfer on the catalytic interface could significantly promote the structural stability of In₂S₃ catalysts. These results provide a viable approach for developing efficient and stable electrocatalysts for CO₂ reduction.

Fe-based catalysts are widely used for CO₂ hydrogenation to light olefins (C_2-4⁼); however, precise regulation of active phases and the balance between intermediate reactions remain significant challenges. Herein, we find that the addition of moderate amounts of Ti forms a strong interaction with Fe compositions, modulating the Fe₃O₄ and Fe₅C₂ contents. Enhanced interaction leads to an increased Fe₅C₂/Fe₃O₄ ratio, which in turn enhances the adsorption of reactants and intermediates, promoting CO hydrogenation to unsaturated alkyl groups and facilitating C-C coupling. Furthermore, the strong Fe-Ti interaction induces the preferential growth of Fe₅C₂ into prismatic structures that expose the (020), (-112), and (311) facets, forming compact active interfacial sites with Fe₃O₄ nanoparticles. These facet and interfacial effects significantly promote the synergistic coupling of the reverse water gas shift and Fischer-Tropsch reactions. The optimized 3K/FeTi catalyst with the highest Fe₅C₂/Fe₃O₄ ratio of 3.6 achieves a 52.2% CO₂ conversion rate, with 44.5% selectivity for C_2-4⁼ and 9.5% for CO, and the highest space-time yield of 412.0 mg g_cat^-1 h^-1 for C_2-4⁼.

The selective activation of C-H bonds is pivotal in catalysis for converting hydrocarbons into value-added chemicals. Ethylbenzene dehydrogenation to styrene is crucial process to produce polystyrene and its derivatives used in synthetic materials. Herein, K-Cr@Y with zeolite-encaged isolated O=Cr(VI)=O species modified by extraframework potassium ions is constructed, showing remarkable performance in CO₂-promoted ethylbenzene dehydrogenation with initial ethylbenzene conversion of 66% and styrene selectivity of 96%, outperforming other M-Cr@Y catalysts (M = Li, Na, Rb, Cs). Extraframework potassium ions can modulate the electron density of zeolite-encaged Cr(VI) species and therefore facilitate C-H bond activation in ethylbenzene molecules. The gradual reduction of zeolite-encaged O=Cr(VI)=O to less active Cr(IV)=O species by dihydrogen during ethylbenzene dehydrogenation is evidenced by comprehensive characterization results, and Cr(IV)=O can be re-oxidized to O=Cr(VI)=O species upon simple calcination regeneration. The results from in situ DRIFT spectroscopy elucidate the critical promotion role of CO₂ in ethylbenzene dehydrogenation over K-Cr@Y by retarding the over-reduction of zeolite-encaged Cr species to inactive Cr(III) species and suppressing coke deposition. This study advances the rational design of non-noble metal catalysts for CO₂-promoted ethylbenzene dehydrogenation with zeolite-encaged high valence transition metal ions modulated by extraframework cations.

In the methanol-to-hydrocarbons (MTH) process, C1 species, including methanol, dimethyl ether, and surface methoxy species (SMS), play crucial roles in the evolution of organic species and the construction of reaction networks. Understanding the roles of C1 species throughout the entire MTH process is both essential and challenging. Herein, the dynamic evolution of organic species and unique variation of C1 species during the real-time MTH process were observed by operando diffused reflectance Fourier transform infrared spectroscopy and ex-situ ¹³C cross polarization/magic-angle spinning nuclear magnetic resonance experiments. Importantly, density functional theory calculations thoroughly illustrated that methanol and SMS serve as key C1 species, in the form of not only methylation agents but also hydride acceptors, and their contributions vary across different reaction periods. Initially, SMS acts as the preferential C1 surface intermediate, methylating with hydrocarbons to propagate C-C bond, while also accepting hydrides to generate precursors for active hydrocarbon pool species. As reaction progresses, the role of SMS gradually diminishes, and thereby methanol becomes the predominant C1 species, in methylation for efficient product formation, meanwhile in hydride-transfer causing catalyst deactivation. Additionally, it was demonstrated that the confined zeolite microenvironment modified by large organics affects methanol adsorption and SMS formation, also accounting for the absence of SMS during the later period of reaction. This work provides a comprehensive and systematic understanding of the dynamic roles of C1 species throughout the MTH process, beyond the role as reactants.

The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis, yet it remains a grand challenge in selectivity and activity control. Herein, we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H₂ as the reductant. Ir-promoted Fe⁰@Fe₅C₂ gave the best performance among the investigated catalysts, and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls, with the yield up to 85%. In addition, in the presence of alkenes, three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules. The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C-O bond activation after carbonization, respectively. This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.

Hydrocracking technology represents a crucial position in the conversion of heavy oil and the transformation development from oil refining to the chemical industry. The properties of catalysts are one of the key factors in the hydrocracking process. As the main acidic component of hydrocracking catalyst, the influence of zeolite properties on the reaction performance has been the focus of research. In this study, a series of NiMo/Al₂O₃-Y catalysts were prepared using different Y zeolites as acidic components, and their performances in the hydrocracking of n-C₁₀ were also evaluated. The structure-activity relationship between Y zeolite and the cracking performance of n-C₁₀ was investigated with machine learning. First, a database of the physical and chemical properties of Y zeolite and their performance was established, and the correlation analysis was also conducted. Parameters such as the cell constant, acid content, acid strength, B/L ratio, mesopore volume, micropore volume of Y zeolite, and the reaction temperature were selected as independent variables. The conversion of n-C₁₀ and the ratios of products C₃/C₇ and i-C₄/n-C₄ were selected as dependent variables. A model was established by the random forest algorithm and a new zeolite was predicted based on it. The results of model prediction were in good agreement with the experimental results. The R² of the n-C₁₀ conversion, C₃/C₇ ratio, and i-C₄/n-C₄ ratio were 0.9866, 0.9845, and 0.9922, and the minimum root mean square error values were 0.0163, 0.101, and 0.0211, respectively. These results can provide reference for the development of high performance hydrocracking catalyst and technology.

High-entropy alloy (HEA) offer tunable composition and surface structures, enabling the creation of novel active sites that enhance catalytic performance in renewable energy application. However, the inherent surface complexity and tendency for elemental segregation, which results in discrepancies between bulk and surface compositions, pose challenges for direct investigation via density functional theory. To address this, Monte Carlo simulations combined with molecular dynamics were employed to model surface segregation across a broad range of elements, including Cu, Ag, Au, Pt, Pd, and Al. The analysis revealed a trend in surface segregation propensity following the order Ag > Au > Al > Cu > Pd > Pt. To capture the correlation between surface site characteristics and the free energy of multi-dentate CO₂ reduction intermediates, a graph neural network was designed, where adsorbates were transformed into pseudo-atoms at their centers of mass. This model achieved mean absolute errors of 0.08-0.15 eV for the free energies of C₂ intermediates, enabling precise site activity quantification. Results indicated that increasing the concentration of Cu, Ag, and Al significantly boosts activity for CO and C₂ formation, whereas Au, Pd, and Pt exhibit negative effects. By screening stable composition space, promising HEA bulk compositions for CO, HCOOH, and C₂ products were predicted, offering superior catalytic activity compared to pure Cu catalysts.

Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods, which exhibit unique properties such as suppressing structure-sensitive side reactions. However, this method is limited by the use of different metal precursor salts corresponding to different ligands. An alternative approach, the ion exchange (IE) method, can overcome this limitation to some extent. Nevertheless, there is still an urgent need to address the stabilization of metals (especially precious metals) by using IE method. Here, we reported a Pt cluster catalyst prepared mainly by anchoring Pt atoms via O located near the framework Zn in zincosilicate zeolites and riveted by zeolite surface rings after reduction (reduced Pt/Zn-3-IE). The catalyst can achieve an initial propane conversion of 26% in a pure propane atmosphere at 550 °C and shows little deactivation even after 7.5 d of operation. Moreover, the alteration of catalyst by the introduction of framework Zn was also highlighted and interpreted.

In our previous study, the activity and stability of the Mo/HZSM-5 catalyst were enhanced by mixing physically with NiO in methane dehydroaromatization (MDA) reaction. It has been confirmed that the physically mixed NiO not only promoted the dispersion of MoC_x active sites but also reduced the coke formation on the MoC_x owing to the CNTs growth on Ni. However, the promotional effect of NiO was limited when the particle size was reduced, due to the excessive interaction with MoO_x (forming NiMoO₄) which is detrimental to the MoC_x dispersion. In this study, to overcome the limitation, silica shell on NiO particles with various sizes (5, 15, 110 nm) was introduced. The catalyst with silica shell coated NiO with the size of 15 nm exhibited a significant improvement in both BTX yield and stability, and the catalyst with silica shell coated NiO with the size of 5 nm achieved the highest maximum BTX yield, about 7.2%. This study demonstrates that the catalytic performance improved as the NiO particle size decreased with the introduction of the silica shell. Combined transmission electron microscopy-energy dispersive spectroscopy, X-ray diffraction, temperature-programmed surface reaction of methane, CO chemisorption, visible Raman, and thermogravimetric analysis allowed us to confirm that a thin silica shell further enhances the MoC_x dispersion while preventing the formation of Ni-Mo complexes. However, when the size of NiO decreased to 5 nm, CNT growth on Ni was limited during the reaction, which is crucial for reducing coke formation on Mo active sites, thereby resulting in the decreased catalyst stabilization ability of Ni. Overall, this study indicates that the introduction of a silica shell in a controlled way can significantly enhance the promotional effect of physically mixed NiO on MDA.

Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges. In this report, we present a highly efficient MXene-based photocatalyst, which is combined with MoS₂ nano patches and TiO₂/Ti₃C₂ (TTC) nanowires through hydrothermal treatment. Of all the composites tested, the optimized photocatalyst gave a remarkable H₂ and revolving polylactic acid (PLA) into pyruvic acid (PA). Achieving a remarkable H₂ evolution rate of 637.1 and 243.2 μmol g⁻¹ h⁻¹, in the presence of TEOA and PLA as a sacrificial reagent under UV-vis (λ ≥ 365 nm) light irradiation. The improved photocatalytic activity is a result of the combination of dual cocatalyst on the surface of TTC photocatalyst, which create an ideal synergistic effect for the generation of PA and the production of H₂ simultaneously. The MoS₂TiO₂/Ti₃C₂ (MTT) composite can generate more photoexcited charge carriers, leading to the generation of more active radicals, which may enhance the system's photocatalytic activity. This work aims at demonstrating its future significance and guide the scientific community towards a more efficient approach to commercializing H₂ through photocatalysis.

Methane, the primary constituent of natural gas, shale gas, and flammable ice, serves as a crucial carbon-based energy source and chemical feedstock. Traditional gas reserves are universally acknowledged as limited and non-renewable resources over an extended timespan stretching from decades to millennia. Biomethane, with its unique renewable properties, showcases remarkable development potential and presents a compelling supplement and even alternative for fossil fuel. Although catalytic hydrothermal processes appear as promising valorization routes to transfer biomass to sustainable methane, the safety and supply source of high-pressure hydrogen remain key factors restricting the widespread application. Herein, a catalytic approach without an external hydrogen source was developed to transform waste biomass resources into CH₄ under the Ni-Mo catalyst. The total carbon yield of gas products reached up to 92.2%, of which the yield of methane and C₂-C₄ hydrocarbons were 44.9% and 3.0%, respectively. And it’s calculated that approximately 343.6 liters of CH₄ could potentially be generated from 1 kilogram of raw biomass. Ni-based catalysts exhibited the robust activity in cleaving C-C and C-O bonds. And the introduction of an appropriate amount of molybdenum significantly enhanced catalytic performance of reforming and subsequent methanation reaction, likely due to the high adsorption capacity of highly dispersed Ni-Mo catalysts for carbon monoxide and hydrogen molecules, facilitating the methanation reaction. The pathway of catalytic methane production might be inferred that CO, H₂ and a large number of oxygen-containing intermediates were formed via decarbonylation, dehydrogenation, and retro-aldol condensation reaction under hydrothermal condition. These intermediates then underwent the reforming reaction to generate H₂ and CO₂, ultimately forming CH₄ through the methanation reaction.

The efficient hydrogenolysis of esters to alkanes is the key protocol for producing advanced biofuels from renewable plant oils or fats. Due to the low reactivity of the carbonyl group in esters, a high reaction temperature (>250 °C) is the prerequisite to ensure high conversion of esters. Here, we report a highly dispersed MoO_x-Ru/C bimetallic catalyst for the efficient hydrogenolysis of esters to alkanes under 150 °C. The optimal catalyst exhibits >99% conversion of methyl stearate and 99% selectivity to diesel-range alkanes, reaching a high rate of up to 2.0 mmol g_cat^-1 h^-1, 5 times higher than that of Ru/C catalyst (MoO_x/C is inert). Integrated experimental and theoretical investigations attribute the high performance to the abundant MoO_x-Ru interfacial sites on the catalyst surface, which offers high activity for the C-O cleavage of esters. Furthermore, the dispersed MoO_x species significantly weaken the hydrocracking activity of the metallic Ru for C-C bonds, thus yielding alkane products without carbon loss. This study provides a facile and novel strategy for the design of high-performance heterogeneous catalysts for the hydrodeoxygenation of biomass-derived esters to alkane products.

Development of efficient and stable metal catalysts for the selective aqueous phase hydrodeoxygenation (HDO) of biomass-derived oxygenates to value-added biofuels is highly desired. An innovative surface microenvironment modulation strategy was used to construct the nitrogen-doped hollow carbon sphere encapsulated with Pd (Pd@NHCS-X, X: 600-800) nanoreactors for catalytic HDO of biomass-derived vanillin in water. The specific surface microenvironments of Pd@NHCS catalysts including the electronic property of active Pd centers and the surface wettability and porous structure of NHCS supports could be well-controlled by the calcination temperature of catalysts. Intrinsic kinetic evaluations demonstrated that the Pd@NHCS-600 catalyst presented a high turnover frequency of 337.77 h^-1 and a low apparent activation energy of 18.63 kJ/mol. The excellent catalytic HDO performance was attributed to the unique surface microenvironment of Pd@NHCS catalyst based on structure-performance relationship analysis and DFT calculations. It revealed that pyridinic N species dominated the electronic property regulation of Pd sites through electronic metal-support interaction (EMSI) and produced numerous electron-rich active Pd centers, which not only intensified the dissociation and activation of H₂ molecules, but also substantially improved the activation capability of vanillin via the enhanced adsorption of -C=O group. The fine hydrophilicity and abundant porous structure promoted the uniform dispersion of catalyst and ensured the effective access of reactants to catalytic active centers in water. Additionally, the Pd@NHCS-600 catalyst exhibited excellent catalytic stability and broad substrate applicability for the selective aqueous phase HDO of various biomass-derived carbonyl compounds. The proposed surface microenvironment modulation strategy will provide a new consideration for the rational design of high- performance nitrogen-doped carbon-supported metal catalysts for catalytic biomass transformation.

The efficient conversion of lignin into mono-cycloalkanes via both C-O and C-C bonds cleavage are attractive, but challenging due to the high C-C bond dissociation energy. Previous studies have demonstrated that NbO_x-based catalysts exhibited exceptional capabilities for C_Ar-C bond cleavage and broken the limitation of lignin monomers. In this work, we presented an economical multifunctional Pt-Nb/MOR catalyst that achieved an impressive monomer yield of 147% during the depolymerization and hydrodeoxygenation of lignin into mono-cycloalkanes. Reaction pathway studies showed that unlike traditional NbO_x-based catalytic system, bicyclohexane was an important intermediate in this system and followed the C_sp3-C_sp3 cleavage pathway after complete cyclic-hydrogenation. Deep investigations demonstrated that the doping of Nb in Pt/MOR not only enhanced the activation of hydrogen by Pt, but also increased the acidity of MOR, both of these are favor for the hydrogenolytic cleavage of C_sp3-C_sp3 bonds. This work provides a low-cost catalyst to obtain high-yield monomers from lignin under relatively mild conditions and would help to design catalysts with higher activity for the valorization of lignin.

The catalytic synthesis of 1,3-butadiene (1,3-BD) from bio-based ethanol offers an alternative and sustainable process beyond petroleum. However, the intrinsic active sites and corresponding mechanism of 1,3-BD formation have not been fully elucidated yet. By correlating systematic characterization results with catalytic performance, the open Zr species, i.e., Zr(OH)(OSi)₃ moieties, were identified as the active site over the Zr/MFI-BM catalysts for the catalytic transformation of ethanol-acetaldehyde into 1,3-BD. In conjunction with controlled experiments and theory calculations, ethanol and acetaldehyde are proposed to synergistically co-adsorb on the Zr(OH)(OSi)₃ species in a bi-molecular mode, which assists the acetaldehyde condensation and accelerates the critical Meerwein-Ponndorf-Verley-Oppenauer reduction, and accordingly promotes 1,3-BD formation. These findings will stimulate the search towards new metal-zeolite combinations for efficient production of value-added 1,3-BD via biomass-derived ethanol and beyond.

Precisely tailoring metal single-atoms within zeolite scattfolds and understanding the origin of the unique behavior of such atomically dispersed catalysts are pivotal and challenge in chemistry and catalysis. Herein, we have successfully fabricated Ni single-atoms within BEA zeolite (Ni₁@Beta) through a facile in situ two-step hydrothermal strategy, notably without using any chelating agent for stabilizing Ni species. With the aid of advanced characterization techniques, such as aberration-corrected high-angle annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, etc., and combined with density functional theory calculations, the nature and micro-environment of isolated Ni species, which are incorporated within 6-membered rings and stabilized by four skeletal oxygens of Beta zeolite, have been identified. The as-obtained Ni₁@Beta exhibits a superior performance in terms of activity (with a turnover frequency value up to 114.1 h^-1) and stability (for 5 consecutive runs) in the selective hydrogenation of furfural, surpassing those of Ni nanoparticle analogues and previously reported Ni-based heterogeneous catalysts. This study provides an efficient strategy for the fabrication of non-noble metal single-atoms within zeolites, which could be of great help for the design of metal-zeolite combinations in the chemoselective reactions involved in biomass conversion and beyond.

Sulfide photocatalysts are one of the widely recognized excellent photocatalysts. However, the stability of sulfide photocatalysts has always been a challenging problem in the field of photocatalysis. Herein, an in-situ oxidation strategy was designed to construct ZnO/ZnS homologous S-scheme catalysts and solve its poor stability problem. The results indicates that the obtained ZnO/ZnS homologous heterojunction not only has dual-function performance, but also has good recover ability in photocatalytic performance: the photocatalytic H₂O₂ yield can reach 517.32 μmol g^-1 (in pure water) after two hours, the photocatalytic H₂ yield is 140.45 mmol g^-1 in 5 h, which were 2.2 times and 84 times than that of the ZnS, respectively. Excitingly, the recovery rate of photocatalytic performance can be increased from 33.3% to 97.2%. The excellent photocatalytic performance is attributed to that the obtained homologous heterojunction can not only broaden the light absorption capacity (370-600 nm), but also facilitate the separation and transfer of photogenerated electrons. The high recovery rate of photocatalytic stability is due to the re-generation of zinc oxide in the oxidation process, which makes the photocatalyst return to the original homologous heterojunction structure. Meanwhile, experimental results, density functional theory calculations and Kelvin probe force microscopy indicate that the photo-induced carrier transfer pathway follows the S-scheme heterojunction mechanism. This work provides new ideas and breakthroughs for the design and construction of sulfide photocatalysts with excellent photocatalytic stability.

Nitrogen oxides (NO_x) present in flue gas are economically renewable N1 resources. Unlike traditional selective catalytic reduction processes that convert NO into N₂, redirecting NO towards the synthesis of value-added NH₃ offers significant practical benefits. In this study, a Ti-based metal-organic framework (Ti-MOF), specifically MIL-125, was utilized as a support for Fe, which was subsequently calcined at 400 °C to produce a Fe₂O₃/TiO₂-MOF catalyst. The resulting catalyst demonstrated exceptional performance, achieving 99% NO conversion and 95% NH₃ selectivity under optimal conditions of 450 °C, 0.1 MPa, and a gas hourly space velocity of 38000 mL g^-1 h⁻¹. Additionally, the catalyst exhibited excellent stability and resistance to water and sulfur. The high efficiency of Fe₂O₃/TiO₂-MOF is attributed to the abundance of Fe²⁺ sites at the reaction temperature, which enhances NO adsorption and activation. Furthermore, density functional theory calculations suggest that NO undergoes hydrogenation at the N-terminus on the Fe₂O₃/TiO₂-MOF surface, leading directly to NH₃ synthesis rather than dissociation followed by hydrogenation. This catalyst presents a novel approach for converting NO_x into high-value chemical products.

Seawater electrolysis holds significant importance for advancing clean energy conversion. NiFe-based catalysts exhibit outstanding performance in the oxygen evolution reaction (OER) under alkaline conditions. However, the instability of the Fe active center leads to leakage issues, hindering further development in the field of seawater electrolysis. Here, we adopt an element doping engineering strategy to enhance the OER activity of Ni-Fe oxyhydroxides and greatly stabilize the Fe sites by meticulously optimizing the d-band centers. Among the selected metals (Al, Ce, Co, Cr, Cu, Mn, Sn, Zn and Zr), Mn doping is the most effective as confirmed by both theoretical calculations and experimental verifications. The NiFeMn-OOH/NF formed in situ from the corresponding metal-organic framework requires only 217 mV to achieve a current density of 10 mA·cm^-2 in alkaline seawater, and exhibits exceptional stability. Theoretical calculations uncover that the Fe sites exhibit better balance of adsorption-desorption kinetics for OER intermediates than Ni sites and Ni-Fe dual-sites, while Mn sites with the polyvalent nature modulate the d-band center closer to Fermi level, facilitate the transfer of electrons across the catalyst surface, thus accelerating the reaction kinetics. This work is of considerable significance for achieving efficient and sustainable seawater electrolysis.

Developing an efficient photocatalyst is the key to realize the practical application of photocatalysis. The S-scheme heterojunction has great potential in photocatalysis due to its unique charge-carrier migration pathway, effective light absorption and high redox capacity. However, further enhancing the built-in electric field of the S-scheme, accelerating carrier separation, and achieving higher photocatalytic performance remain unresolved challenges. Herein, based on the continuously adjustable band structure of continuous solid-solution, a novel 0D/2D all solid-solution S-scheme heterojunction with adjustable internal electric field was designed and fabricated by employing a solid-solution of Zn_xCd_1-xS and Bi₂Mo_yW_1-yO₆ respectively as reduction and oxidation semiconductors. The synergistic optimization of effective light absorption, fast photogenerated carrier separation, and high redox potential leads can be tuned to promote photocatalytic activity. Under visible light, the S-scheme system constructed by Zn_0.4Cd_0.6S quantum dot (QDs) and Bi₂Mo_0.2W_0.8O₆ monolayer exhibits a high rate for photocatalytic degradation C₂H₄ (150.6 × 10^-3 min^-1), which is 16.5 times higher than that of pure Zn_0.4Cd_0.6S (9.1 × 10^-3 min^-1) and 53.8 times higher than pure Bi₂Mo_0.2W_0.8O₆ (2.8 × 10^-3 min^-1). Due to the unique charge-carrier migration pathway, photo-corrosion of Zn_xCd_1-xS is further inhibited simultaneously. In-situ irradiation X-ray photoelectron spectroscopy, photoluminescence spectroscopy, time-resolved photoluminescence, transient absorption spectroscopy and electron paramagnetic resonance provide compelling evidence for interfacial charge transfer via S-scheme pathways, while in-situ diffuse reflectance infrared Fourier transform spectroscopy identifies the reaction pathway for C₂H₄ degradation. This novel S-scheme photocatalysts demonstrates excellent performance and potential for the practical application of the fruits and vegetables preservation at room temperatures.

Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG) possesses excellent properties and stability than traditional poly(ethylene terephthalate) (PET). However, the production and application of PETG are restricted by the expensive monomer (1,4-cyclohexanedimethanol, CHDM). Direct upgrading of waste PET to dimethyl cyclohexane-1,4-dicarboxylate (DMCD) can promote the production of CHDM in large scale. In this work, a bifunctional Ru/UiO-66_def-SO₃H catalyst was synthesized and utilized in coupled methanolysis (of waste PET to dimethyl terephthalate (DMT)) and hydrogenation (of DMT to DMCD) under mild condition. Characterizations revealed that Ru/UiO-66_def-SO₃H possessed mesopores (dominant channels of 2.72 and 3.44 nm), enlarged surface area (998 m²·g^-1), enhanced acidity (580 μmol·g^-1), and Ru nanoparticles (NPs) dispersed highly (45.1%) compared to those of Ru/UiO-66. These combined advantages could accelerate the methanolysis and hydrogenation reactions simultaneously, promoting the performance of direct upgrading of PET to DMCD in one pot. In particular, the conversion of PET and yield of DMCD over Ru/UiO-66_def-SO₃H reached 100% and 97.7% at 170 °C and 3 MPa H₂ within 6 h. Moreover, Ru/UiO-66_def-SO₃H was also capable for the upcycling of waste PET-based products including beverage bottles, textile fiber and packaging film to DMCD.

Although the efficiency of poly(ethylene terephthalate) (PET) degradation has been successfully improved by depolymerase engineering, mostly by using Goodfellow-PET (gf-PET) as a substrate, efforts to degrade unpretreated PET materials with high crystallinity remain insufficient. Here, we endeavored to improve the degradation capability of a WCCG mutant of leaf-branch compost cutinase (LCC) on a unpretreated PET substrate (crystallinity > 40%) by employing iterative saturation mutagenesis. Using this method, we developed a high-throughput screening strategy appropriate for unpretreated substrates. Through extensive screening of residues around the substrate-binding groove, two variants, WCCG-sup1 and WCCG-sup2, showed good depolymerization capabilities with both high- (42%) and low-crystallinity (9%) substrates. The WCCG-sup1 variant completely depolymerized a commercial unpretreated PET product in 36 h at 72 °C. In addition to enzyme thermostability and catalytic efficiency, the adsorption of enzymes onto substrates plays an important role in PET degradation. This study provides valuable insights into the structure-function relationship of LCC.

Biocatalysis with nicotinamide adenine dinucleotide phosphate (NADP)-dependent oxidoreductases faces a challenge in improving the efficiency of the costly cofactor utilization. Although enzyme fusion can offer cofactor regeneration, the high-volume input and limited cofactor recyclability still make the enzymatic processes unsustainable. Therefore, it is of great significance to reduce cofactor input in a fusion enzyme (FuE) system, but no successful practice has been reported. Herein, we design a decapeptide bridge, RRRQRRRARR (R10), with high affinity for NADPH to construct fusion oxidoreductases (phenylacetone monooxygenase and phosphite dehydrogenase) for ester synthesis and NADP recycling. The peptide bridge enables electrostatic cofactor channeling that transports NADPH/NADP⁺ across the peptide between the enzymes’ NADP-binding pockets, so the fusion enzyme (FuE-R10) presents 2.1-folds and 2.0-folds higher conversions than mixed free enzymes and a flexible linker (GGGGSGGGGS)-fused enzyme, respectively, at NADPH/FuE of 0.1. The fusion enzyme, FuE-R5, bridged by a half-shortened linker, is proved more effective in facilitating cofactor channeling; compared to the mixed free enzymes, FuE-R5 exhibits two orders of magnitude reduction of NADPH input in ester synthesis. The work has thus demonstrated the potential of the cofactor bridging strategy in the development of sustainable cofactor-dependent cascade biocatalysis.