Large language models have recently brought a massive storm on modern society in all fields. While many view them as mere search engines for specific answers or text refinement tools like a chatbot, their broader applications remain largely unexplored. These large language models, consisting of billions of interconnected neurons, derived from all knowledge of the human, possess the remarkable ability to engage in smooth and precise conversations with individuals across the globe. Human-like intelligence enables them to address modern challenges and display immense potential in various scientific domains. In this perspective, we delve into the potential applications of modern large language model and its future iterations within the field of catalysis, aiming to shed light on how these AI-driven models can contribute to a deeper understanding of catalysis science and the intelligent design of catalysts.

Heterogeneous peroxymonosulfate (PMS)-based oxidation technology for water treatment requires innovative catalysts for efficient and selective production of desired reactive oxygen species (ROS), such as free radicals, singlet oxygen, catalyst-PMS* complexes, and high-valent metal-oxo species. Single-atom catalysts are featured with the maximized atom utilization as well as uniform and well-defined active sites, holding a great promise for effective and selective PMS activation. However, the structure-activity/selectivity relationships have not yet been well revealed owing to multiple ROS generation pathways and their complex interplay. Herein, we focus on the mechanisms of PMS activation by single-atom iron catalysts and identify the relationships of the geometric and electronic structures of single atom Fe centers to selective production of different reactive species/pathways. Moreover, in situ/operando techniques to monitor the dynamic evolution of active sites under practical working conditions and design of binuclear metal sites for synergistic catalysis will also be discussed.

Significant environmental issues have emerged from the increasing usage of fossil fuels, stimulating extensive interest in improving efficient energy production and storage systems. Electrocatalysis, which plays a crucial role in clean energy conversion, could foster the advancement of future sustainable technologies. Electrocatalytic activity is greatly enhanced by single-atom catalysts (SACs) because of their distinctive physical and chemical frameworks. The coordination environment can influence the geometry and electronic structure of SACs, contributing to the escalation of the efficiency of electrocatalytic for meeting practical needs. Due to their numerous micropores, greater surface area, and adjustable organic ligands, metal-organic frameworks (MOFs) have been shown to be an excellent approach to developing SACs. This review provides a complete summary of current instances involving the synthesis of SACs originating from MOFs. In addition, this review also addresses the impact of single-atoms (SAs) on electrocatalytic activity within the local coordination environment, including the spatial distribution, coordination structure, and local electronic structure. Besides, the density functional theory that provides theoretical support for the electrocatalytic reaction has summarized and analyzed the application of SACs in the electrocatalytic field.

Electrochemical conversion of CO₂ and H₂O to value-added products is an attractive approach for sustainable chemical production. Significant progress has been made in the past few decades in improving activity and selectivity, advancing this technology to practical application. Considering the next step for the electrochemical CO₂ reduction reaction, improving carbon utilisation efficiency, stability, and energy efficiency are essential. Bipolar membrane (BPM)-based electrolysers, which allow electrodes to be operated under different pH, are advantageous to tackle the challenge mentioned above. Herein, we introduced the current status of CO₂ electrolysers, followed by configuration, challenges, progress and outlook for combining reverse-bias BPM with different types of electrolysers. Our aim is to provide insight into developing carbon-efficient and energy-efficient CO₂RR systems towards practical application.

Extracting lipids from microalgal biomass presents significant potential as a cost-effective approach for clean energy generation. This can be achieved through the chemical conversion of lipids to produce fatty acid methyl esters via transesterification. The extraction mainly involves free fatty acids, phospholipids, and triglycerides, and requires less energy, making it an attractive option for satisfying the growing demand for fossil-derived energies. Several approaches have been explored for sustainable bioenergy production from microalgal species via catalytic, non-catalytic, and enzymatic transesterification. This review discusses recent insights into microalgal lipid extraction via solvent, Soxhlet, Bligh and Dyer’s, supercritical CO₂, and ionic liquids solvent methods and lipid conversion by transesterification and homo/heterogeneous acid/base catalyzed, enzymatic, non-catalytic, and mechanically/chemically catalyzed in-situ techniques towards algal bioenergy production. Technical advances in both extraction and conversion are necessary for the commercialization of renewable energy sources.

Amorphous ZIF-62(Co) glass (a_g-ZIF-62(Co)) was prepared and used as peroxymonosulfate (PMS) activator for the degradation of sulfamethoxazole (SMX). In the presence of 0.1 g/L a_g-ZIF-62(Co) and 0.2 mmol/L PMS, approximately 98.6% of SMX with an initial concentration of 5.0 mg/L was degraded within 30 min. The main reactive oxygen species (ROS) involved were sulfate radical (SO₄^•-) and singlet oxygen (¹O₂), with concentrations of 41.1 and 171.9 μmol/L, respectively. A fixed-bed reactor packed with a_g-ZIF-62(Co) was constructed for continuous SMX degradation, achieving nearly complete decontamination and 50% reduction in chemical oxygen demand over a period of 120 h. This study has paved a new avenue for exploring the potential application of metal-organic framework glasses in water purification through advanced oxidation processes.

The photocatalytic reduction of CO₂ to ethanol has attracted extensive attention, particularly for intricate C-C coupling. In this study, we propose a synthetic pathway for asymmetric CuNi heteronuclear diatoms (CuNi HDAs) by anchoring single Cu atoms on the Ni sites of (Ni, Zr)-UiO-66-NH₂ to enhance C-C coupling. Cu-(Ni,Zr)-UiO-66-NH₂ efficiently performs photocatalytic CO₂ conversion with a mass-specific activity (selectivity) of 3218 μmol·g_Cu^-1·h^-1 (97.3%). Spectroscopic analyses and density functional theory calculations revealed that CuNi HDAs with an asymmetric electronic distribution facilitated the activation of CO₂ molecules and lowered the C-C coupling barrier energy, thus promoting the formation of *OCCHO intermediates. This, in turn, led to a significant enhancement of ethanol selectivity. Furthermore, with interfacial Cu-Ni-O bonds as a rapid electron transport channel, CuNi HDAs enrich enough electrons for 12-electron CO₂ reduction, thereby enhancing ethanol productivity. This study provides a novel strategy for designing highly selective photocatalysts for CO₂ conversion at the atomic scale.

Single-atom catalysts (SACs) as a new class of peroxymonosulfate (PMS) activator are still limited by the low metal loading and activity. Here, we introduce a new strategy of interfacial coupling SACs with metal oxides to fine-tune the active single-atom sites and improve the atomic utilization efficiency. Taking Co₃O₄@Co₁/C₃N₅ as a case, the formation of heterostructures enhanced the activity of outer-sphere SACs for PMS activation, further upgrading the kinetics of diclofenac sodium degradation. The degradation rate of the composite increases by up to approximately 28.0 and 2.5 times compared to Co₃O₄and Co₁/C₃N₅, respectively. The Co₁-O (Co₃O₄) and Co-N (Co₁/C₃N₅) bonds between Co₁/C₃N₅ and Co₃O₄ make a tightly coupled interface for charge migration, which synergically optimizes the PMS adsorption configuration toward reactive species generation with lower activation energy. Co₃O₄@Co₁/C₃N₅ also exhibits excellent reusability and can be employed in broad application scenarios.

While biodegradable polymers such as polylactic acid (PLA) are widely used as alternatives to non-biodegradable polymers to address the plastic crisis, their biodegradation is difficult to control, and the process emits carbon. Conversion of PLA waste into value-added products via thermal and photocatalytic pathways is a promising solution. Herein, we describe a one-pot photothermal catalytic method that efficiently converts PLA into hydrogen and other valuable chemicals without requiring a concentrated KOH solution. Examining the catalytic properties of Pt/A-V-PCN (atomic-layered g-C₃N₄), Pt/TiO₂, and Pt/CdS for the photothermal reforming of lactic acid (LA) indicated superior hydrogen production for all the employed catalysts owing to the promotion effects of external heat on the excitation and utilization of carriers, as characterized by electrochemical impedance spectroscopy Nyquist and transient photocurrent (I-t) tests. We found that the cadmium sulfide (CdS) possesses excellent selectivity for converting LA into pyruvic acid (PyA). Using in situ electrochemical electron spin resonance spectroscopy experiments and density functional theory computations, we found that the high PyA selectivity for LA oxidation on the CdS surface was attributed to the different affinities of the active sites for C- and O-adsorbed species, resulting in enhanced dehydrogenation and hindered C-C cleavage. Furthermore, Pt/CdS demonstrated increased reactivity and achieved 98.1% selectivity for high-value pyruvic acid in liquid products during the one-pot photothermal upcycling of commercial PLA plastics. Hence, this study provides a strategy for developing more efficient catalytic routes for upcycling PLA and other polyesters.

The benzophenone structural unit is one of the most important functional groups in organic chemistry, which has a wide range of applications in drugs, light-curing agent, UV-light absorbent and so on. However, the traditional synthetic methods of benzophenone generally involve additives or toxic regents, leading to a large amount of waste and non-recyclable of [Pd] catalyst. Herein, we report Pd loaded carbon-modified TiO₂ (Pd/C-TiO₂) as an efficient and recyclable catalyst realized the generation of benzophenone through cross-coupling of benzaldehyde and iodobenzene under UV light irradiation, with the yield of 98% and selectivity up to 99%. Based on density functional theory (DFT) calculation and electron paramagnetic resonance (EPR) analysis, the reaction undergoes the Pd⁰-Pd^II-Pd^III catalytic pathway, that is, benzaldehyde directly activated to acyl radical under UV light and then attracted by Pd-iodobenzene complex to proceed the coupling reaction for benzophenone generation. Owing to the in-situ reduction of dissolved [Pd] through TiO₂ photocatalyst in the reaction system, good recyclability of metallic Pd can be achieved. This work not only shed light on a facile method for the synthesis of carbonyl-containing compounds but also offered a practical approach for minimizing the leaching of active metals in transition metal-catalyzed coupling reactions.

As a green and efficient technology, photocatalysis has practical application value, especially in terms of remediating environmental contamination issues. Biochar, the carbon material derived from sustainable calcined biomass waste, has attracted attention for its efficient adsorption capacity for pollutants. Herein, nitrogen(N)-doped biochar is prepared from sawdust biomass and dexterously coupled with Bi₂WO₆ to synthesize a range of Bi₂WO₆/N-doped biochar composites (BWO/Nx-BC), which are successfully utilized for photodegradation of chlorpyrifos (CPs). After introducing N atoms, BWO/N3-BC improves conductivity of electrons while maintaining strong adsorption properties, effectively preventing the charge recombination. BWO/N3-BC demonstrates high efficiency in ultrafast photodegradation of recalcitrant pesticides, destroying 99.0% of CPs in only 0.5 h. Besides, the degradation rate constants are 2.91 and 12.13 times higher than those of pure BWO and N3-BC, respectively. Given the complexity of real water environments, the effects of different operating parameters on photocatalytic activity are explored. Free radical scavenging assay and electron paramagnetic resonance are employed to uncover the key active species (•O₂^-, •OH, and h⁺), with •O₂^- being the predominant contributor, and the synergistic enhancement mechanism of adsorption-photodegradation of BWO/N3-BC is successfully revealed. Also, the intermediates of CPs are identified by HPLC-MS, and three possible degradation pathways are proposed. In addition, the ecotoxicity of CPs and their intermediates are evaluated by ecotoxicity test (E. coli culture) and Toxicity Evaluation Software Tool. This work may provide an opening for environmental remediation via photocatalysis integrated with waste biomass high-value valorization.

The utilization of semiconductor-based photocatalytic technology holds immense promise for harnessing solar energy. However, the inherent issue of strong Coulombic attraction between photo-generated electrons and holes within a single photocatalyst often leads to rapid recombination, limiting efficiency. Addressing this challenge, the development of S-scheme heterojunction photocatalysts has emerged as an effective strategy. Nevertheless, the impact of this spatial separation on the photocatalytic reaction has remained largely unexplored. This study reveals that the recombination of useless charge carriers significantly influences the oxidation product. In the pristine ZnIn₂S₄ system, the spatially unseparated holes interact with the H₂O₂ generated on the surface of ZnIn₂S₄, all of which are converted to •OH with higher oxidation ability, causing excessive oxidation of 5-hydroxymethylfurfural (HMF). Conversely, the BiOBr/ZnIn₂S₄ system, effective separation of electrons and holes in space, selectively oxidizes HMF into valuable 2,5-dimethylfuran (DFF) while efficiently generating H₂O₂ (1.15 mmol∙L^-1, 5 h). This outcome, elucidated through in-situ Fourier-transform infrared spectroscopy, density functional theory calculation, and femtosecond transient absorption spectroscopy, underscores the role of spatially separated charge carriers in influencing product selectivity within S-scheme heterojunctions. This work sheds new light on selective oxidation phenomena and underscores the significance of charge separation in S-scheme heterojunctions.

Metal-nitrogen-carbon single-atom catalysts (M-N-C SACs) have emerged as a highly promising material for ammonia synthesis from electrocatalytic nitrate reduction due to their isolated metal site and capacity to prevent the N-N coupling. However, understanding the structure-activity relationship at molecular level remains challenging because of the inhomogeneous MN_x structure presented in current synthesized M-N-C catalysts. In this study, we utilized metal phthalocyanine (MPc) as a model platform catalyst containing a uniform and well-defined MN₄ center to unravel their intrinsic activity tendency toward ammonia synthesis from nitrate reduction, both experimentally and theoretically. Our experimental results exhibit a significant activity difference for ammonia production in the order of FeN₄ > CuN₄ > NiN₄> MnN₄ > CoN₄ > ZnN₄, and among which the FeN₄ site delivers much higher faradic efficiency and the highest turnover frequency of 83.3% and 4395.2 h^-1 at -1.0 V vs. RHE, respectively. Density-functional theory calculations indicates that, compared to CoN₄ and MnN₄, the FeN₄ site not only has appropriate adsorption strength for NO_x intermediate species, but also has certain inhibitory effects on hydrogen evolution reaction process. These findings provide systematic and reliable guidance for catalyst synthesis toward nitrate reduction to NH₃ from both the experimental and computational perspectives.

Fabrication of porous hierarchical structures is an effective method to improve the photo-absorption capability of photocatalysts by enhancing the photogenerated charge separation and transfer. In-based metal-organic frameworks (MOFs) are utilized as self-sacrificial templates to synthesize various hierarchical In₂S₃ photocatalysts including hollow nanotubes/microtubes/ spheres and dodecahedrons by the sulfidation process. The porous hierarchical structures improve multiple refraction and reflection of the incident light, provide larger surface areas, and increase the light utilization and phase separation efficiency of the photogenerated carriers. As a result, the photocatalytic efficiency is much higher than that of the bulk and commercial In₂S₃. In particular, the hollow In₂S₃ nanotubes (HNTs) have the best photocatalytic properties boosting degradation rates of organic pollutants that are 135.6 and 446.9 times than those of the bulk and commercial-grade In₂S₃, respectively. Theoretical calculations, optical/electrical characterization, and free radical trapping experiments reveal that under the condition of light, the photogenerated electron hole pairs produced in In₂S₃-HNT can effectively separate due to its hierarchical porous structure. So, the In₂S₃-HNT can accumulate more reactive oxygen radicals. This novel self-sacrificial template method has large potential in the design and fabrication of hierarchical high-efficiency photocatalysts.

The rational design of Fe-N-C single-atom catalysts (SAC) requires a priori estimation of its activity with descriptors that require no additional calculations. In this study, we conducted a thorough investigation into the effect of the amount and the location of N and the position of edge atoms on intermediate adsorption energies, and then unveiled the critical topological factors. Our density functional theory calculations, energy decomposition analysis and bonding analysis on OH adsorption on finite graphitic Fe-N_x-C (x = 0-4) models discover that nitrogen not only concentrates electrons on the ligand onto donor atoms but also induces a more ionic nature in the Fe-ligand (Fe-L) bonds and partially disrupts the aromaticity of the ligand. The latter effect strongly correlates to the location of N. These effects influence the electrostatic, Pauli repulsive and orbital interactions that are involved in the Fe-O bond formation. Furthermore, our investigation also reveals that the size of SAC plays a role in binding only when the edge atom is situated in the ring containing donor atoms. Our work for the first time provides a comprehensive mechanism of OH adsorption on SAC and the influence of N and the size. It emphasizes the necessity of considering the quantity and the location of nitrogen, as well as the atoms surrounding the donor atoms when developing descriptors.

2D Substoichiometric covalent organic frameworks (2D-SSCOFs) are a new kind of porous organic polymers with accurate modifiability, good stability and abundant porosity. However, the strong exciton effects and slow charge transfer in 2D-SSCOFs can severely linker hinder the efficiency of photocatalytic energy conversion. Herein, we report a brand new thiophene-based 2D-SSCOF (PTT-COF) constructed by the Schiff base reaction using thiophene-enriched tri-topic linker and tetra-topic pyrene as structural unit precursors. Interestingly, PTT-COF exhibits a novel topology, high crystallinity, abundant delocalization electrons and weak excitonic effects. Inspired by the unique structural characteristics and photoelectrical performance, PTT-COF is utilized for photocatalytic hydrogen evolution. Experimental and theoretical studies have confirmed that introducing thiophene effectively modulates the topology of the COF, inducing local charge delocalization and redistribution, thus suppressing the excitonic effect and enhancing the photocatalytic performance. In addition, the periodic, uncondensed functional groups allow PTT-COF to be accurately modified by ferrocene carboxaldehyde as organic hole transporting ligands, leading to a further 40% enhancement in hydrogen evolution rate up to 79.610 mmol g^-1 h^-1. These findings in this work not only offer a brand new 2D-SSCOF with novel topology, but also provide new opportunities and directions for the ration design of 2D-SSCOF for emerging functional applications.

Photocatalysts featuring S-scheme heterojunctions offer considerable potential for both the photocatalytic CO₂ conversion and the degradation of antibiotics, providing practical solutions for energy crises and environmental challenges. In this work, 1D/2D CoTiO₃/g-C₃N₄ (CTO/CN) S-scheme heterojunction is synthesized through electrospinning and calcination. The close interweaving of g-C₃N₄ nanosheets around CoTiO₃ nanofibers creates ample contact areas and active sites, resulting in exceptional photocatalytic CO production capability. The optimal mass ratio of CoTiO₃ to g-C₃N₄ is 2%, and the CO and CH₄ yields are 46.5 and 0.825 μmol g^-1 h^-1. Moreover, comparing with monomeric g-C₃N₄, this composite achieves a better CO yield with 43.5 times and displays an impressive product selectivity of 98.3% for CO₂-CO photoreduction. In addition, the 2% CTO/CN photocatalyst demonstrates outstanding photocatalytic degradation efficiency, with degradation rates of 95.88%, 95.53%, and 71.23% for tetracycline hydrochloride, oxytetracycline, and ofloxacin, respectively. These enhanced photocatalytic properties are attributed to the S-scheme system constructed by CoTiO₃ with g-C₃N₄, maintaining strong oxidation-reduction capabilities while efficiently segregating photogenerated charges, with the existence of S-scheme heterojunction confirmed through various analyses. Furthermore, in situ studies and ¹³C calibration experiments reveal that CO and CH₄ originate from the photocatalytic CO₂ conversion, further highlighting the potential of this work in advancing CO₂ photoreduction. This study offers novel insights into designing effective S-scheme heterojunction photocatalysts for practical applications to address environmental and energy challenges.

The regioselective incorporation of deuterium to organic skeletons has gained ever-growing attention among scientific community. Herein, we present a robust and general protocol for site-specific deuteration through the cobalt catalyzed dehalogenative process. Using D₂O as the economical deuterium reagent, we achieved excellent substrate compatibility across a wide collection of organohalides or pseudo-halides, such as aryl, alkenyl, benzyl, allyl, or alkyl halides and propargyl acetates. Preliminary experimental evidences and related DFT calculation are also presented to support a mechanistic scenario involving a Co(I)-C(III)-Co(I) cycle. The generality and potential utilization of this moisture-insensitive catalysis have also been demonstrated by the selective deuterodehalogenation of drug-like candidates, concise synthesis of D-labeled pharmaceutical molecule, as well as the stepwise hydrogen isotope exchange of bioactive compounds.

Controlling the morphology of Pt nanostructures can provide a great opportunity to improve their catalytic properties by increasing their active sites and atomic utilization. Here, Pt nanodentrites (NDs) dispersed on intrinsic vacancy-rich hollow nitrogen-doped carbon (Pt@HNC-V) have been successfully prepared through an integrated strategy of in situ Cl^- mediated growth and carbon intrinsic vacancy engineering. Raman and electron paramagnetic resonance measurements have demonstrated that our method enables selective transformation of precursors into vacancy-rich samples or vacancy-free ones through a variable etching route. Moreover, X-ray absorption and X-ray photoelectron spectroscopy further verified that the vacancy-rich sample (Pt@HNC-V-800) demonstrates a lower Pt-Pt bond coordination number (8.64) and a stronger electron-donating effect of Pt compared with the vacancy-free Pt@HNC sample. In addition, density functional theory calculations indicate that the vacancy-rich Pt@HNC-V lowers the oxygen overpotential, resulting in optimized adsorption energies of oxygen reduction reaction (ORR) intermediates on Pt NDs and thus yielding improved oxygen reduction reaction activity. Benefiting from Pt NDs with abundant active sites and the strong electronic effect between them and the intrinsic carbon vacancy substrate, the half-wave potential of ORR for Pt@HNC-V-800 is as high as 0.947 V, and the mass activity is 1.55 A mg^-1Pt, which is significantly higher than that of commercial Pt/C. The synergy between Pt NDs and carbon intrinsic vacancy engineering can enhance the overall ORR performance, which is beneficial for material preparations in the field of energy and catalysis.

Synthesizing low-cost electrocatalysts with rich metal-nitrogen-carbon active sites for the oxygen reduction reaction (ORR) is critical for developing high-performance Zn-air batteries. However, it is challenging for the pyrolysis cheap molecular precursors (such as melamine and iron salts) is challenging because of the spontaneous aggregation of metal components and undesired byproducts during pyrolysis. Herein, we describe an approach to generate graphene-supported accessible Fe-N-C active sites by introducing a removable bismuth compound that efficiently inhibits the formation of iron-related particles and tubular carbon structures. The graphene-supported Fe(Bi)-N-C electrocatalyst exhibited high ORR activity under both alkaline (E_1/2 ~0.916 V) and acidic (E_1/2 ~0.784 V) conditions, along with excellent durability (15 mV degradation after 10 k cycles accelerated test). Using the catalytic material as the cathode, the Zn-air battery delivered a high power density of 201.4 mW cm^-2 and a high stability over 1000 cycles. This investigation presents a promising controlled pyrolysis solution for the scalable synthesis of low-cost, high-performance metal-nitrogen-carbon-based catalytic materials.

Heterogeneous single-metal-site catalysts frequently encounter issues related to the poor stability of their coordination structures, hindering their industrial applications. Synthesizing bimetallic single-metal-site catalysts with two closely connected single sites may realize the full potential of single-site catalysts. Herein, we present a “top-down” dispersion process to prepare bimetallic single-metal-site catalysts from Pd-Ag alloy nanoparticles induced by CO and CH₃I mixture, with the unique binuclear complex structure of Pd₁-Ag₁ established as PdI₂(CO)-I₂-AgI by combined characterization. The Pd₁-Ag₁/activated carbon (AC) catalyst showed a three times increase in conversion for acetylene dialkoxycarbonylation compared to Pd₁/AC, owing to the promotive effect of the single-Ag-site via the binuclear complex configuration. Moreover, Pd₁-Ag₁/AC showed 98% selectivity for 1,4-unsaturated dicarboxylic acid esters over ten cycles without apparent decay, with the activated adsorption amount of acetylene doubled and the reduction of active Pd₁^δ+ species partially inhibited. According to density functional theory calculations, the Pd₁-Ag₁/AC catalyst exhibited a substantially lower reaction energy barrier of 0.45 eV for the rate-determining step compared with that of the Pd₁/AC catalyst (1.06 eV). This study provides insight into the preparation and synergetic catalysis of bimetallic single-metal-site catalysts.

Electrocatalytic nitrate reduction reaction (NO₃RR) has been capturing immense interest in the industrial application of ammonia synthesis, and it involves complex reaction routes accompanied by multi-electron transfer, thus causing a challenge to achieve high efficiency for catalysts. Herein, we customized the Cu-O-Ti-O_v (oxygen vacancy) structure on the Cu/TiO₂ catalyst, identified through density functional theory (DFT) calculations as the synergic active site for NO₃RR. It is found that Cu-O-Ti-O_v site facilitates the adsorption/association of NO_x^- and promotes the hydrogenation of NO₃^- to NH₃ via adsorbed ^*H species. This effectively suppresses the competing hydrogen evolution reaction (HER) and exhibits a lower reaction energy barrier for NO₃RR, with the reaction pathways: NO₃^* → NO₂^* → HONO^* → NO^* → ^*NOH → ^*N → ^*NH → ^*NH₂ → ^*NH₃ → NH₃. The optimized Cu/TiO₂ catalyst with rich Cu-O-Ti-O_v sites achieves an NH₃ yield rate of 3046.5 μg h^-1 mg_cat^-1 at -1.0 V vs. RHE, outperforming most of the reported activities. Furthermore, the construction of Cu-O-Ti-O_v sites significantly mitigates the leaching of Cu species, enhancing the stability of the Cu/TiO₂ catalyst. Additionally, a mechanistic study, using in situ characterizations and various comparative experiments, further confirms the strong synergy between Cu, Ti, and O_v sites, which is consistent with previous DFT calculations. This study provides a new strategy for designing efficient and stable electrocatalysts in the field of ammonia synthesis.

A series of proto-type photocatalytic air purifier (AP (N_x-C_y)) systems are built with a nitrogen-doped TiO₂ (N-TiO₂)-impregnated honeycomb (HC) filter for photocatalytic decomposition of 0.5-5 ppm formaldehyde (FA: CH₂O) vapor under varying conditions and UV-LED light (1 watt). The binary codes of N_x and C_y in AP systems are used as the composition identifiers to represent N/Ti molar ratios (0 to 20) and N-TiO₂ concentration (2 to 20 mg mL^-1), respectively. The AP (N₁₀-C₁₀) is found as an optimum unit with the highest capability to boost the catalytic conversion of CH₂O to CO₂ (yield = 89.2% over 10^th cycles and the clean air delivery rate (CADR) of 9.45 L min^-1 in dry air). The superior charge carrier lifetime (τ_a: 1.70 ns) of N₁₀-C₁₀ over others (e.g., 1.37 ns for pure TiO₂) should indicate the influential role of N-defects (N_o) in reducing the bandgap (3.10 eV) and in creating defect-related oxygen vacancy (OVs-Ti³⁺) states as predicted by the density functional theory (DFT) simulation. The photocatalytic oxidation pathway of CH₂O, when assessed by diverse approaches (e.g., in-situ diffuse reflectance infrared Fourier transform, electron paramagnetic resonance, and DFT analyses), is found to involve several energetically favorable intermediate steps (such as exothermic covalent adsorption of CH₂O to bridged O/OH groups on TiO₂-OV {110} surface in the form of CH₂O₂ followed by catalytic dehydrogenation/oxidation reactions to yield CO₂ through direct route: CH₂O₂/HCOO^- + •OH → H₂O + CO₂). These steps are supported by the calculated density of states (DOS) for chemically active Ti-atom on {101} surface with N-impurity. The presence of N_o-defects and OVs is expected to influence the reaction energetics and intermediates for efficient mineralization in humidified conditions by lowering the activation barriers. This study offers valuable insights into the design and construction of an advanced photocatalytic system for efficient mineralization of aldehyde VOCs in ambient air.

Metal single-atom/atomic cluster catalysts (SA/AC) have emerged as effective electrocatalysts for the CO₂ reduction reaction (CO₂RR) due to their high metal atom utilization and controllable metal coordination environments. However, the designing and tuning of the local electronic environments of SA/AC ensembles remain a significant challenge. In this work, we develop a single-atom-modified atomic cluster copper catalyst (Cu SA/ACs) for CO₂RR. The SA/AC-induced modulation of the local electronic structure enhances CO₂ adsorption on the atomic cluster; additionally, the atomic cluster provides abundant active hydrogen for CO₂ protonation by mediating hydrolysis dissociation on the SAs. Consequently, compared to copper single-atom catalysts (Cu SACs), the Cu SA/ACs exhibit significantly improved activity, the current is 3.6 times that of Cu SACs, and the Faradaic efficiency of CO rose from 27.15% to 98.94%. The Cu SA/ACs catalyst can efficiently reduce CO₂ to CO in flow-cell configuration, and the CO selectivity is 93.06% at a current density of 600 mA cm^-2. The maximum energy efficiency of the cathode is 61.9%, which is superior to that of most CO₂-to-CO catalysts. This work provides a new perspective for developing efficient SA/AC catalysts.

Photocatalytic water splitting to produce H₂ using semiconductor photocatalysts is a reliable approach to alleviating energy shortages and environmental pollution. However, the inadequate light-harvesting ability, rapid photogenerated carrier recombination, and inferior redox capacity of the individual photocatalysts restrict their photocatalytic activity. To address these limitations, a hierarchical S-scheme heterojunction of ZnIn₂S₄-nanosheet-decorated flower-like TiO₂ microspheres for enhancing photocatalytic H₂ evolution, purposely constructed through in situ chemical bath deposition, has been reported. The as-synthesized TiO₂/ZnIn₂S₄ heterojunctions exhibited ZnIn₂S₄-content-dependent photocatalytic activity for solar-driven H₂ evolution. As a result, the optimized TiO₂/ZnIn₂S₄ heterojunction exhibited a superior photocatalytic H₂ evolution rate of 6.85 mmol g^-1 h^-1, approximately 171.2- and 3.9-fold with respect to that obtained on pure TiO₂ and ZnIn₂S₄, respectively, mainly attributed to the unique hierarchical structure, extended light-harvesting ability, enhanced redox capacity, and improved separation and transfer efficiencies of the photogenerated carriers induced by the S-scheme heterojunctions. Simultaneously, a detailed analysis of the S-scheme electron transfer pathway in the TiO₂/ZnIn₂S₄ heterojunction was performed using in situ irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy. This study provides insights into the design of highly active heterojunction photocatalysts for sustainable solar-to-fuel energy conversion.

Hydrogen peroxide (H₂O₂) is a high-value-added chemical for multitudinous industrial applications. Being compared with traditional anthraquinone processes, it is an eco-friendly and promising strategy to accomplish catalytic reduction of molecular oxygen for H₂O₂ production with the aid of mechanical and solar energy. It was the first attempt to combine a porphyrin-based metal-organic framework (PCN-224) and piezoelectric semiconductor (g-C₃N₄) to fabricate heterostructures (abbreviated as CP-x) with core-shell structure for piezo-photocatalytic H₂O₂ production. The introduction of PCN-224 not only widened light absorption range and accelerated electron transfer, but also facilitated the hydrogenation and generation of OOH^*, which was more prone to direct two-electron O₂ reduction. Furthermore, benefitting from the synergism of the piezo-photocatalysis, an exceptional piezo-photocatalytic H₂O₂ evolution rate of 5.97 mmol g^-1 h^-1 with solar-to-chemical conversion (SCC) efficiency of 0.14% was achieved by the optimum CP-5 heterojunction. This achievement significantly surpassed the previously reported g-C₃N₄-based and MOF-based materials. The use of rainwater as proton sources also allowed an impressive H₂O₂ generation rate (2.78 mmol g^-1 h^-1), thereby this outcome was of great significance to the rainwater utilization. This work contributed an in-depth understanding of piezo-photocatalytic O₂ reduction and provided an alternative way for the development of porphyrinic MOFs heterojunctions for synthesis of H₂O₂.