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Chinese Journal of Catalysis
2019, Vol. 40, No. 11
Online: 18 November 2019

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Cover: The year 2019 marks the 70th anniversary of the Dalian Institute of Chemical Physics,Chinese Academy of Sciences (abbreviated as DICP).Since its foundation,DICP has been at the forefront of fundamental and applied sciences and technologies that closely response the scientific and economic demands of China.After the efforts of several generations,DICP has gained a high reputation in chemistry research,covering from fundamental studies,technology development to industrial applications.Especially,DICP has made great contributions in the field of catalysis.To celebrate the 70th anniversary,the journal publishes this special issue.Internationally renowned catalysis scientists were kindly invited to make contributions.The speical issue contains 23 papers,including 2 Editorials,3 Reviews,1 Communication,and 17 research Articles that cover aspects of both fundamental studies and industrial applications.

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Table of Contents for VOL.40 No.11 2019, 40 (11):  0-0.  Abstract ( 24 )   PDF (4001KB) ( 149 )

Editorials

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Preface to Special Issue on Celebrating the 70th Anniversary of Dalian Institute of Chemical Physics, Chinese Academy of Sciences Can Li, Tao Zhang, Zhongmin Liu 2019, 40 (11):  1589-1590.  DOI: 10.1016/S1872-2067(19)63457-1 Abstract ( 58 )   [Full Text(HTML)] () PDF (691KB) ( 275 )

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History of the Dalian Institute of Chemical Physics and the Friendship between China and Japan in catalysis S. Ted Oyama, Qin Xin, Guoxing Xiong, Wenjie Shen, Jie Xu, Hongmei Yin, Youzhu Yuan, Haichao Liu, Huidong Zheng 2019, 40 (11):  1591-1614.  DOI: 10.1016/S1872-2067(19)63483-2 Abstract ( 59 )   [Full Text(HTML)] () PDF (3520KB) ( 344 )   This article presents a history of the origins of the Dalian Institute of Chemical Physics, Chinese Academy of Sciences (Abbreviated as DICP) and relates the recent friendship between China and Japan in the field of catalysis. Although the official beginning of DICP is in 1949 with the birth of the People's Republic of China, there are earlier roots that went back to the defeat of Russia by Imperial Japan in 1905. This began a period of occupation and exploitation of Northest Asia by Japan which did not end until its defeat by Allied forces in 1945. During the period of occupation, a laboratory was created called the Central Research Laboratory of the South Manchurian Railroad Company, which was staffed by the best and brightest researchers from Japan, and was able to develop new processes in chemicals and synthetic fuels that fed the Japanese Imperial forces. Between 1945 and 1949, Dalian was administered by the Soviet Union, and the removable equipment from the Laboratory was taken. In this period one individual stood out, the Laboratory Director Marusawa Tsuneya, who risked his life to preserve the scientific records and staff of the institute, and then stayed in Dalian for ten years after the Second World War to help China rebuild its capabilities. The Central Research Laboratory is still preserved as the Old Campus of DICP. The origin of the friendship between China and Japan in catalysis can be traced to Professor Morikawa Kiyoshi, who worked in the Central Research Laboratory and helped commercialize a shale coal liquefaction process. Upon his return to Japan he became Professor at the Tokyo Institute of Technology and in 1975 organized the first visit by Japanese academics to China. This was reciprocated in visits to Japan in 1977 and 1980 by top researchers such as Zhang Dayu, Min Enze, Tsai Khirui, Lu Jiaxi, and Lin Liwu. This resulted in numerous contacts between individuals, which multiplied geometrically. Notably among these were the personal interactions between Guo Xiexian, the Vice-Director of DICP and Tamaru Kenzi, a Professor at the University of Tokyo, which led to a friendship lasting decades and encompassing generations. In 1981, Guo Xiexian organized the first China-Japan-USA Symposium in Dalian, assisted by Tamaru Kenzi, which was attended by over 90 scientists. This meeting was a big success, and was to lead to the organization of many other multi-country conferences, further promoting exchanges. It culminated with the hosting of China of the 16th International Congress on Catalysis in 2016 in Beijing, with Li Can as President. Today DICP is a sprawling organization with over 1300 permanent staff, and is one of the powerhouses of catalysis in the world. From 2000, it has been led by Directors Bao Xinhe, Zhang Tao, and Liu Zhongmin. The Institute is making enormous contributions to research and producing cut-ting-edge technology, and its future is bright.

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An odyssey: the way Chinese catalysis towards the world Qin Xin, Yongxue Li 2019, 40 (11):  1615-1626.  DOI: 10.1016/S1872-2067(19)63482-0 Abstract ( 57 )   [Full Text(HTML)] () PDF (3048KB) ( 270 )   The 16th International Catalysis Congress (16th ICC) was successfully held in China in July 2016. This paper reviewed the development of catalytic science and technology of China from scratch to small then to large under the efforts of several generations. In 1950s, catalysis discipline was first set up to train early catalytic professionals in Jilin University, Peking University and Xiamen University. Subsequently, a large research team was formed in colleges and universities, the Academy of Sciences, the Enterprise Research Institute to carry out a large number of catalytic researches. Along with the Chinese reform and opening-up, the spring of science came, and the state started to emphasize and strongly support scientific research. Chinese catalytic researchers began to enter the international catalytic academic exchange platform. Famous foreign scientists are invited to visit China and a large number of visiting scholars and foreign students have been sent to the United States, Europe and Japan, many of them have become well-known professors, and grown into catalytic academic elites. The first China-Japan-USA Symposium on Catalysis was held in Dalian in 1982, and it was expanded to become the Asian-Pacific Congress on Catalysis (APCAT), one of the three regional catalytic conferences in the world. After several generations of bidding for the organization of the International Catalytic Congress three times, China won the right to host the 16th ICC. It has effectively promoted the Chinese catalytic academic circles to the international academic ones and improved the influence of catalysis communities in China significantly. The great development in catalytic research and technology has condensed the efforts of several generations of catalysts. To make China a catalytically strong country, there is still a long way to go. We hope that the contemporary scientists can accomplish this historical task.

Reviews

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Importance, features and uses of metal oxide catalysts in heterogeneous catalysis Jacques C. Védrine 2019, 40 (11):  1627-1636.  DOI: 10.1016/S1872-2067(18)63162-6 Abstract ( 285 )   [Full Text(HTML)] () PDF (1203KB) ( 758 )   This short review paper aims at assembling the present state of the art of the multiuses of metal oxides in heterogeneous catalysis, concerning liquid and gaseous phases of the reactant mixtures on solid catalysts. It includes the description of the main types of metal oxide catalysts, of their various preparation procedures and of the main reactions catalysed by them (acid-base type, selective and total oxidations, bi-functional catalysis, photocatalysis, biomass treatments, environmental catalysis and some of the numerous industrial applications). Challenges and prospectives are also discussed.

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Advanced characterization for industrial catalysis applications Shelly Kelly, Wharton Sinkler, Lijun Xu, Sergio Sanchez, Cem Akatay, Haiyan Wang, John Qianjun Chen 2019, 40 (11):  1637-1654.  DOI: 10.1016/S1872-2067(19)63372-3 Abstract ( 85 )   [Full Text(HTML)] () PDF (1878KB) ( 309 )   The interplay between analytical technique and industrial practice has been central in the development of catalytic materials for processing petroleum. This article presents reviews of key aspects of two of the most important classes of catalytic materials:noble-metal Pt nanoparticles (NPs) on alumina, which are the basis of catalytic reforming; and layered sulfides of Mo and W, which catalyze hydrogenation and hetero-atom removal in hydroprocessing. The state of understanding of Pt cluster growth and resulting structures, as developed using X-ray absorption spectroscopy and STEM, is reviewed. Influences of both Pt reduction temperature in hydrogen gas, and oxidizing pretreatment conditions prior to Pt reduction, are considered. Recent work by the present authors on Pt NP structure evolution is presented in the context of the previous work. A review is subsequently presented of layered sulfide based NPs, summarizing contributions from a range of analytical techniques. Work on active site structures of sulfide NPs is reviewed, focusing particularly on the critical interactions of active edge sites with sulfur and hydrogen in chemisorption, physisorption, and spillover interactions. New temperature programmed reduction (TPR) results are presented for supported and unsupported sulfide NPs. Structural changes in TPR of alumina-supported MoS2 are investigated using extended X-ray absorption fine structure and density functional theory modeling, and are determined to arise from removal of identifiable edge-site sulfur species.

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A modeling analysis of molecular orientation at interfaces by polarization-dependent sum frequency generation vibrational spectroscopy Xia Li, Günther Rupprechter 2019, 40 (11):  1655-1667.  DOI: 10.1016/S1872-2067(19)63357-7 Abstract ( 93 )   [Full Text(HTML)] () PDF (1358KB) ( 383 )   Sum frequency generation (SFG) vibrational spectroscopy has been proven an excellent tool to measure the molecular structures, symmetries and orientations at surfaces/interfaces because of its strong polarization dependence. However, a precise quantitative analysis of SFG spectral intensity and molecular orientation at interfaces must be carefully performed. In this work, we summarized the parameters and factors that are often ignored and illustrated them by evaluating studies of CO adsorption on the (111) facet of platinum (Pt) and palladium (Pd) single crystals at the gas (ultra-high vacuum, UHV)/solid interfaces and methanol (water) adsorption at the air/liquid (solid/liquid) interfaces in the presence of sodium iodide (chloride) salts. To intuitively estimate the influence of incidence angles and refractive indices on the SFG intensity, solely a defined factor of|Fyyz|was discussed, which can be individually separated from the macroscopic second-order non-linear susceptibility χyyz(2) term and represents the SSP intensity. Moreover, effects of refractive indices and the molecular hyperpolarizability ratio (R) were discussed in the orientational analysis of interfacial CO and methanol molecules. When IPPP/ISSP was identical, molecules with a larger R had smaller tilting angles (θ) on Pt (assuming θ<51°), and CO molecules on Pd would tilt much closer to the surface than they did on Pt. A total internal reflection (TIR) geometry enhanced the SFG intensity, but it also amplified the influence of refractive index on SFG intensity at the solid (silica)/liquid interface. The refractive index and R-value had similar influence on the methanol orientation in the presence of sodium iodide salts at air/liquid and solid/liquid interfaces. This work should provide a guideline for analyzing the orientation of molecules with different R, which are adsorbed on catalysts or located at liquid interfaces involving changes of refractive indices.

Communication

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Metal selenides for photocatalytic Z-scheme pure water splitting mediated by reduced graphene oxide Shanshan Chen, Takashi Hisatomi, Guijun Ma, Zheng Wang, Zhenhua Pan, Tsuyoshi Takata, Kazunari Domen 2019, 40 (11):  1668-1672.  DOI: 10.1016/S1872-2067(19)63326-7 Abstract ( 125 )   [Full Text(HTML)] () PDF (1138KB) ( 410 )   Supporting Information Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H2 production. In the work, solid solutions of zinc selenide and copper gallium selenide with absorption edge wavelengths ranging from 480 to 730 nm were developed. Using these metal selenides as H2-evolving photocatalysts, CoOx/BiVO4 as the O2-evolving photocatalyst, and reduced graphene oxide as the electron mediator, all-solid-state Z-scheme overall pure water splitting systems were constructed. The rate of photocatalytic H2 evolution from aqueous solutions containing Na2S and Na2SO3 as the electron donors was evaluated while employing these selenide photocatalysts at various Zn/(Zn+Cu) and Ga/Cu molar ratios. The data demonstrate that efficient Z-scheme overall water splitting was significantly correlated to the photoelectrochemical performance of the selenide photocatalysts acting as photocathodes, rather than the photocatalytic activities of these materials during the sacrificial H2 evolution.

Articles

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Prospect of vapor phase catalytic H2O2 production by oxidation of water Mayfair C. Kung, Harold H. Kung 2019, 40 (11):  1673-1678.  DOI: 10.1016/S1872-2067(19)63327-9 Abstract ( 61 )   [Full Text(HTML)] () PDF (633KB) ( 290 )   Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.

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Zinc single atoms on N-doped carbon: An efficient and stable catalyst for CO2 fixation and conversion Xinjiang Cui, Xingchao Dai, Annette-Enrica Surkus, Kathrin Junge, Carsten Kreyenschulte, Giovanni Agostini, Nils Rockstroh, Matthias Beller 2019, 40 (11):  1679-1685.  DOI: 10.1016/S1872-2067(19)63316-4 Abstract ( 81 )   [Full Text(HTML)] () PDF (1463KB) ( 532 )   Supporting Information The cycloaddition of epoxides and carbon dioxide represents a straightforward and atom-efficient method for synthesis of cyclic carbonates and utilization of CO2. So far, homogeneous metal complexes have been mainly applied for such transformations. Here, we describe the synthesis of novel heterogeneous Zn-based catalysts, which were conveniently prepared by pyrolysis of an active-carbon-supported phenanthroline-ligated Zn(OAc)2 complex. Detail structural characterizations proved the existence of single zinc sites in the active material. Compared to a Zn-based nanoparticle (Zn-NP) catalyst, the resulting single metal atom catalyst (SAC) displayed improved activity and stability for the cycloaddition of epoxides. By applying the optimal catalyst, a variety of carbonates were successfully obtained in high yields with good functional group tolerance.

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Methanol oxidation over shell-core MOx/Fe2O3 (M=Mo, V, Nb) catalysts Pip Hellier, Peter P. Wells, Michael Bowker 2019, 40 (11):  1686-1692.  DOI: 10.1016/S1872-2067(19)63350-4 Abstract ( 93 )   [Full Text(HTML)] () PDF (710KB) ( 399 )   Supporting Information We present a comparison of Mo, V and Nb oxides as shell materials atop haematite cores used for selective methanol oxidation. While Mo and V both yield high selectivity to formaldehyde, Nb does not. Very different reactivity patterns are seen for Nb, which mainly shows dehydrogenation (to CO) and dehydration (to DME), indicating the lack of a complete shell, while Raman spectroscopy shows that the Mo and V formation process is not followed by NbOx. We suggest this is due to the large differences in mobility within the solid materials during formation, NbOx requiring significantly higher (and deleterious) calcination temperatures to allow sufficient mobility for shell completion.

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Effect of the catalyst preparation method on the performance of Ni-supported catalysts for the synthesis of saturated amines from nitrile hydrogenation D. J. Segobia, A. F. Trasarti, C. R. Apesteguía 2019, 40 (11):  1693-1703.  DOI: 10.1016/S1872-2067(18)63179-1 Abstract ( 48 )   [Full Text(HTML)] () PDF (1245KB) ( 307 )   The liquid-phase hydrogenation of butyronitrile to saturated amines was studied on sili-ca-supported Ni catalysts prepared by either incipient-wetness impregnation (Ni/SiO2-I) or ammonia (Ni/SiO2-A) methods. A Ni/SiO2-Al2O3-I sample was also used. Ni/SiO2-I was a non-acidic catalyst containing large Ni0 particles of low interaction with the support, while Ni/SiO2-A was an acidic catalyst due to the presence of Ni2+ species in Ni phyllosilicates of low reducibility. Ni/SiO2-I formed essentially butylamine (80%), and dibutylamine as the only byproduct. In contrast, Ni/SiO2-A yielded a mixture of dibutylamine (49%) and tributylamine (45%), being the formation of butylamine almost completely suppressed. The selective formation of secondary and tertiary amines on Ni/SiO2-A was explained by considering that butylamine is not release to the liquid phase during the reaction because it is strongly adsorbed on surface acid sites contiguous to Ni0 atoms, thereby favoring the butylimine/butylamine condensation to higher amines between adsorbed species.

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Catalytic dehydrogenation of formic acid over palladium nanoparticles immobilized on fibrous mesoporous silica KCC-1 Siqian Zhang, Yingjie Qian, Wha-Seung Ahn 2019, 40 (11):  1704-1712.  DOI: 10.1016/S1872-2067(19)63303-6 Abstract ( 67 )   [Full Text(HTML)] () PDF (808KB) ( 293 )   Supporting Information Uniform Pd nanoparticles immobilized on N-(3-trimethoxysilylpropyl)diethylenetriamine (PDETA)-functionalized fibrous silica KCC-1 (Pd/KCC-1-PDETA) were prepared with a mean Pd particle size of 2.8 nm. After characterization using powder X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption-desorption isotherms, Pd/KCC-1-PDETA was used as catalyst for additive-free dehydrogenation of formic acid to produce H2. Pd nanoparticle catalysts supported on two other mesoporous silica materials (MSF and KIT-6) were also synthesized to examine how the support affects the reaction. Among the three catalysts, Pd/KCC-1-PDETA exhibited significant catalytic activity (a turnover frequency of 332 h-1 at 323 K and 100% selectivity towards hydrogen), owing to the unique fibrous morphology of KCC-1 and the presence of amine groups that reduced the Pd particle size and improved the access of reactant to the catalytically active Pd sites. The influence of Pd loading (2-10 wt.%), reaction temperature, and reaction time was also examined for the dehydrogenation reaction. Pd/KCC-1-PDETA was recovered easily after the reaction and showed good reusability up to five times without any significant loss in catalytic performance.

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Prins cyclisation of (-)-isopulegol with benzaldehyde over ZSM-5 based micro-mesoporous catalysts for production of pharmaceuticals Ekaterina Kholkina, Paivi Maki-Arvela, Chloe Lozachmeuer, Roman Barakov, Nataliya Shcherban, Dmitry Yu. Murzin 2019, 40 (11):  1713-1720.  DOI: 10.1016/S1872-2067(19)63305-X Abstract ( 134 )   [Full Text(HTML)] () PDF (854KB) ( 333 )   Several ZSM-5 derived micro-mesoporous catalysts were investigated in Prins cyclisation of (-)-isopulegol with benzaldehyde acting as a reactant and a solvent for production of heterocyclic oxygen containing 2H-chromene derivatives including the tetrahydropyran structure and exhibiting biological activity. The investigated catalysts were characterized by nitrogen adsorption, ammonia temperature programmed desorption, adsorption-desorption of pyridine and 2,6-di-tert-butylpyridine with Fourier transform infrared spectroscopic control. For the Prins reaction performed at 70℃, the highest yield of the desired product, equal to 67% at complete conversion of (-)-isopulegol, was obtained over a micro-mesoporous catalyst containing an optimum amount of strong acid sites and mesopores, being 12 fold larger than the size of the desired product.

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Hydrodeoxygenation of anisole over different Rh surfaces Nhung N. Duong, Darius Aruho, Bin Wang, Daniel E. Resasco 2019, 40 (11):  1721-1730.  DOI: 10.1016/S1872-2067(19)63345-0 Abstract ( 316 )   [Full Text(HTML)] () PDF (1709KB) ( 522 )   Supporting Information The cleavage of the alkoxy (Ar-O-R) ether bond present in anisole is an interesting hydrodeoxygenation (HDO) reaction, since this asymmetric group contains two different C-O bonds, Caryl-O or Calkyl-O, which could potentially cleave. Recent work on the HDO of anisole over Pt, Ru, and Fe catalysts has shown that a common phenoxy surface intermediate is formed on all three metals. The subsequent reaction path of this intermediate varies from metal to metal, depending on the metal oxophilicity. Over the less oxophilic Pt, phenol is the only primary product. By contrast, on the more oxophilic Fe catalyst, the sole primary product is benzene instead of phenol. On Ru, with intermediate oxophilicity, both benzene and phenol are primary products. In this contribution, we have investigated Rh catalysts of varying surface nanostructures. A combination of experimental measurements and computational calculations was used to explore the effects of varying metal coordination number, an additional parameter that can be used to control the oxophilicity of a metal. The results confirm that metal oxophilicity is a good descriptor for HDO performance of metal catalysts and it can be controlled via selection of metal type and/or metal extent of coordination. Small Rh metal clusters with low coordination metal sites are more active for the deoxygenation pathway but also quickly deactivated while large clusters with high coordination sites are more active toward hydrogenation and more stable.

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On the role of cobalt carbidization in higher alcohol synthesis over hydrotalcite-based Co-Cu catalysts Janine Nebel, Stefan Schmidt, Qiushi Pan, Katrin Lotz, Stefan Kaluza, Martin Muhler 2019, 40 (11):  1731-1740.  DOI: 10.1016/S1872-2067(19)63344-9 Abstract ( 106 )   [Full Text(HTML)] () PDF (1004KB) ( 438 )   Supporting Information Co-Cu-based catalysts are widely applied in higher alcohol synthesis (HAS) from synthesis gas. Although the nature of the active sites is still not fully understood, the formation of Co2C under HAS conditions seems to play a major role. A CO pretreatment procedure was developed allowing a systematic investigation of the influence of cobalt carbidization on the structural properties and catalytic performance of the catalysts. By exposing the catalyst to a CO-containing atmosphere prior to HAS, Co enrichment of the catalyst surface occurred followed by carbide formation. This surface modification decreased the formation of hydrocarbons and enhanced the formation of C2+OH. The catalyst pretreated with CO at 20 bar achieved the highest selectivity to ethanol and the lowest hydrocarbon selectivity.

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Zr(IV) surface sites determine CH3OH formation rate on Cu/ZrO2/SiO2-CO2 hydrogenation catalysts Erwin Lam, Kim Larmier, Shohei Tada, Patrick Wolf, Olga V. Safonova, Christophe Copéret 2019, 40 (11):  1741-1748.  DOI: 10.1016/S1872-2067(19)63348-6 Abstract ( 45 )   [Full Text(HTML)] () PDF (1832KB) ( 347 )   Supporting Information Cu/ZrO2/SiO2 are efficient catalysts for the selective hydrogenation of CO2 to CH3OH. In order to understand the role of ZrO2 in these mixed-oxides based catalysts, in situ X-ray absorption spectroscopy has been carried out on the Cu and Zr K-edge. Under reaction conditions, Cu remains metallic, while Zr is present in three types of coordination environment associated with 1) bulk ZrO2, 2) coordinatively saturated and 3) unsaturated Zr(IV) surface sites. The amount of coordinatively unsaturated Zr surface sites can be quantified by linear combination fit of reference X-Ray absorption near edge structure (XANES) spectra and its amount correlates with CH3OH formation rates, thus indicating the importance of Zr(IV) Lewis acid surface sites in driving the selectivity toward CH3OH. This finding is consistent with the proposed mechanism, where CO2 is hydrogenated at the interface between the Cu nanoparticles that split H2 and Zr(IV) surface sites that stabilizes reaction intermediates.

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Using density functional calculations to elucidate atomic ordering of Pd-Rh nanoparticles at sizes relevant for catalytic applications Lorena Vega, Hristiyan A. Aleksandrov, Konstantin M. Neyman 2019, 40 (11):  1749-1757.  DOI: 10.1016/S1872-2067(19)63362-0 Abstract ( 37 )   [Full Text(HTML)] () PDF (1385KB) ( 257 )   Pd-Rh nanoparticles are known to easily undergo surface restructuring in reactive environment. This study quantifies, with the help of density functional (DFT) calculations and a novel topological approach, atomic ordering and surface segregation effects in Pd-Rh particles with compositions 1:3, 1:1 and 3:1 containing up to 201 atoms (ca. 1.7 nm). The obtained data are used to reliably optimise energetically preferred atomic orderings in inaccessible by DFT Pd-Rh particles containing thousands of atoms and exhibiting sizes exceeding 5 nm, which are typical for catalytic metal particles. It is outlined, how segregation effects on the surface arrangement of Pd-Rh nanoalloy catalysts induced by adsorbates can be evaluated in a simple way within the present modelling setup.

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Alumina-boron catalysts for oxidative dehydrogenation of ethylbenzene to styrene: Influence of alumina-boron composition and method of preparation on catalysts properties Nagaraju Pasupulety, Muhammad A. Daous, Abdulrahim A. Al-Zahrani, Hafedh Driss, Lachezar A. Petrov 2019, 40 (11):  1758-1765.  DOI: 10.1016/S1872-2067(19)63432-7 Abstract ( 51 )   [Full Text(HTML)] () PDF (1186KB) ( 273 )   Different mole ratio Al-B catalysts (Al-10B to Al-35B) were synthesized by using sol-gel (SG) method. Ethyl benzene (EB) dehydrogenation in the presence of oxygen and water steam was carried out on these catalysts at 450-500℃ with EB contact time of 0.54 gcat.s.cm-3. Acidity of Al-B catalysts was estimated by using NH3-TPD-mass spectral analysis studies. SEM-mapping images revealed fine distribution of boron up to 15% of its loading in alumina (Al-15B), whereas, boron aggregation was observed in higher boron content (Al-25B and Al-35B) catalysts. Essentially, acid sites of very weak strength (Tmax ≤ 125℃) were observed for Al and Al-10B catalysts and resulted in low EB conversion and styrene yield. On the other hand, acid sites of weak strength (Tmax ≤ 180℃) were observed for Al-25B and Al-35B catalysts and resulted in high EB conversion. However, greater styrene yield (43.2%) with reasonable EB conversion (46%) was obtained on acid sites of weak moderate strength in Al-15B catalyst. Further, Al-15B catalyst was synthesized by using co-precipitation (COP) and impregnation (IMP) methods. Acid sites related to NOx formation during the NH3-TPD-mass analysis on IMP and COP catalyst essentially improved the EB conversion to 66% and 63% respectively at 500℃. However, these acid sites were diminished in Al-B SG catalyst and resulted in 50% of EB conversion at 500℃. At 50% of EB conversion level, styrene selectivity of 73%, 82.5% and 84% were observed on Al-B IMP, Al-B COP and Al-SG catalysts, respectively. Hence, different method of preparation of Al-B catalyst generated acid sites of different strength and density and thereby influenced the styrene formation.

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Ethene and butene oligomerization over isostructural H-SAPO-5 and H-SSZ-24: Kinetics and mechanism Christian Ahoba-Sam, Marius Westgard Erichsen, Unni Olsbye 2019, 40 (11):  1766-1777.  DOI: 10.1016/S1872-2067(19)63426-1 Abstract ( 91 )   [Full Text(HTML)] () PDF (945KB) ( 307 )   Supporting Information Brønsted-acidic zeolite and zeotype materials are potential catalysts for the conversion of ethene to higher alkenes. In this study, two materials with AFI structure but different acid strength, H-SAPO-5 and H-SSZ-24, were subject to studies of ethene, cis-2-butene and ethene-butene mixture conversion under conditions where C3-C5 alkene formation is thermodynamically favoured over higher hydrocarbons (673-823 K, 1 atm). Ethene and cis-2-butene partial pressures were varied in the range 9-60 and 0.9-8.1 kPa, respectively, and contact times were varied in the range 3.78-756 and 0.573-76.4 s.μmol H+/cm3 over H-SAPO-5 and H-SSZ-24, respectively. Less than 1% conversion of ethene and less than 10% conversion of butene was obtained in the range of conditions used for elucidation of rate parameters. The ethene conversion rates were more than an order of magnitude higher over the more acidic H-SSZ-24 than over H-SAPO-5 (6.5 vs. 0.3 mmol/mol H+.s at 748 K, Pethene=33 kPa), with corre-sponding lower reaction order in ethene (1.5 vs. 2.0 at 673 K) and lower apparent activation energy (52 vs. 80 kJ/mol at 698-823 K). Propene selectivity was substantially higher over H-SSZ-24 than over H-SAPO-5 (68% vs. 36% at 0.5% ethene conversion). A similar difference in apparent reaction rates was observed for cis-2-butene conversion over the two catalysts, and for co-feeds of ethene and cis-2-butene. However, the cis-2-butene conversion to C3-C5 alkenes was found to be severely influenced by thermodynamic limitations, impeding a detailed kinetic analysis, and leading predominantly to isobutene formation at the highest temperatures.

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Reflux-synthesized bulk and diluted W-Nb-O mixed oxide bronzes for the valorization of short-chain oxygenates aqueous mixtures D. Delgado, A. Fernández-Arroyo, N. La Salvia, M. E. Domine, Jose M. López Nieto 2019, 40 (11):  1778-1787.  DOI: 10.1016/S1872-2067(19)63419-4 Abstract ( 62 )   [Full Text(HTML)] () PDF (1173KB) ( 248 )   Supporting Information This work reports the preparation of bulk and KIT-6-diluted W-Nb-O mixed oxide bronzes by a reflux method. The influence of the incorporation of Nb and a mesoporous silica on the physico-chemical features of the catalysts is studied. The addition of Nb favors the formation of single-phase oxide bronze structure, with improved Lewis acidity; while the incorporation of KIT-6 gives rise to well-dispersed mixed metal oxide particles on the diluter. These diluted W-Nb-O catalysts present enhanced surface areas and mesopore volumes. The materials have been tested in the valorization of an aqueous model mixture (acetol/propanal/ethanol/acetic acid/water weight ratio of 5/25/10/30/30), through C-C bond formation reactions. The increase in the Lewis nature of surface acid sites stands as the key point to maximize the total organic yield during the reaction (C5-C10 products). The best catalysts maintain their catalytic behavior after five consecutive uses.

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Some insight on the structure/activity relationship of metal nanoparticles in Cu/SiO2 catalysts Nicola Scotti, Elisabetta Finocchio, Claudio Evangelisti, Marcello Marelli, Rinaldo Psaro, Nicoletta Ravasio, Federica Zaccheria 2019, 40 (11):  1788-1794.  DOI: 10.1016/S1872-2067(19)63392-9 Abstract ( 60 )   [Full Text(HTML)] () PDF (685KB) ( 279 )   The activity of two Cu/SiO2 catalysts prepared by the chemisorption hydrolysis technique has been tested in the hydrogenation reaction of 3-methyl-cyclohexanone. Both catalysts were found to be very active at 60℃ and 1 atm of H2. Characterization of the materials by FT-IR of adsorbed CO and TEM put in light the presence of well formed Cu cristallites. By assuming a cuboctahedral model we could show that the hydrogenation activity is linked to high coordination sites on the metal particle. A comparison is also reported with a sample prepared by ammonia evaporation that was found to be inactive in the hydrogenation reaction under the same experimental conditions.

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Methanol as hydrogen source: Chemoselective transfer hydrogena-tion of α,β-unsaturated ketones with a rhodacycle Ahmed H. Aboo, Robina Begum, Liangliang Zhao, Zahoor H. Farooqi, Jianliang Xiao 2019, 40 (11):  1795-1799.  DOI: 10.1016/S1872-2067(19)63367-X Abstract ( 106 )   [Full Text(HTML)] () PDF (633KB) ( 338 )   Supporting Information Methanol is a safe, economic and easy-to-handle hydrogen source. It has rarely been used in transfer hydrogenation reactions, however. We herein report that a cyclometalated rhodium complex, rhodacycle, catalyzes highly chemoselective hydrogenation of α,β-unsaturated ketones with methanol as the hydrogen source. A wide variety of chalcones, styryl methyl ketones and vinyl methyl ketones, including sterically demanding ones, were reduced to the saturated ketones in refluxing methanol in a short reaction time, with no need for inter gas protection, and no reduction of the carbonyl moieties was observed. The catalysis described provides a practically easy and operationally safe method for the reduction of olefinic bonds in α,β-unsaturated ketone compounds.

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Activation of small molecules over praseodymium-doped ceria Meiling Guo, Xuebin Liu, Angelo Amorelli 2019, 40 (11):  1800-1809.  DOI: 10.1016/S1872-2067(19)63369-3 Abstract ( 70 )   [Full Text(HTML)] () PDF (2362KB) ( 291 )   Praseodymium can modify the properties of ceria (CeO2), changing the electronic structure, reducibility and catalytic behavior. Oxygen vacancies in the ceria-based samples can activate C-O and C-H bonds of small molecules such as CO2 and propane. Partially reduced Pr/CeO2-x can selectively activate C-H of propane, giving a propylene selectivity of ca. 75% at a propane conversion of 5% to 10%. Excess reduction of Pr/CeO2-x induces coking reactions during propane dehydrogenation, resulting in fast catalyst deactivation.

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Oxidative esterification of acetol with methanol to methyl pyruvate over hydroxyapatite supported gold catalyst: Essential roles of acid-base properties Yan Wan, Congcong Zheng, Xianchi Lei, Mengqi Zhuang, Jinhan Lin, Wenda Hu, Jingdong Lin, Shaolong Wan, Yong Wang 2019, 40 (11):  1810-1819.  DOI: 10.1016/S1872-2067(19)63368-1 Abstract ( 53 )   [Full Text(HTML)] () PDF (1462KB) ( 297 )   Acetol is a major light oxygenate and readily produced from staged or fast pyrolysis of lignocellulose biomass. Herein we report that acetol can be selectively converted to methyl pyruvate, an important fine chemical, through oxidative esterification over Au-based catalysts. Detailed experimental studies showed that Au on amphoteric supports with appropriate strength and balanced ratio of acid and base sites can facilitate the desired oxidative-esterification pathway without accelerating undesired aldol-condensation or Cannizzaro reactions. In particular, hydroxyapatite (with a Ca/P ratio of 1.62) supported Au achieved 87% selectivity to methyl pyruvate at an acetol conversion of 62%.