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Tuning CO2 hydrogenation selectivity to obtain targeted value‐added chemicals and fuels has attracted increasing attention. However, a fundamental understanding of the way to control the selectivity is still lacking, posing a challenge in catalyst design and development. Herein, we report our new discovery in ambient pressure CO2 hydrogenation reaction where selectivity can be completely reversed by simply changing the crystal phases of TiO2 support (anatase‐ or rutile‐TiO2) or changing metal loadings on anatase‐TiO2. Operando spectroscopy and NAP‐XPS studies reveal that the determining factor is a different electron transfer from metal to the support, most probably as a result of the different extents of hydrogen spillover, which changes the adsorption and activation of the intermediate of CO. Based on this new finding, we can not only regulate CO2 hydrogenation selectivity but also tune catalytic performance in other important reactions, thus opening up a door for efficient catalyst development by rational design. [ABSTRACT FROM AUTHOR]

Strong metal–support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single‐atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2‐supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18‐electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3‐nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI. [ABSTRACT FROM AUTHOR]

Strong metal–support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single‐atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2‐supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18‐electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3‐nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI. [ABSTRACT FROM AUTHOR]

• Ruthenium nanoparticles incorporated in mesoporous carbon are reported for production of γ-valerolactone. • The incorporated catalysts demonstrate excellent reusability and thermal stability. • Leaching can be minimised by tailoring the mesoporous structure. • The mechanism of high reusability and thermal stability for incorporated ruthenium catalysts are studied. The hydrogenation of levulinic acid to γ-valerolactone with water as solvent is a crucial reaction for producing fine chemicals. However, the development of highly stable catalysts is still a major challenge. Here, we prepared a Ru nanoparticles incorporated in mesoporous-carbon (Ru-MC) catalyst to achieve high stability in acidic aqueous medium. The Ru-MC showed excellent catalytic performance (12024 h−1 turnover frequency) in the hydrogenation of LA-to-GVL. Compared with Ru supported on mesoporous carbon catalyst (Ru/MC) prepared by conventional wet impregnation method, the Ru-MC showed excellent reusability (more than 6 times) and thermal stability (up to 600 °C). Based on H 2 -TPR-MS characterization, it was proposed that the incorporated structure significantly increased the interaction between Ru nanoparticles and carbon support, which effectively prevent the leaching and sintering of Ru nanoparticles and contributed to increased high reusability and thermal stability of the Ru-MC. [ABSTRACT FROM AUTHOR]

• 1 wt% Ru loaded on N-doping carbon spheres catalysts (Ru/N-CS-850) were prepared. • N-doping carbon effectively improves the dispersion of Ru nanoparticles (Ru NPs). • The quaternary N plays the conclusive role for high dispersion of Ru NPs. • Ru/N-CS-850 has the highest absolute content of quaternary N and dispersity of Ru NPs. • Ru/N-CS-850 shows excellent yield for producing γ-valerolactone in water medium. Ru/carbon catalyst has been considered as a very active catalyst in aqueous-phase hydrogenation of bio-resourced carbonyl compounds. High dispersion of Ru NPs on a carbon support could enhance catalytic performance. In this work, well dispersed Ru nanoparticles on the surface of carbon spheres have been developed by the introduction of nitrogen-doping. Compared with carbon spheres without N-doping, the incorporation of the N-dopant with in the carbon matrix effectively improved the dispersion of Ru nanoparticles, which was confirmed by X-ray photoelectron spectroscopy (XPS) and CO chemisorption characterizations, finding that the presence of quaternary N was responsible for the high dispersion of Ru nanoparticles. Through adjusting the carbonization temperature from 400 to 850 °C, we have shown that the absolute content of quaternary N can be modulated from 3.2 to 22.4 mg g−1. As a result, the dispersion of Ru nanoparticles was improved from 29.8% to 70.9%. The Ru/N-CS-850 catalyst revealed excellent catalytic performance (9858 h−1 turnover frequency) for the hydrogenation of levulinic acid to γ-valerolactone, also demonstrated very high catalytic activity for other hydrogenation reactions. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermally stable, acid‐resistant nickel catalysts are highly desired in hydrogenation reactions, but such a catalyst remains absent owing to the inherent vulnerability of nickel under acidic conditions. An ultra‐durable Ni‐N‐C single‐atom catalyst (SAC) has now been developed that possesses a remarkable Ni content (7.5 wt %) required for practical usage. This SAC shows not only high activities for hydrogenation of various unsaturated substrates but also unprecedented durability for the one‐pot conversion of cellulose under very harsh conditions (245 °C, 60 bar H2, presence of tungstic acid in hot water). Using integrated spectroscopy characterization and computational modeling, the active site structure is identified as (Ni‐N4)⋅⋅⋅N, where significantly distorted octahedral coordination and pyridinic N constitute a frustrated Lewis pair for the heterolytic dissociation of dihydrogen, and the robust covalent chemical bonding between Ni and N atoms accounts for its ultrastability. [ABSTRACT FROM AUTHOR]

Copper has been reported to be active in selective hydrogenation of acetylene but very selective to oligomers instead of ethylene. In this work, SBA-15 supported Cu-Au bimetallic nanoparticles are studied under different Cu/Au ratios and temperature. The addition of gold promotes the catalytic performance, reducing the amount of oligomers formed on the catalyst's surface. A synergistic effect between copper and gold is also displayed. The bimetallic catalyst with Cu/Au ratio at 1/3 has both better conversion and selectivity between 160-200 °C, providing the opportunities to lower the operating temperature (>200 °C) of copper. The synergy can be ascribed to the compromise of two factors: the electronic effect and the sintering resistance of bimetallic nanoparticles. Gold makes copper more electron-deficient, therefore, enhances the conversion. Besides, the particles remain highly dispersed and small (ca. 3 nm) when large amount of gold reduces the ensemble size of copper on the surface, minimizing C-C coupling reactions. [ABSTRACT FROM AUTHOR]

Abstract: Supported gold nanocatalysts have been reported to be active in selective hydrogenation of acetylene. In this work, SiO2 supported Au–Ag bimetallic catalyst is studied in the selective hydrogenation of acetylene in excess ethylene. Au and Ag were reductively deposited on a silica surface functionalized by APTES (3-aminopropyltriethoxysilane). They form Au–Ag alloy nanoparticles of very small size. The catalytic activity of Au–Ag bimetallic system showed better catalytic activity at high temperature than that of monometallic gold catalyst. According to the TEM and XRD results, Ag stabilized the nanoparticles against sintering during high temperature calcinations. Non-thermal O2 plasma was applied to remove the APTES under mild conditions instead of high temperature calcination. The results showed that the conversion of acetylene was much higher over Au–Ag/SiO2 catalyst pretreated by O2 plasma than that of pretreated by calcination at 500°C, although the latter catalyst had similar particle size. [Copyright &y& Elsevier]

Abstract: Supported gold nanoparticles have been proven to be active in the hydrogenation of the acetylene. In this work, we applied gold nanoparticles supported on silica for the selective hydrogenation of acetylene in excess ethylene that was close to current industrial practices. Amine group surface-functionalized silica was used to absorb the gold precursor , and small size-controlled gold nanoparticles are formed after chemical reduction. For the first time, O2 plasma was employed to remove the APTES grafted on the surface of silica for preparing the highly dispersed gold nanoparticles (∼3nm). The results of IR, TGA, XRD, and TEM showed that O2 plasma working under mild conditions (room temperature and low pressure) can efficiently remove the organic compounds without causing the aggregation of the gold nanoparticles. The plasma-treated catalyst Au/SiO2 gave excellent low-temperature selective catalytic activity in the hydrogenation of acetylene. The effects of the reduction temperatures on the catalytic performances of the Au/SiO2 were investigated. The enhanced performance of gold nanoparticles supported on silica as pretreated by O2 plasma was ascribed to two effects: (1) the small size of the gold nanoparticles supported on silica, (2) the nearly neutral charge on the Au nanoparticle, which is favorable to the activation of hydrogen. [Copyright &y& Elsevier]

In 2 O 3 has been found a promising application in CO 2 hydrogenation to methanol, which is beneficial to the utilization of CO 2. The oxygen vacancy (O v) site is identified as the catalytic active center of this reaction. However, there remains a great challenge to understand the relations between the state of oxygen species in In 2 O 3 and the catalytic performance for CO 2 hydrogenation to methanol. In the present work, we compare the properties of multiple In 2 O 3 and Ir-promoted In 2 O 3 (Ir-In 2 O 3) catalysts with different Ir loadings and after being pretreated under different reduction temperatures. The CO 2 conversion rate of Ir-In 2 O 3 is more promoted than that of pure In 2 O 3. With only a small amount of Ir loading, the highly dispersed Ir species on In 2 O 3 increase the concentration of O v sites and enhance the activity. By finely tuning the catalyst structure, Ir-In 2 O 3 with an Ir loading of 0.16 wt.% and pre-reduction treatment under 300°C exhibits the highest methanol yield of 146 mg CH3OH /(g cat ·hr). Characterizations of Raman, electron paramagnetic resonance, X-ray photoelectron spectroscopy, CO 2 -temperature programmed desorption and CO 2 -pulse adsorption for the catalysts confirm that more O v sites can be generated under higher reduction temperature, which will induce a facile CO 2 adsorption and desorption cycle. Higher performance for methanol production requires an adequate dynamic balance among the surface oxygen atoms and vacancies, which guides us to find more suitable conditions for catalyst pretreatment and reaction. [ABSTRACT FROM AUTHOR]

It is desirable to design nonprecious metal nanocatalysts with high stability and catalytic performance for fine chemicals production. Here, a method is reported for the preparation of cobalt metal and cobalt oxide cores confined within nanoporous nitrogen‐doped hollow carbon capsules. Core–shell structured Zn/Co‐ZIF@polymer materials are fabricated through a facile coating polymer strategy on the surface of zeolitic imidazolate frameworks (ZIF). A series of hollow carbon capsules with cobalt metal and cobalt oxide are derived from a facile confined pyrolysis of Zn/Co‐ZIF@polymer. The hollow Co‐CoOx@N‐C capsules can prevent sintering and agglomeration of the cobalt nanoparticles and the nanoporous shell allows for efficient mass transport. The specific surface area and Co particle size are optimized through finely tuning the original Zn content in ZIF particles, thus enhancing overall catalytic activity. The yolk–shell structured Zn4Co1Ox@carbon hollow capsules are shown to be a highly active and selective catalyst (selectivity >99%) for hydrogenation of nitrobenzene to aniline. Furthermore, Zn4Co1Ox@carbon hollow particles show superior catalytic stability, and no deactivation after 8 cycles of reaction. The hollow Co‐CoOx@N‐C capsules may shed light on a green and sustainable catalytic process for fine chemicals production. [ABSTRACT FROM AUTHOR]

Heterogeneous single-atom catalyst (SAC) opens a unique entry to establishing structure–performance relationship at the molecular level similar to that in homogeneous catalysis. The challenge lies in manipulating the coordination chemistry of single atoms without changing single-atom dispersion. Here, we develop an efficient synthetic method for SACs by using ethanediamine to chelate Pt cations and then removing the ethanediamine by a rapid thermal treatment (RTT) in inert atmosphere. The coordination chemistry of Pt single atoms on a Fe2O3 support is finely tuned by merely adjusting the RTT temperature. With the decrease in Pt-O coordination number, the oxidation state of Pt decreases, and consequently the hydrogenation activity increases to a record level without loss of chemoselectivity. The tunability of the local coordination chemistry, oxidation states of the metal, and the catalytic performance of single atoms reveals the unique role of SACs as a bridge between heterogeneous and homogeneous catalysis. In single-atom catalysts (SACs), little is known about how the coordination structure of single atoms affects the catalytic performance. Here, the authors discover that in Pt1/Fe2O3 SAC, the coordination number of the first shell Pt-O is well correlated with the Pt electronic property and the hydrogenation activity. [ABSTRACT FROM AUTHOR]

UB3LYP computation including dispersion and toluene solvation has been carried to elucidate the mechanisms of alkene hydrogenation catalyzed by bis(imino)pyridine iron dinitrogen complex (iPrPDI)Fe(N2)2, which has low stability towards N2 dissociation. The coordinatively unsaturated complexes, (iPrPDI)Fe(N2) and (iPrPDI)Fe(1-C4H8), favor open-shell singlet ground states. On the basis of our computations, we propose a new mechanism of 1-butene coordination and hydrogenation after N2 dissociation. The hydrogenation of 1-butene undergoes a concerted open-shell singlet transition state involving H2 dissociation, C-H bond formation and C=C bond elongation, as well as the subsequent C-H reductive elimination. In the whole alkene hydrogenation, the H-H bond cleavage is the rate-determining step. Graphical abstract The alkene hydrogenation catalyzed by redox-active pyridine(diimine)-chelate iron complex follows the open-shell singlet state path [ABSTRACT FROM AUTHOR]

The cover picture shows a simple milling‐mediated solid reduction method for fabricating of ultrafine gold catalysts. By solid grinding of the N‐modified SiO2 supported Au precursors with NaBH4, subnanometer‐sized clusters and isolated Au atoms can be facilely obtained by tuning the metal loading. This method establishes a good basis for fundamental understanding the size effect of Au in the hydrogenation of CO2 to formate, and provides a general methodology for supported nano‐catalyst preparation. More details are discussed in the article by Huang et al. on page 329–332. [ABSTRACT FROM AUTHOR]

An effective solvent‐free method based on a solid‐reduction process was developed to fabricate ultrafine gold catalysts. By this method we revealed a strong size‐dependent activity of Au species in which subnanometer‐sized clusters exhibited the best activity in the hydrogenation of CO2 to formate, with a turnover number of up to 9278 over 7 h at 90 °C. [ABSTRACT FROM AUTHOR]

The highly efficient and direct asymmetric reductive amination of arylacetones catalyzed by an iridium complex for the preparation of enantiomerically pure β-arylamines is described. [ABSTRACT FROM AUTHOR]

Abstract: Mo modified Ir/SiO2 (Ir-MoOx/SiO2) was firstly used for the aqueous-phase hydrogenation of acetic acid to ethanol and exhibited the best performance among the investigated catalysts. The synergy effect between the closely contacted Ir and Mo species is responsible for the excellent performance of Ir-MoOx/SiO2. Ir-MoOx/SiO2 is also effective for the hydrogenation of other biomass derived carboxylic acids. Especially when levulinic acid was used as the feedstock, high yields of 2-pentanol (39.0%) and 1,4-pentanediol (42.3%) were obtained simultaneously. To our knowledge, this is the first report about the direct hydrogenation of levulinic acid to 2-pentanol and 1,4-pentanediol over heterogeneous catalyst. [Copyright &y& Elsevier]

Strong metal–support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single‐atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2‐supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18‐electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3‐nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI. [ABSTRACT FROM AUTHOR]

Strong metal–support interaction (SMSI) has gained great attention in the field of heterogeneous catalysis. However, whether single‐atom catalysts can exhibit SMSI remains unknown. Here, we demonstrate that SMSI can occur on TiO2‐supported Pt single atoms but at a much higher reduction temperature than that for Pt nanoparticles (NPs). Pt single atoms involved in SMSI are not covered by the TiO2 support nor do they sink into its subsurface. The suppression of CO adsorption on Pt single atoms stems from coordination saturation (18‐electron rule) rather than the physical coverage of Pt atoms by the support. Based on the new finding it is revealed that single atoms are the true active sites in the hydrogenation of 3‐nitrostyrene, while Pt NPs barely contribute to the activity since the NP sites are selectively encapsulated. The findings in this work provide a new approach to study the active sites by tuning SMSI. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenation of carbon dioxide to CO by reverse water gas shift reaction plays a vital role in the recycling of the abundant carbon source. Here, the reaction over a series of zeolite L-supported platinum catalysts was systematically investigated to study the promoting role of potassium. The results of activity tests showed that controlled addition of potassium promoter to Pt/L catalyst was beneficial for the catalytic activity and selectivity. It was observed that cage encapsulation by zeolite pores could stabilize Pt nano-particles even at severe reaction conditions. Furthermore, X-ray absorption near edge structure and X-ray photoelectron spectra results demonstrated that the chemical state of platinum was altered by the additional potassium promoter, providing evidence for the formation of Pt-O(OH)-K interfacial sites. Thereafter, the Pt-O(OH)-K interfaces, acting as main active sites to adsorb CO 2 and produce bridge-bonded formate intermediates, were identified by a set of in-situ diffuse reflectance Fourier transform infrared spectroscopy and microcalorimetry measurements. This finding provides new insights into the use of a variety of zeolite as carriers for highly dispersed noble metal in catalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

Conventional electrocatalysts underperform with reaction kinetics, nitrogen dissociation, and activated hydrogen recombination, demanding effective strategies for improving electrochemical nitrogen fixation. The challenge lies in the rational design of electron back-donating centers for nitrogen activation and hydrogen migration path optimization. This study proposes an effective laser-tuning strategy to construct noble-metal Lewis acid sites on molybdenum carbide (M-Mo 2 C, M = Ru, Rh, Pd, Ir), yielding a more active material system by mimicking π back-donation behavior. Laser-tuned Lewis acid sites can effectively break N≡N bonds, lower thermodynamic energy barrier of the rate-determining hydrogenation step (*NN → *N-NH), and optimize hydrogen migration pathway. The Rh-Mo 2 C shows superior NRR activity with NH 3 yield of ∼26.3 µg h−1 cm−2 cat. and Faradaic efficiency of ∼15.4%, which are 5.1- and 3.6-fold higher than those of Mo 2 C, respectively. This work demonstrates a unique and universal strategy for designing high-performance electrocatalysts by accurately manipulating electronic structure of active sites. [Display omitted] • A series of noble-metal-Mo 2 C with optimized interfacial microstructure was constructed by laser tuning strategy. • Low energy barrier of the rate-determining hydrogenation step (*NN → *N-NH) was achieved on Rh-Mo 2 C. • In situ characterizations and isotope labelling experiments confirmed the effectiveness of nitrogen fixation. • Noble metal Lewis acid sites effectively optimized hydrogen migration pathway to promote nitrogen fixation selectivity. [ABSTRACT FROM AUTHOR]