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Revealing the reaction mechanism to guide the industrial production of targeted products still remains a grand challenge for catalytic cracking of light alkanes to olefins over metal‐acid bifunctional catalyst. Herein, we systematically investigated the reaction mechanism of n‐pentane cracking on the Ag/ZSM‐5 bifunctional catalyst featuring both dehydrogenation and cracking capabilities. Specifically, overall cracking network of n‐pentane was comprehensively constructed to show the roles of metal dehydrogenation sites and acid sites respectively, in which metal Ag could substitute the H of the Brønsted acid site to form the Al–O–Ag linkage with enhanced adsorption and activation of n‐pentane, while Brønsted acid site with weak acid strength relay to promote cracking reaction. Thanks to this synergy of the two active sites, the apparent activation energy of n‐pentane cracking to light olefins was decreased from 82.77 KJ/mol to 68.26 KJ/mol and the proportion of specific path (C5H12 → H2 + C5H10) in n‐pentane monomolecular cracking reaction increased from 14.62% to 69.24%. In addition, 0.57Ag/ZSM‐5 catalyst exhibited the conversion of n‐pentane up to 67.55 wt%, which improved the performance of the parent ZSM‐5 by 13.42 wt%. These analysis results of reaction mechanism may provide some insights for the rational design of catalysts and the full utilization of petrochemical resources. [ABSTRACT FROM AUTHOR]

Oxidation of renewable polyol/sugar into formic acid using molecular O2 over heterogeneous catalysts is still challenging due to the insufficient activation of both O2 and organic substrates on coordination-saturated metal oxides. In this study, we develop a defective MnO2 catalyst through a coordination number reduction strategy to enhance the aerobic oxidation of various polyols/sugars to formic acid. Compared to common MnO2, the tri-coordinated Mn in the defective MnO2 catalyst displays the electronic reconstruction of surface oxygen charge state and rich surface oxygen vacancies. These oxygen vacancies create more Mnδ+ Lewis acid site together with nearby oxygen as Lewis base sites. This combined structure behaves much like Frustrated Lewis pairs, serving to facilitate the activation of O2, as well as C–C and C–H bonds. As a result, the defective MnO2 catalyst shows high catalytic activity (turnover frequency: 113.5 h−1) and formic acid yield (>80%) comparable to noble metal catalysts for glycerol oxidation. The catalytic system is further extended to the oxidation of other polyols/sugars to formic acid with excellent catalytic performance. This work develops defective MnO2 catalysts with Frustrated Lewis Pairs through a coordination number reduction strategy to enhance the aerobic oxidation of various polyols/sugars to formic acid. [ABSTRACT FROM AUTHOR]

Engineering acid site spatial location of zeolite catalyst harbors tremendous potential to boost catalytic performance but still remains a grand challenge for aromatization reaction. Herein, we successfully manipulate acid site spatial location inside the ZSM‐5 channels to promote the hexane aromatization via the simple SiO2 coating treatment. Multi‐techniques demonstrated that the medium strong L acid in the channel originated from the Si(Al)OZn structure is mainly retained in the Zn/ZSM‐5‐Si catalyst by covering the acid sites outside the channel. Surprisingly, there is a good linear relationship between BTEX yield and this medium strong L acid content. Based on the reaction kinetics, in situ FT‐IR and theoretical calculations, it is found that the L acid with confinement effect served as the main active site could prominently enhance the cyclization of propene intermediate and the dehydrogenation of cycloalkane due to the strong affinity between the C/H and ZnOx, and control the desorption of BTEX (mainly benzene, toluene, ethylbenzene, and p‐xylene) by weakening the binding of hydrogen proton to π electrons. Compared with the ordinary Zn/ZSM‐5 catalyst, the yield of BTEX is increased by nearly 10%, and the Zn/ZSM‐5‐Si catalyst exhibits excellent anti coking deactivation ability. This strategy together with mechanistic results may pave the rational design of efficient Zn/ZSM‐5 catalysts for aromatization reaction. [ABSTRACT FROM AUTHOR]

Achieving efficient catalytic conversion over a heterogeneous catalyst with excellent resistance against leaching is still a grand challenge for sustainable chemical synthesis in aqueous solution. Herein, we devised a single‐atom Pt1/hydroxyapatite (HAP) catalyst via a simple hydrothermal strategy. Gratifyingly, this robust Pt1/HAP catalyst exhibits remarkable catalytic selectivity and catalyst stability for the selective oxidation of C2–C4 polyols to corresponding primary hydroxy acids. It is found that the Pt−(O−P) linkages with strong electron‐withdrawing function of PO43− (Pt1−OPO43− pair active site) not only realize the activation of the C−H bond, but also destabilize the transition state from adsorbed hydroxy acids toward the C−C cleavage, resulting in the sharply increased selectivity of hydroxy acids. Moreover, the strong PO43−‐coordination effect provides electrostatic stabilization for single‐atom Pt, ensuring the highly efficient catalysis of Pt1/HAP for over 160 hours with superior leaching resistance. [ABSTRACT FROM AUTHOR]

A systematic study of Au‐promoted and unpromoted Pt/MgO/SBA‐15 catalyst is developed to separate the promoter effect from electron transfer effect between Au and Pt. Multi‐characterizations revealed that Au and Pt metals in these bimetallic catalysts mainly exist in the form of alloy, and the main role of Au is to reduce the size of AuPt alloy nanoparticles, thus enhancing the adsorption and activation of intermediate products. Through the optimization of various factors (including MgO content, Au/Pt molar ratio, reaction temperature and time), the Au1Pt2/MgO/SBA‐15 (0.05) catalyst exhibits excellent catalytic activity and glyceric acid selectivity for the selective oxidation of glycerol. Density functional theory calculation confirmed that the synergistic effect between Pt and Au active sites could facilitate the oxidation of primary hydroxyl group by promoting the activation of CH bond and the oxidation of aldehyde group. The results may give insights on designing effective Pt based bimetallic catalyst for selective oxidation of glycerol. [ABSTRACT FROM AUTHOR]

A Ni 1 Co 1 O x catalyst with lattice distortions was prepared by a modified hard template method. Elemental analysis shows that Ni tends predominantly to disperse on the surfaces of the nanoparticles. Under the optimum reaction conditions (80 °C, 20 h, and 1.5 g NaOH), Ni 1 Co 1 O x catalyst could exhibit optimum catalytic performance (78.5% conversion, 66.5% GLYA selectivity, and recycling for four times). • A lattice-distorted Ni 1 Co 1 O x catalyst was synthesized by a modified hard template method. • High selectivity toward glyceric acid was obtained on the Ni 1 Co 1 O x catalyst. • Electron transfer from Ni cations to Co cations results in the generation of surface oxygen vacancies. • The oxygen vacancies of Co and Ni species promote the oxidation of glycerol to glyceric acid. Developing cheap and highly efficient catalysts for the selective oxidation of glycerol to value-added carboxylic acids still remains a challenge. Here, non-noble-metal Ni–Co oxide catalysts with lattice distortions are reported for the first time as highly efficient and stable catalysts for the oxidation of glycerol to glyceric acid. The Ni 1 Co 1 O x catalyst, prepared by a modified hard template method, exhibits superior activity (1.5 × 10−3 s−1), excellent glyceric acid selectivity (66.5%), and good stability under mild conditions (80 °C, 1 MPa O 2). Multiple characterizations demonstrated that the nanosized Ni 1 Co 1 O x catalyst (2.3 nm) contains lattice distortion Ni–Co structures with nickel-rich surfaces. This morphology induces electron transfer from Co cations (mainly Co3+) to Ni cations (mainly Ni3+), resulting in the generation of surface oxygen vacancies. Density functional theory calculations and catalytic kinetics demonstrated that oxygen vacancies on Co species could improve glyceric acid selectivity by preventing the cleavage of C C bond, and oxygen vacancies on the Ni species could promote the activation of C H bonds, which results in the exceptional catalytic performance of Ni 1 Co 1 O x. The novel Ni–Co oxide catalyst with lattice distortions synthesized here may provide some guidance for the rational design of inexpensive and highly efficient catalysts for the catalytic oxidation of biopolyols. [ABSTRACT FROM AUTHOR]

Graphical abstract In-situ coating of SBA-15 with MgO was synthesized in one-step procedure to form the mesoporous solid bases. Then, the Pt nanoparticles were loaded by NaBH 4 reduction method. Subsequently, the Pt/MgO-SBA-15 catalyst was applied to the selective oxidation of glycerol to obtain C 3 products. Highlights • Novel hybrid Pt/MgO/SBA-15 catalysts were prepared. • The Pt nanoparticles was restricted in the channel of MgO/SBA-15. • The synergistic effect between Pt and MgO enhanced glycerol oxidation activity. • Oxygen active sites of MgO promoted the dehydrogenation reaction. Abstract Enhanced metal-support interaction is the key for selective oxidation of glycerol to value-added carboxylic acids. However, the rational control of interfacial properties still remains a significant challenge. In this work, we prepared hybrid Pt/MgO/SBA-15 catalysts for the facile oxidation of glycerol to glyceric acid in the absence of liquid alkalis. It was found that the confinement effect of SBA-15 leads to restricted Pt nanoparticles in the MgO/SBA-15 channel with a unique "strip" shape. Such a morphology and the strong electron coupling effect between Pt and MgO species synergistically enhanced glycerol oxidation over Pt-MgO sites. A volcanic-shaped relationship between Mg/Si ratio and catalytic performance was established experimentally, and the Pt/MgO/SBA-15 (0.1) catalyst showed excellent combined selectivity for C 3 products (glyceric acid, glyceraldehyde and dihydroxyacetone) with a remarkable turn over frequency (TOF) of 1671.2 h−1 higher than the reported catalysts under base-free conditions. Furthermore, density functional theory (DFT) calculations confirmed that the oxidation reaction could be promoted by oxygen defects of MgO sites, resulting in a reduction of the energy barriers for C H and O H activation. These insights may provide a new way to the supported solid base catalyst design and mechanistic study. [ABSTRACT FROM AUTHOR]

The activated carbon treated at different temperatures was performed as a catalyst for the oxidation of glycerol to glycolic acid. Heat treatment at suitable temperature could promote the enrichment of ester and carboxyl functional groups with strong electronegativity, which serves as the efficient active site for the glycerol oxidation. Therefore, the optimal AC-400 catalyst with more ester and carboxyl groups shows excellent catalytic activity (0.0039 mol/g Cat /h) and GLYOA selectivity (53.2%). [Display omitted] • The efficient oxidation of glycerol to glycolic acid was realized over heat treated activated carbon. • Heat treatment tuned the composition and electronic structure of oxygen-containing functional groups. • The ester and carboxyl functional groups with strong electronegativity enhanced the adsorption and activation of glycerol. Exploring efficient and cheap catalyst for the selective oxidation of glycerol to valuable carboxylic acids is a critical and complicated challenge. Herein, we innovatively realized the efficient oxidation of glycerol to glycolic acid over metal-free catalyst under mild conditions via carbon material defect engineering. Multiple characterizations revealed that the stepwise functionalization of active carbon caused by simple high temperature control is adopted to fine-tune the composition and electronic structure of oxygen-containing functional groups. Specifically, the abundant ester and carboxyl functional groups exhibit stronger electronegativity than the hydroxyl group, and this enhanced electronic coupling effect strengthens the adsorption of glycerol, thus improving the catalytic activity. Kinetic analysis and density functional theory calculations demonstrated that the oxygen-containing functional groups (mainly ester and carboxyl) could promote the C–H bond activation of RCH 2 O* intermediate and once C–C bond cleavage of glyceric acid, ensuring the high selectivity of glycolic acid (53.2% over AC-400 catalyst). We anticipate that this work could sheds some light on the application and design of more new type of carbon-based metal-free catalysts in the aqueous phase oxidation of various polyols. [ABSTRACT FROM AUTHOR]

Tailoring the hydrodeoxygenation capacity via the regulation of the electronic structure of the active site is still a significant challenge for hydrogenation of oxygenated substrates. Herein, we report the highly efficient bimetallic CoNi/HAP catalysts to promote the catalytic transfer hydrodecarbonylation of methyl stearate to heptadecane. Multiple characterizations reveal that the CoNi alloy nanoparticles with fcc structure exhibit strong electron coupling effect and enhanced adsorption of methyl stearate, leading to the improvement of catalytic activity. Specifically, the introduction of Ni changes the reaction pathway from methyl stearate → octadecanol over the Co/HAP catalyst to methyl stearate → heptadecane over CoNi/HAP catalysts. In situ Fourier transform infrared spectra, reaction kinetics and density functional theory calculation show that the heptadecane is mainly generated through hydrodecarbonylation (-CO) rather than hydrodecarboxylation (-COO) because the C C bond cleavage of oxygenated intermediate (RCH 2 CO) is greatly facilitated over the Ni active site of electron reconstructed CoNi alloy nanoparticles. Finally, the Co 5 Ni 5 /HAP catalyst exhibits excellent conversion (99.4%), heptadecane selectivity (98.2%) and catalyst stability. These insights revealed here could pave the way for the rational development of catalyst with high catalytic performance in the catalytic transfer hydrogenation system of fatty acids/esters. The introduction of Ni strengthens the electron coupling effect of the CoNi alloy nanoparticles, and promotes the adsorption of MS/SA, resulting in the improvement of catalytic activity. During the hydrogenation process, Co metal active site promotes the formation of oxygen-containing intermediates before octadecanol, and the as-formed C C bond of the oxygenated intermediate (RCH 2 CO) tends to be activated on the Ni active site of CoNi alloy nanoparticles, leading to the high HP selectivity. Finally, the Co 5 Ni 5 /HAP catalyst exhibits excellent conversion (99.4%), heptadecane selectivity (98.2%) and catalyst stability. [Display omitted] • Bimetallic CoNi/HAP catalysts could promote the catalytic transfer hydrodecarbonylation of methyl stearate to heptadecane. • fcc -type CoNi alloy nanoparticles exhibit strong electron coupling effect and enhanced the adsorption of methyl stearate. • Reaction pathway of catalytic transfer hydrogenation of methyl stearate to heptadecane is greatly promoted. • C-C bond cleavage of RCH 2 CO intermediate is greatly facilitated over the surface of electron reconstructed CoNi alloy. • Excellent conversion and heptadecane selectivity were obtained on the Co 5 Ni 5 /HAP catalyst. [ABSTRACT FROM AUTHOR]

The reduction reaction of carbon dioxide (RR -CO 2) to CH 3 OH using metal catalysts can reduce the energy required by this process. In this study, we investigated the RR -CO 2 mechanisms with Cu-, Ni-, and Mn-doped carbon nanotubes (CNTs). The substitutional (doping with carbon atom) positions in CNTs are suitable sites for adsorbing Cu, Ni, and Mn metals. The reaction paths to the RR -CO 2 were investigated in the gas and solvent phases. The results demonstrated that the overpotential values with Cu-, Ni-, and Mn-doped CNT(8, 0) and CNT(6, 6) catalysts in the gas and solvent phases were lower than that obtained with metal catalysts in previous studies (−1.116 V). Thus, metal-doped CNT(8, 0) and CNT(6, 6) catalysts with low overpotentials could be applied in the RR -CO 2. • Potential of nano-structures to RR- CO 2 is examined. • Possible reaction mechanisms for CO 2 reduction to CH 3 OH are investigated. • Over potential of RR- CO 2 on nano-structures are lower than metal catalysts. • Nano-structures are proposed as efficient catalysts for RR- CO 2. [ABSTRACT FROM AUTHOR]

The discharge of spent sulfuric acid generates significant toxic wastes and poses serious hazards to the environment. The effective treatment of spent sulfuric acid remains a great challenge because conventional thermochemical pyrolysis is limited by energy-intensive processing, high equipment investment, and severe equipment corrosion. In this study, we propose an energy-efficient and moderate catalytic oxidation reaction to treat spent sulfuric acid. During the catalytic oxidation reaction, the organic pollutants, especially refractory acid-soluble oil (ASO), in the conversion of spent sulfuric acid and ammonia wastewater were oxidized and degraded into CO 2 , H 2 O, and inorganic structures with H 2 O 2 as the oxidant and ozone-treated activated carbon (OAC), derived from coconut shells, as a catalyst. The catalytic activity of OAC enhanced the degradation efficiency of organic pollutants under mild conditions, which was ascribed to the abundant acidic functional groups, and the anchored metal ions on the OAC promoted the generation of highly reactive radicals. The purified (NH 4) 2 SO 4 solution with an ASO removal of 96.4% and total organic carbon (TOC) removal of ~92% under the optimum conditions was used to prepare the qualified (NH 4) 2 SO 4 product. This work demonstrates the effective utilization of spent sulfuric acid and a cost-effective route to prepare catalysts from agricultural waste for the oxidative degradation of organic pollutants. [Display omitted] • A catalytic oxidation reaction was proposed to treat spent sulfuric acid. • Agricultural waste-derived catalyst (OAC) activated the oxidation of organics. • OAC with abundant acidic functional groups exhibited excellent catalytic activity. • The adsorbed metal ions on OAC promoted H 2 O 2 to generate reactive radicals. [ABSTRACT FROM AUTHOR]

A Ph3P-catalyzed [3+2] cycloaddition of 2-phenyl-4-arylidene-5(4H)-oxazolones with benzyl 2,3-butadienoate has been developed for the efficient synthesis of structurally diverse and conformationally constrained aspartic acid analogues. [ABSTRACT FROM AUTHOR]

Ni 10 La x /MAO catalysts with high Ni dispersion was prepared by wet impregnation method. Characterization results showed that metal dispersion of Ni obviously improved on catalyst surface after La doping. Under the long-term reaction conditions (800 °C, 10 h), Ni 10 La 5 /MAO catalyst could exhibit the highest catalytic performance (93% of CH 4 conversion, 71% of CO 2 conversion and less than 3% activity loss) with lower Ni particle size (12.6 nm) and carbon deposition (8.9 %). [Display omitted] • La doping significantly increased the content of active species Ni0. • High dispersion of Ni species efficiently inhibited the growth of carbon. • Ni 10 La 5 /MgAl 2 O 4 catalyst owned the highest catalytic activity and stability in methane bi-reforming system. Ni-based catalysts were widely studied for methane reforming system in the past decades, while catalytic deactivation by carbon deposition and metal sintering limited its industrial application life. In this work, La-promoted Ni/MgAl 2 O 4 catalysts were investigated over methane bi-reforming reaction, and significantly improved the activity and stability of catalysts. Multiple characterizations showed that the introduction of La increased the content and dispersion of active species (Ni0), providing sufficient sites for methane adsorption and dissociation. Besides, smaller particle size of active metal (12.6 nm) was proved to inhibiting carbon accumulation on catalyst surface. Ni 10 La 5 /MgAl 2 O 4 catalyst was found to exhibit the highest catalytic performance (93% of CH 4 conversion, 71% of CO 2 conversion and less than 3% activity loss) under long-term reaction conditions (800 °C, 10 h). This work will provide important guiding significance for the design of high-efficiency methane reforming catalysts. [ABSTRACT FROM AUTHOR]

We successfully realized the highly selective aromatization of n-hexane by the assistance of CO 2 over Zn modified HZSM-5 catalyst. The in situ H originated from the C-H activation of n-hexane and cyclohexane could be timely removed through the dynamic evolution between CO 2 and Lewis acid site, thus inhibiting the hydrogen transfer side reaction and promoting the desorption of BTEX. Therefore, the Zn/ZSM-5-CO 2 catalyst exhibits as high as 49.7% BTEX yield, which is nearly 10% higher than that of the Zn/ZSM-5-N 2 catalyst (40.3%). [Display omitted] • The introduction of CO 2 could timely remove the in situ H. • Hydrogen transfer between olefins and aromatics is effectively inhibited. • The binding of hydrogen proton to π electrons is weakened. • The loss of medium strength Lewis acid is significantly reduced. • The Zn/ZSM-5-CO 2 catalyst exhibits as high as 49.7% BTEX yield and superior catalytic stability. Controlling the evolution of H species in CO 2 -assisted alkane activation represents an opportunity for simultaneously upgrading light alkanes and greenhouse gas CO 2. Herein, we successfully realized the highly selective aromatization of n -hexane by the assistance of CO 2 over Zn modified HZSM-5 catalyst. Multi-characterizations demonstrated that the introduction of CO 2 could timely remove the in situ H originated from the C-H activation of n -hexane and cyclohexane through the dynamic evolution of the pentagonal coordination Zn-OH+-(CO)-O-Zn structure. On this basis, hydrogen transfer between olefins and aromatics is effectively inhibited, and the binding between π electrons of benzene ring and hydrogen proton is weakened, accelerating the generation and desorption of BTEX. Therefore, the Zn/ZSM-5-CO 2 displays a record high 49.7% BTEX yield, which is nearly 10% higher than that of the Zn/ZSM-5-N 2 (40.3%). In addition, the loss of medium strength Lewis acid caused by in situ H reduction of Si(Al)-O-Zn structure is significantly reduced, ensuring its superior catalytic stability under long-term conditions. These results may provide some insights for the profitable utilization of petrochemical resources to aromatics over zeolites. [ABSTRACT FROM AUTHOR]

The 1R-alkoxygenipins exhibit significantly enhanced bioactivity in comparison to their S-isomers; however, the challenge lies in the selective synthesis of these compounds. A streamlined and highly effective approach to achieve stereoselective 1R-alkyloxygenipins involved the use of a carefully balanced mixture of Lewis acid catalytic reagents, specifically BF 3 ·Et 2 O and H 2 O. This method emerged as the optimal choice after evaluating various synthetic routes, encompassing 1-OH and 10-OH substitutions, different Lewis acids, and their respective ratios as catalysts. The possible mechansim of the catalyst for genipin was investigated. Particularly, the method with non-strict conditions for the synthesis of 1R-alkoxygenipins was underscored by its operational simplicity, stability, and low energy consumption. This approach not only streamlined the synthetic process but also established a robust foundation for future bioactivity studies on 1R-alkyloxygenipins. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • C/Sn 2 S 3 /S is obtained by loading sulfur on the surface of C/Sn. • C/Sn 2 S 3 /S composite electrodes possess good rate performance in Li-S batteries. • Sn atom modified carbon can achieve stable polysulfide conversion process. Dissolution of polysulfides limits the improvement of rate performance in Li-S batteries. Introducing catalytic agents is the key to promote polysulfide conversion process and improve rate performance of Li-S batteries. Both metallic atoms catalysts and metal sulfide catalysts can promote polysulfide conversion process. However, the comparison of catalyzing abilities between metallic atoms catalysts and metal sulfide catalysts in Li-S batteries still needs to be studied. SnS modified carbon (C/SnS) and Sn atom modified carbon (C/Sn) are obtained by controlling hydrothermal and carbonization processes in this paper. Electrochemical performance of C/SnS/S and C/Sn 2 S 3 /S composite electrodes are also studied, which are obtained by loading sulfur on C/SnS and C/Sn. Results show that C/Sn 2 S 3 /S composite electrodes possess higher rate performance (553 mAh·g−1 at 5C) than C/SnS/S composite electrodes, which is ascribe to stable catalyzing abilities of Sn atom modified carbon. Electron transportation abilities and Li-ion diffusion process are both promoted in C/Sn 2 S 3 /S composite electrodes. The comparison of catalyzing abilities between C/SnS and C/Sn composites provides reference for design and regulation of composite structures. [ABSTRACT FROM AUTHOR]

• Na+ is introduced to Mo/ZSM-5 via post-impregnation to maintain Mo-dispersion. • Bronsted acids are exclusively regulated to investigate the influence. • Coke and naphthalene are suppressed after introducing Na+. • MDA reaction is found to follow mono-functional pathway. • Confined hydrocarbon pool serves as precursors for both aromatics and coke. Methane dehydroaromatization is a potential technique in converting natural gas into value-added aromatics and clean hydrogen. However, severe coking hinders industrial application of conventionally prepared Mo/ZSM-5 catalyst for methane dehydroaromatization. Usually, Bronsted acid sites (BAS) were considered the key for coking. To gain deeper insight into the coke, here we present a simple post-impregnation of Na+ to Mo/HZSM-5 to regulate its surface acidity. Influences of BAS on catalytic performance and coking behavior were thus exclusively studied. Na+ modified catalysts exhibit lower naphthalene and higher C2 selectivity, while selectivity for benzene is not obviously changed. These results contradict conventional bi-functional pathway that methane is dehydrogenated on Mo while BAS act as the center for intermediates cyclization. Characterizations and calculations indicate restricted growth of hydrocarbon pools confined in zeolite channels of Na+ modified catalysts. Hence, it is proposed that aromatization is the intrinsic property of Mo, and the Mo-associated carbonaceous species act as precursors for both coke and aromatics production. [ABSTRACT FROM AUTHOR]

[Display omitted] • A method to control the surface Mo:C ratio by carbonization flow is discovered for the first time. • The relationship between the surface Mo:C ratio and the reactivity is established. • The low temperature water gas shift reaction activity depends on the electron transfer capability of the surface. • The catalysts with low Mo:C ratio improve catalyst stability. The low-temperature water–gas shift (WGS) reaction is an important industrial process for producing hydrogen and reducing carbon dioxide emissions. The α-MoC 1-x catalysts have shown promising performance in WGS reactions, but their activities are highly dependent on the surface structure. In this study, we investigated the effect of surface Mo and C ordinations on the low-temperature WGS activity of Pt/α-MoC 1-x catalysts using both experimental and theoretical methods. Our results reflected that as Mo: C ratio decreases, the surface free carbon and reduced number of Mo active sites led to a weakened electron transfer ability, resulting in poor catalytic activity. The 0.4% Pt/α-MoC 1-x -50 catalyst displayed superior hydrogen production activity and low apparent activation energy (E app = 58.5 kJ/mol) at low temperatures (100–200 °C). Our density functional theory (DFT) calculations revealed that the high reactivity of the 0.4% Pt/α-MoC 1-x -50 catalyst was due to the strong electron transfer capability and increased number of surface Mo active sites. This study provides new insights into the structure–activity relationship and stability of α-MoC 1-x catalysts for the WGS reaction and lays the foundation for the design of WGS catalysts with high activity and stability at low temperature. [ABSTRACT FROM AUTHOR]

On the basis of benzoxazine chemistry, we have established a new way to synthesize highly uniform carbon nanospheres with precisely tailored sizes and high monodispersity. Using monomers including resorcinol, formaldehyde, and 1,6-diaminohexane, and in the presence of Pluronic F127 surfactant, polymer nanospheres are first synthesized under precisely programmed reaction temperatures. Subsequently, they are pseudomorphically and uniformly converted to carbon nanospheres in high yield, due to the excellent thermal stability of such polybenzoxazine-based polymers. The correlation between the initial reaction temperature (IRT) and the nanosphere size fits well with the quadratic function model, which can in turn predict the nanosphere size at a set IRT. The nanosphere sizes can easily go down to 200 nm while retaining excellent monodispersity, i.e., polydispersity <5%. The particle size uniformity is evidenced by the formation of large areas of periodic assembly structure. NMR, FT-IR, and elemental analyses prove the formation of a polybenzoxazine framework. As a demonstration of their versatility, nanocatalysts composed of highly dispersed Pd nanoparticles in the carbon nanospheres are fabricated, which show high conversion and selectivity, great reusability, and regeneration ability, as evidenced in a selective oxidation of benzyl alcohol to benzaldehyde under moderate conditions. [ABSTRACT FROM AUTHOR]