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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]

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]

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]

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]

[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]