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Bimetallic PtSn catalysts with notable activity and selectivity are widely used in propane dehydrogenation to propylene. However, at high temperature, catalysts are prone to carbon deposition, leading to a decrease in stability. CO2-oxidative propane dehydrogenation (CO2-PDH) has become a new research hotspot due to its potential to eliminate carbon deposition and promote the forward movement of dehydrogenation reaction while converting propane. The reverse water-gas shift catalyst β-Mo2C with propane dehydrogenation catalyst PtSn@S-1 were mixed in CO2-PDH, aiming to develop highly active, selective and stable catalysts. The catalysts were characterized by XRD, CO2-TPD, C3H6-TPD, and thermogravimetric analysis. The research results indicate that in CO2-PDH, the stability of the powder-mixed tandem catalyst PtSn@S-1& β-Mo2C significantly improves by adding β-Mo2C in series to PtSn@S-1, and the catalyst remains active without deactivation during continuous operation for 1440 min, and the high stability of the catalyst is attributed to the removal of partial carbon deposition by CO2 during the reaction process. After optimizing the reaction conditions, it is found that when n(CO2): n(C3H8) is 1.0 and m(PtSn@S-1):m(β-Mo2C) is 1.0: 0.4, the powder-mixed tandem catalyst PtSn@S-1& β-Mo2C exhibites the best performance in CO2-PDH. The propane conversion rate remains stable at above 43.0% after 500 min and propylene selectivity exceeds 99%. [ABSTRACT FROM AUTHOR]

The most widely used catalyst for the hydrogen evolution reaction (HER) is Pt, but the high cost and low abundance of Pt need to be urgently addressed. Single-atom catalysts (SACs) have been an effective means of improving the utilization of Pt atoms. In this work, we used a nonmetal (NM = B, N, O, F, Si, P, S, Cl, As, Se, Br, Te, and I) doped β-Mo 2 C (100) C-termination surface as the support, with Pt atoms dispersed on the support surface to construct Pt@NM-Mo 2 C. Using density functional theory (DFT) calculations, we selected catalysts with excellent HER activity. Among 117 candidate catalysts, 49 catalysts exhibited ideal catalytic performance with Gibbs free energy of hydrogen intermediate (H*) adsorption (Δ G H* ) values less than 0.2 eV. The Δ G H* values of 16 catalysts were even lower than that of Pt (Δ G H* ≈ 0.09 eV), with Pt I @N 2/4-a -Mo 2 C demonstrating the best performance (Δ G H* = -0.01 eV). Combined with electronic structure analysis, we could understand the impact of charge transfer between Pt and the underlying NM atoms on the strength of the Pt-H bond, thereby promoting HER activity. Using machine learning (ML), we identified that the primary influencing factors of the HER catalytic activity in the Pt@NM-Mo 2 C system were the Bader charge transfer of Pt ( N ePt ), the d-band center of Pt (ε dPt ), and the atomic radius of NM ( R NM ), with N ePt having the greatest impact on the HER catalytic activity.

The advancement of innovative Mo 2 C anode yet faces the challenge of exploring a simple, convenient and controllable synthetic route. β-Mo 2 C was prepared by utilizing low-cost hexamethylenetetramine and ammonium molybdate as raw materials and employing simple calcination treatment under N 2 atmosphere. When applied as an anode for lithium ion batteries (LIBs), β-Mo 2 C delivers a satisfactory rate performance (147.0 and 103.4 mAh g−1 at 0.5 and 1.0 A g−1) and excellent cyclic stability (72.2 mAh g−1 at 2.0 A g−1 after 1500 cycles). Meanwhile, a suitable voltage plateau at ∼1.4 V for β-Mo 2 C also avoids the formation of lithium dendrites to improve the safety of LIBs. β-Mo 2 C with high electronic conductivity and suitable lithium storage potential was prepared by utilizing low-cost hexamethylenetetramine and ammonium molybdate as raw materials and employing simple calcination treatment under N 2 atmosphere. [Display omitted] • β-Mo 2 C was prepared by simple calcination treatment under N 2 atmosphere. • A suitable voltage plateau (∼1.4 V) for β-Mo 2 C avoids the formation of Li dendrite. • β-Mo 2 C delivered a satisfactory rate performance and excellent cyclic stability. [ABSTRACT FROM AUTHOR]

The CO 2 -assisted oxidative dehydrogenation reaction can possibly become a more sustainable alternative for the production of light olefins. Due to the endothermic nature of this reaction, elevated reaction temperatures are required to achieve conversion levels of interest, with competing side reactions as result. In this study, the effect of reaction temperature on the performance of silica supported molybdenum carbide nanoparticles is investigated. At all applied reaction temperatures, the maximum possible ethylene selectivity of 67 C-% is achieved. An increase in reaction temperature decreases the oxidation of the catalyst under reaction conditions. However, a clear phase change effect on the various carbide allotropes suggests that an oxidation/re-carburization mechanism occurs from β-Mo 2 C to MoO x C y /MoO 2 to α-MoC 1−x /β-Mo 2 C, rather than a prevention of the oxidation in the first place. Nevertheless, catalyst deactivation was still observed and can be assigned to carbon formation on the surface of the catalyst, blocking active sites. [Display omitted] • Mo 2 C on SiO 2 performs CO 2 -ODH with minimal occurrence of side reactions. • Severe oxidation of β-Mo 2 C to MoO 2 during low temperature CO 2 -ODH. • High temperature CO 2 -ODH re-carburizes MoO 2 to MoO x C y followed by α-MoC 1−x. • Extensive characterization of spent catalyst using XRD, XANES and Raman. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) coupled with catalysis provides a way to enable the dry reforming of methane (DRM) reaction to occur at low temperatures. While assistance of NTP brings the negative issue of coke deposition due to the faster rate of CH 4 dissociation induced by NTP. Herein, β-Mo 2 C was employed as an effective component to activate CO 2 and collaborated with Ni/γ-Al 2 O 3 for the plasma-assisted DRM reaction. Addition of β-Mo 2 C facilitated the charge deposition, and Ni nanoparticles were found to re-disperse over the β-Mo 2 C surface due to the strong interaction between Ni and β-Mo 2 C. Benefiting from the new active interface of Ni-Mo 2 C, the mechanically mixed Mo 2 C-Ni/Al 2 O 3 catalyst exhibited much better activity and stability as compared with the undoped Ni/Al 2 O 3 catalyst. The present study reveals the crucial roles of β-Mo 2 C additives, providing practical solutions to depress carbon deposition, and thereby enhance the catalytic stability in plasma-assisted DRM reaction. [Display omitted] • β-Mo 2 C collaborated with Ni/γ-Al 2 O 3 for the coupled plasma-catalysis DRM reaction. • β-Mo 2 C facilitated the charge deposition and higher energy efficiency being obtained. • Redispersion of Ni NPs over β-Mo 2 C forming Ni-Mo 2 C interface. • A matching conversion rate of CH 4 with that of CO 2 being obtained. [ABSTRACT FROM AUTHOR]

• Molybdenum carbides of different crystal phases have been prepared and experimentally compared. • Molybdenum carbide exhibited excellent aromatics selectivity in quinoline hydrodenitrogenation, and this catalytic process was characterized by low hydrogen consumption. • The excellent performance of the catalyst was explained from the perspective of characterization and density functional theory. • The hypothesis of multiple active sites on molybdenum carbide was proposed. The hydrodenitrogenation (HDN) with a low hydrogen consumption in the hydroprocessing of crude oils derived from carbon resources is still a challenge. Here, a molybdenum carbide (α-MoC 1-x) catalyst with a high selectivity to aromatic compounds was reported, using the HDN of quinoline as a model reaction. This process was characterized by low hydrogen consumption. The prepared α-MoC 1-x had a much larger specific surface area (107.6 m2•g−1) than β-Mo 2 C (6.8 m2•g−1). Under the catalysis of α-MoC 1-x , the conversion and the denitrification rate of quinoline could both reach 99%, and the highest selectivity of the total aromatics reached 48.5% at 360 °C, which was 10.7% higher than that on β-Mo 2 C. The cleavage of C C bonds of side chain of Propylbenzene (PB) and Propylcyclohexane (PCH) occurred, producing several unexpected products with unusual high selectivity. A new possible reaction network of quinoline hydrodenitrogenation was drawn, and the reaction mechanism was discussed based on the experiments and DFT (density functional theory) calculations. [Display omitted] [ABSTRACT FROM AUTHOR]