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To effectively utilize glycerol as a fuel for electrochemical fuel cells, it is necessary to optimize catalysts for effective C-C bond cleavage and complete oxidation of reaction intermediates to achieve maximum efficiency. The current work showed that the synergistic interactions of platinum (Pt) with transition metal carbide (TMC) substrates, such as tungsten carbide (WC) and tantalum carbide (TaC), fulfilled these criteria. The TMC-supported Pt catalysts showed higher activity and selectivity for complete glycerol oxidation than commercial 10 wt% Pt/C. In-situ FTIR analysis revealed that 5 wt% Pt/WC was the most effective catalyst among those tested for complete glycerol oxidation at 0.9 V vs RHE. In-situ X-ray absorption fine structure characterization and density functional theory calculations provided additional insight into the synergistic interactions for glycerol oxidation over Pt/TMC catalysts. [Display omitted] • Pt-modified transition metal carbides (TMCs) were compared with Pt/C for complete glycerol electrooxidation. • In-situ FTIR revealed Pt/TMC enhanced CO 2 selectivity and lowered onset potential. • Synergy between Pt and TMCs enhanced glycerol binding energy and reduced CO binding energy. [ABSTRACT FROM AUTHOR]

• Ultrathin cobalt carbide (Co 2 C) nanosheets are firstly employed as photothermal catalysts. • Efficient degradation of mustard-gas simulants (CEES) is realized under solar light. • Catalytic performance of Co 2 C is better than nanocrystalline TiO 2 under identical conditions. • Mechanism of photothermal-driven CEES degradation on Co 2 C is clearly revealed. Here, ultrathin cobalt carbide (Co 2 C) nanosheets are firstly illustrated as effective and robust catalysts toward photothermal degradation of sulfur mustard simulants (e.g., 2-chloroethyl ethyl sulfide, CEES) under solar light. Under the optimal conditions, the degradation rate of CEES by Co 2 C nanosheets is up to 98 %, which is much higher than the widely used P25 and anatase TiO 2 nanoparticles. Moreover, the degradation performance is comparable or even better than those typical photothermal catalysts, including MnO 2 , MnO x -TiO 2 and Co 3 O 4 , under identical conditions. Experimental evidences and density functional theory (DFT) calculations reveal that the superior activity is attributed to three main reasons: (i) the high photo-to-heat conversion efficiency of Co 2 C enables an elevated surface temperature for chemical bond breaking, (ii) the feasible binding of CEES on Co 2 C surface via Co S and Co Cl coordination promotes the process of degradation, and (iii) the surface hydroxyl groups (OH) on Co 2 C nanosheets favor the degradation of CEES. Obviously, this work provides new insights into practical and large-scale application of transition metal carbides (TMCs) as novel photothermal catalysts in the decontamination of chemical warfare agents (CWAs) under ambient conditions (i.e., solar light and room temperature). [ABSTRACT FROM AUTHOR]

• MXenes show great potential for catalyzing industrially relevant processes. • MXenes (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo; W; X = C; N) exothermically adsorb water. • Activation energies for the first O H bond cleavage in H 2 O are below 0.44 eV. • MXenes dissociate water more effectively than surfaces containing noble metals. Two-dimensional few-layered transition-metal nitrides and carbides, called MXenes, have attracted a great interest given their large surface areas and their unique physicochemical properties. Motivated by the known reactivity of surfaces of bulk transition metal carbides on the mechanism behind the water-gas shift (WGS) reaction, density functional theory (DFT) calculations were employed to investigate the bonding of water and its dissociation on a set of eighteen M 2 X MXene (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, while X = C or N) surfaces. Here it is shown that all the studied MXenes exothermically adsorb water, with adsorption energies ranging from -1.43 to -2.94 eV, and greatly facilitate its dissociation, with energy barriers below 0.44 eV. These results reinforce the role of MXenes in promoting water dissociation, effectively suggesting their potential as catalysts for industrially relevant processes such as the WGS reaction. [ABSTRACT FROM AUTHOR]