The electrochemical carbon dioxide reduction reaction to syngas with controlled CO/H 2 ratios has been studied on Pd-based bimetallic hydrides using a combination of in situ characterization and density functional theory calculations. When compared with pure Pd hydride, the bimetallic Pd hydride formation occurs at more negative potentials for Pd-Ag, Pd-Cu, and Pd-Ni. Theoretical calculations show that the choice of the second metal has a more significant effect on the adsorption strength of *H than *HOCO, with the free energies between these two key intermediates (i.e., ΔG(*H)–ΔG(*HOCO)) correlating well with the carbon dioxide reduction reaction activity and selectivity observed in the experiments, and thus can be used as a descriptor to search for other bimetallic catalysts. The results also demonstrate the possibility of alloying Pd with non-precious transition metals to promote the electrochemical conversion of CO 2 to syngas.

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In this study, the experimentally measured hydrogen evolution reaction exchange current densities for metal monolayer-modified transition metal carbides (TMCs) are correlated with density functional theory calculations of adsorbed hydrogen and hydroxyl binding energies. The correlation reveals a volcano relationship in alkaline electrolytes, while the hydroxyl binding energy does not appear to show a strong correlation. These results should provide guidance for further improving the electrocatalytic activity of metal-modified TMCs in an alkaline environment.

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Understanding water dissociation on nonprecious metal surfaces is essential toward designing efficient catalysts for important chemical reactions such as water-splitting and carbon dioxide reduction. Hydrogen binding energy (HBE) has been proposed to be a good descriptor to predict hydrogen evolution reaction (HER) activity in alkaline electrolytes. In this work, we showed that although HBE values could predict the HER activity reasonably well, the oxophilicity of the catalyst surface also played a significant role in water dissociation. To elucidate the role of surface oxophilicity, a series of nonprecious copper-based bimetallic materials were systematically studied for HER activity in alkaline conditions. By alloying copper with small amounts of oxophilic transition metals such as Ti, Co, or Ni, a significant enhancement in HER activity was achieved in comparison to pure copper. However, if the HBE was considered as the sole descriptor, the experimentally measured HER activity trend did not match the theoretical trend as predicted by density functional theory (DFT) calculations. Further studies combining both computational efforts and experimental investigation of metal oxide/hydroxide (MO/OH) clusters deposited on Cu surfaces showed that oxygen binding energies (i.e., the oxophilicity of the dopant metal) together with HBEs should be used as descriptors to predict HER activity in alkaline conditions due to the synergistic interactions between copper and the oxophilic metal.

The surface properties that determine the selectivity of Mo 2 C catalysts in ethane oxidative dehydrogenation with CO 2 as a soft oxidant were investigated using a combination of pulse experiments and in-situ spectroscopic methods. Oxygen modification was discovered to be crucial for inhibiting the cleavage of the C−C bond in ethane and enhancing the production of ethylene. The addition of the Fe promoter accelerated the formation of surface oxygen species and stabilized them from reduction by ethane, leading to a shorter induction period, higher ethylene yield, and improved stability.

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