Finding a highly efficient, selective and economic approach for electrochemical reduction of aqueous carbon dioxide is a great challenge in realizing an artificial system for a sustainable carbon cycle. Novel mesoporous palladium–copper bimetallic electrocatalysts with superior activity and high faradaic efficiencies (FEs) are reported for the first time. The mesoporous nanostructure provides a roughened surface which is abundant in active sites and promotes selective conversion of CO₂ to CO. First-principles calculations exhibit that Pd atoms on the catalyst surface serve as reactive centers and highly selective CO formation is attributed to the geometric and electronic effects within the palladium–copper bimetallic alloys. The CO₂ and COOH* intermediate adsorption ability and the CO desorption ability on Pd atoms are effectively enhanced in the presence of Cu. Our results provide wide ranging implications for further improving the design and preparation of CO₂ reduction electrocatalysts.

The effects of interlayer lone-pair interactions on the electronic structure of SnO are explored using density-functional theory.

SrTiO₃ is a promising photocatalyst for the production of hydrogen from water splitting under solar light. Cr doping is an effective treatment for adjusting its absorption edge to the visible-light range, although the performance of Cr-doped SrTiO₃ is strongly affected by the oxidation number of the Cr ions. In this study, we theoretically predict that elevating the Fermi level, i.e., n-type carrier doping in SrTiO₃, can stabilize the desirable oxidation number of chromium (Cr³⁺), contributing to a higher activity for H₂ evolution. Our computational results, based on hybrid density-functional calculations, reveal that such an n-type condition is realized by substituting group-V metals (Ta, Sb, and Nb), group-III metals (La and Y), and fluorine atoms for the Ti, Sr, and O sites in SrTiO₃, respectively. From our systematic study of the capability of each dopant, we conclude that La is the most effective donor for stabilizing Cr³⁺. This prediction is successfully evidenced by experiments showing that the La and Cr codoped SrTiO₃ dramatically increases the amount of H₂ gas evolved from water under visible-light irradiation, which demonstrates that our guiding principle based on Fermi level tuning by the codoping scheme is valid for the design of advanced photocatalysts.