Double-atom catalysts for energy-related electrocatalysis applications: a theoretical perspective

Abstract Due to the excellent activity, selectivity, and stability, atomically dispersed metal catalysts with well-defined structures have attracted intensive research attention. As the extension of single-atom catalyst, double-atom catalyst (DAC) featuring with the metal dimer anchored on a suitable substrate has recently emerged as a research focus for the energy-related electrocatalysis reactions. Due to the flexible dual-metal sites and the synergetic effect between the two metal atoms in DACs, there are more possibilities to adjust their geometrical configurations and electronic structures. The wide tunability of the active sites could offer more opportunities to optimize the binding strength of the reaction intermediates and thus the catalytic activity and/or selectivity of chemical reactions. Moreover, the neighboring metal sites provide a platform to perform more complex electrocatalysis reaction involving the chemical bond coupling. This review aims to summarize the recent advance in theoretical research on DACs for diverse energy-related electrocatalytic reactions. It starts with a brief introduction to DACs. Then an overview of the main experimental synthesis strategies of DACs is provided. Emphatically, the catalytic performance together with the underlying mechanism of the different electrocatalytic reactions, including nitrogen reduction reaction, carbon dioxide reduction reaction, oxygen reduction reaction, and oxygen and hydrogen evolution reactions, are highlighted by discussing how the outstanding attributes mentioned above affect the reaction pathway, catalytic activity, and product selectivity. Finally, the opportunities and challenges for the development of DACs are prospected to shed fresh light on the rational design of more efficient catalysts at the atomic scale in the future.