Regulating the electronic structure of plasmonic Co/Cu catalysts through morphology engineering to enhance visible-light-driven hydrogen generation from aqueous ammonia borane

Abstract

Tailoring the electronic structure of the active sites for heterogeneous catalysts is vital to enhance their catalytic performance in various reactions. In this study, plasmonic Co/Cu with different morphologies, including cube, truncated octahedron, sphere, and dodecahedron, were synthesized to explore the impact of the exposed crystal facets on the electronic structure and the charge transfer in photocatalytic hydrogen generation from aqueous ammonia borane (NH₃BH₃). The results show that the Cu supports with localized surface plasmon resonance (LSPR) could capture visible light. The generated electrons from the Cu supports could be effectively transferred from Cu to Co and could then participate in the hydrogen generation reaction. Among these four Co/Cu catalysts with different morphologies, Co nanoparticles immobilized by Cu cubes with exposed (111) and (200) facets exhibited the highest photocatalytic activity with a total turnover frequency value of 176.5 min⁻¹ at room temperature, which was mainly because the intersection site between the (111) and (200) facets could promote electron transfer from Cu to Co, thus resulting in synergistic electron enrichment on the Co active sites. This study presents an important paradigm for optimizing the electronic structure and enhancing the catalytic performance.