Hydroxyl-Bonded Co Single Atom Site on Boroncarbonitride Surface Realizes Nonsacrificial H₂O₂ Synthesis in the Near-Infrared Region.

Abstract

Photocatalytic synthesis of hydrogen peroxide (H₂O₂) from O₂ and H₂O under near-infrared light is a sustainable renewable energy production strategy, but challenging reaction. The bottleneck of this reaction lies in the regulation of O₂ reduction path by photocatalyst. Herein, the center of the one-step two-electron reduction (OSR) pathway of O₂ for H₂O₂ evolution via the formation of the hydroxyl-bonded Co single-atom sites on boroncarbonitride surface (BCN-OH₂/Co₁) is constructed. The experimental and theoretical prediction results confirm that the hydroxyl group on the surface and the electronic band structure of BCN-OH₂/Co₁ are the key factor in regulating the O₂ reduction pathway. In addition, the hydroxyl-bonded Co single-atom sites can further enrich O₂ molecules with more electrons, which can avoid the one-electron reduction of O₂ to •O₂ ^-, thus promoting the direct two-electron activation hydrogenation of O₂. Consequently, BCN-OH₂/Co₁ exhibits a high H₂O₂ evolution apparent quantum efficiency of 0.8% at 850 nm, better than most of the previously reported photocatalysts. This study reveals an important reaction pathway for the generation of H₂O₂, emphasizing that precise control of the active site structure of the photocatalyst is essential for achieving efficient conversion of solar-to-chemical.