Graphdiyne (CnH2n−2) based copper(i) bromide dual S-scheme heterojunction with AX2O8 type compounds induced electron directional migration

Abstract

A fundamental strategy for enhancing the performance of photocatalytic water-splitting catalysts is to facilitate the efficient migration of photogenerated charge carriers to establish a heterojunction. In this study, we replace copper foil with CuBr as the catalytic substrate to synthesize a CuBr/graphdiyne composite that exhibits improved hydrogen evolution performance and construct a ZrMo₂O₈/CuBr/graphdiyne dual S-scheme heterojunction in conjunction with AX₂O₈-type compounds. Demonstrated via in situ XPS, charge separation in ZrMo₂O₈, graphdiyne and CuBr can be augmented by constructing dual S-scheme heterojunction to enhance the photocatalytic hydrogen evolution capability. The band structure is confirmed using ultraviolet-visible (UV-vis) spectroscopy and density functional theory (DFT) calculations. Experimental results indicate that the hydrogen evolution rate of the ZrMo₂O₈/CuBr/graphdiyne composite catalyst is five times greater than that of ZrMo₂O₈ alone, three times greater than that of CuBr, and 20 times greater than that of graphdiyne. This work investigates and expands potential synthesis methods for graphdiyne materials within photocatalysis while elucidating mechanisms promoting efficient charge separation. Furthermore, it provides novel perspectives and strategies for enhancing the hydrogen evolution efficiency of ternary photocatalysts through the development of S-scheme heterojunctions.