Visible-light overall water splitting on g-C3N4 decorated by subnanometer oxide clusters

Abstract

Two-dimensional (2D) nitrogenated holey carbon materials are promising non-precious photocatalysts for clean energy production. However, their efficiency is limited by the fast electron-hole recombination and lack of active sites. To overcome these drawbacks, here for the first time, we show that loading subnanometer p-block metal oxide clusters on 2D porous carbon-based semiconductors can trigger peculiar synergistic effect and offer an effective route for manipulating the photocatalytic behavior at atomic precision. As a prototype system, g-C3N4 monolayer decorated by MgO tubular clusters for overall water splitting is explored by time-dependent ab initio nonadiabatic molecular dynamic simulations. Such novel (MgO)n/g-C3N4 heterostructures possess excellent stability in aqueous solution, high activity for water splitting, and superior photocarrier transport properties. The basic rules for optimally steering the relaxation pathway and lifetime of excited carriers and creating bifunctional reaction centers by controlling the concentration and size of oxide clusters are thoroughly unveiled. Our work provides a new strategy to modify 2D porous carbon materials for practical solar energy conversion and shines light on utilizing subnanometer p-block oxide clusters with earth-abundant and low-cost elements for precisely dictating the performance of hybrid photocatalysts.