Construction of an arsenene/g-C3N4 hybrid heterostructure towards enhancing photocatalytic activity of overall water splitting: a first-principles study

Abstract Using optical energy to split water on heterostructured photocatalysts is one of the most promising methods to solve current environmental problems. And the key challenge to achieve this goal is to get an excellent water splitting photocatalyst. Herein, the structure, electronic structure, optical performance and thermodynamic feasibility of arsenene/g-C3N4 catalyst for water splitting is investigated. It is showing that arsenene/g-C3N4 heterostructure, with type-II semiconductor characteristics, possess a suitable band gap (2.03 eV), potentials at valence band maximum (VBM) and at conduction band minimum (CBM), and thus it can effectively drive overall water splitting. Meanwhile, the arsenene/g-C3N4 heterostructure possess an exellent property to absorb visible light, and the solar-to-hydrogen (STH) efficiency reaches 17.08%. Furthermore, the free energy of the water splitting reaction is downhill in a certain pH range (3.78 - 6.49), indicating that overall water splitting can happen spontaneously. Therefore, the arsenene/g-C3N4 heterostructure is a promising candidate for photocatalytic overall water splitting.