Efficient Nb2O5@g-C3N4 heterostructures for enhanced photocatalytic CO2 reduction with highly selective conversion to CH4

Abstract

Achieving the goal of carbon neutralization using photocatalytic CO₂ reduction has garnered widespread attention. However, rapid photogenerated charge recombination seriously impedes the further improvement of photocatalytic properties. In response, we propose a strategy to solve this limitation by way of constructing a heterojunction. A Nb₂O₅@g-C₃N₄ type II heterojunction photocatalyst was developed by a straightforward hydrothermal method. The construction of a heterojunction greatly accelerates the separation of photoinduced charges and increases the photocatalytic activity. As a result, Nb₂O₅@g-C₃N₄ (1 : 5) possesses outstanding properties for CO₂ reduction under visible light with the production of CH₄ and CO of about 19.06 and 1.93 μmol g⁻¹, respectively. The CH₄ selectivity is up to 98.79%. Furthermore, the mechanism of photocatalytic CO₂ reduction is revealed in detail based on in situ DRIFTS and photochemical characterization, thus providing guidance for the design of high-performance CO₂ photoreduction systems.