B4C3 Monolayer with Impressive Electronic, Optical, and Mechanical Properties: A Potential Metal-Free Photocatalyst for CO2 Reduction under Visible Light

摘要

Visible-light-driven CO2 reduction technology offers a promising solution for the worldwide challenges of climate crisis and energy shortage. A key issue in photocatalysis is to develop environmentally benign, low-cost materials ideally with earth-abundant elements with suitable oxidizing and reducing potentials. Herein, by means of density functional theory computations and swarm-intelligence structure-searching method, we predicted the metal-free two-dimensional B4C3 monolayer as a promising green photocatalyst. Extended from a quasi-planar B4C3 cluster, the newly proposed boron carbide monolayer has not only novel tetracoordinate carbon atoms but also strong visible-light absorption, appropriate band edge alignments, and high carrier mobility, which endow the B4C3 monolayers great potential for the photocatalytic CO2 reduction. The computations of Gibbs free energy also suggest the energetic favorability in photoreduction of CO2. Remarkably, as the global minimum structure, the predicted B4C3 sheet is highly realizable in the experiment, as indicated by the impressive in-plane stiffness and weak interaction between the B4C3 and Si substrate.