The regulating effect of twisted angle on the photocatalytic overall water splitting for C3N/C3B heterojunction
Xianghong Niu, Xue-Mei Zhang, Anqi Shi, Dazhong Sun, Ruilin Guan, Wenchao Shan, Fengfeng Chi, Shasha Li, Bing Wang, Xiuyun Zhang
Abstract
The construction of van der Waals heterojunctions for photocatalytic overall water splitting is a promising strategy for obtaining clean energy. Good carrier separation, broadened photo-absorption, and efficient catalytic activity are crucial factors remaining significantly challenging. Herein, based on first-principles calculations, taking C3N/C3B as an example, we demonstrate that the suitable twisted angle (θ) formed in the layered structure is an efficient strategy to regulate photocatalytic properties of two-dimensional materials. For the heterojunctions stacked with θ = 19.1° and 40.9°, the layer-to-layer interaction introduced by the moiré pattern provides an electrostatic potential difference of up to 2.1 eV, about 0.8 eV higher than non-twisted. The enhanced built-in electric field not only alleviates the redox potential limit of water splitting but also promotes the transfer of photogenerated carriers. Meanwhile, the twisted C3N/C3B improves the visible light response by opening the transition channels in the low-energy region. Especially for the difficult four-electron oxygen evolution reaction, the overpotential is reduced from 0.70 to 0.52 V based on the moiré potential, which can be easily conquered for the twisted C3N/C3B with sufficient redox potential. Interlayer torsion provides an effective regulation strategy to improve the photocatalytic overall water splitting performance for metal-free heterojunctions.