Metal-Free Carbon Nitride Nanosheet Supported the Pentacoordinated Silicon Intermediates for Photocatalytic Overall Water Splitting
Anqi Shi, Dazhong Sun, Ruilin Guan, Wenchao Shan, Ziyang Qin, Juncheng Wang, Lujun Wei, Shuang Zhou, Xiuyun Zhang, Xianghong Niu
Abstract
Photocatalytic overall water splitting is a promising approach to overcome the environmental and energy crisis. However, developing effective photocatalysts with well activity, light absorption, and photogenerated carrier lifetime is still a challenge. Herein, combining extensive first-principles and nonadiabatic molecular dynamics calculations, we find that microporous carbon-nitride nanosheets with a pyridinic nitrogen, such as C 2 N and C 6 N 6, possess the pentacoordinated silicon intermediates’ bonding environment. The pentacoordinated silicon as intermediates exhibits good photocatalytic performance for the difficult four-electronic oxygen evolution reaction. The overpotential is only 0.55 V for C 2 N, which is significantly lower than that of the tetracoordinated silicon intermediates (2.00 V). Simultaneously, the decoration of the silicon group not only widens the absorption range of visible light but also maintains the lifetime of photogenerated carriers on the nanosecond scale, which enhances the application efficiency of solar energy. Our work paves a new route for advancing photocatalytic overall water splitting.