Energy Platform for Directed Charge Transfer in the Cascade Z‐Scheme Heterojunction: CO2 Photoreduction without a Cocatalyst

Abstract

A universal strategy is developed to construct a cascade Z-scheme system, in which an effective energy platform is a core to direct charge transfer and separation, blocking the unexpected type-II charge transfer pathway. The dimension-matched (001)TiO 2 -g-C 3 N 4 /BiVO 4 nanosheet heterojunction (T-CN/BVNS) is the first such model. The optimized cascade Z-scheme exhibits ~19-fold photoactivity improvement for CO 2 reduction to CO in the absence of cocatalysts and costly sacrificial agents under visible-light irradiation, compared with BVNS, which is also superior to other reported Z-scheme systems even with noble metals as mediators. The experimental results and DFT calculations based on Van der Waals structural models on the ultrafast timescale reveal the introduced T as the platform could not only prolong the lifetimes of spatially separated electrons and holes but also did not compromise their reduction and oxidation potentials.