In Situ Etching–Hydrolysis Strategy To Construct an In-Plane ZnIn2S4/In(OH)3 Heterojunction with Enhanced CO2 Photoreduction Performance

The in-plane heterojunctions with atomic-level thickness and chemical-bond-connected tight interfaces possess high carrier separation efficiency and fully exposed surface active sites, thus exhibiting exceptional photocatalytic performance. However, the construction of in-plane heterojunctions remains a significant challenge. Herein, we prepared an in-plane ZnIn 2 S 4 /In(OH) 3 heterojunction (ZISOH) by partial conversion of ZnIn 2 S 4 to In(OH) 3 through the addition of H 2 O 2 . This in situ oxidation etching–hydrolysis approach enables the ZISOH heterojunction to not only preserve the original nanosheet morphology of ZnIn 2 S 4 but also form an intimate interface. Moreover, generated In(OH) 3 serves as an electron-accepting platform and also promotes the adsorption of CO 2 . As a result, the heterojunction exhibits a remarkably enhanced performance for photocatalytic CO 2 reduction. The production rate and selectivity of CO reach 1760 μmol g –1 h –1 and 78%, respectively, significantly higher than those of ZnIn 2 S 4 (842 μmol g –1 h –1 and 65%). This work puts forward a feasible and facile approach to construct in-plane heterojunctions to enhance the photocatalytic performance of two-dimensional metal sulfides.