WO3/ZnIn2S4 heterojunction photoanodes grafting silane molecule for efficient photoelectrochemical water splitting

Designing and fabricating semiconductor photoanodes with efficient charge separation and appropriate active sites for solar energy conversion is indubitably a promising alternative to overcome the environmental crisis and energy shortage. Herein, we report a heterojunction WO3/ZnIn2S4 (WO3/ZIS) grafting silane molecule (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, AESI) as photoanode with boosted photoelectrochemical (PEC) efficiency toward highly efficient water splitting. The type II WO3/ZIS heterostructure are firstly synthesized by hydrothermal growth of WO3 nanosheets on the surface of fluorine-doped tine oxide (FTO)-coated glass, followed by depositing ZIS onto WO3 surface. After that, silane molecules are anchored on WO3/ZIS via chemical water bath method. It is demonstrated that forming WO3/ZIS heterostructure and grafting silane molecules would greatly enhance the charge separation efficiency and transfer mobility. In addition, silane molecules would offer enough reactive sites for water oxidization reaction. As a result, the obtained WO3/ZIS/AESI photoanode exhibits a photocurrent density of 1.51 mA cm(-2) under simulated solar light irradiation, to be 74.6% enhanced than that of WO3. Moreover, the incident photon-to-current conversion efficiency (IPCE) at 365 nm increases from 39.1% to 50.6% for WO3 and WO3/ZIS/AESI, respectively. The present strategy provides inspiration for preparation of photoelectrode materials in water splitting. (C) 2020 Elsevier Ltd. All rights reserved.