Development of Dual-Nanoarchitecture Photoanodes Based on Microwave-Assisted ZnS(en)0.5 Nanoplates for Photoelectrochemical Hydrogen Generation

Abstract

In this study, a microwave-assisted (MW) synthesis approach is used to develop an inorganic–organic ZnS(en)0.5 nanoplate (NP) on a Zn foil substrate. Morphological studies revealed that the growth of the ZnS(en)0.5 NP on Zn foil increased with prolonged MW irradiation time. Additionally, X-ray diffraction analysis, fourier transform infrared spectroscopy, and transmission electron microscopy unveiled the structural properties of the inorganic–organic hybrid ZnS(en)0.5 NP electrode to investigate the morphological evolution and the growth mechanism. Furthermore, the fabricated inorganic–organic ZnS(en)0.5 NP was exposed to Cd2+-ion exchange at different temperatures (140, 160, and 180 °C for 6 h) to improve its light absorption and photoelectrochemical properties. The Zn1–xCdxS porous nanoplate (PNP)/ZnO nanorod (NR)160 photoanode (160 °C for 6 h) exhibited a high photocurrent density of 4.81 mA·cm–2 at 0.5 V vs RHE. The optimized photoanode also yielded a hydrogen evolution rate of 89.76 μmol·cm–2 under 3 h of solar light illumination. Thus, the formation of the Zn1–xCdxS porous structure and the growth of the ZnO NR during Cd2+-ion exchange enhanced the photocurrent density and, consequently, prolonged the recombination lifespan of the Zn1–xCdxS PNP/ZnO NR160 photoanode.