Construction of porous Ni2P cocatalyst and its promotion effect on photocatalytic H2 production reaction and CO2 reduction

Due to superior light absorption abilities, porous materials are suitable to be served in photocatalytic reactions. In this study, porous Ni2P is target-constructed from porous Ni(OH)2 nanoflower. Promotion effect of the porous Ni2P as cocatalyst is confirmed on photocatalytic performance of Ni2P/CdS composite. The constructed porous Ni2P/CdS photocatalyst shows much higher photocatalytic H2 evolution rate (111.3 mmol h-1 g-1) from water and much higher CO (178.0 mmol h-1 g-1) and CH4 (61.2 mmol h-1 g-1) evolution rates from CO2 reduction than non-porous Ni2P/CdS photocatalyst. Characterizations including UV-Vis diffuse reflectance, photoluminescence, transient photocurrent response, electrochemical impedance and electron paramagnetic resonance are conducted to verify the role of porous Ni2P cocatalyst. The slow photon effect derived from porous structure Ni2P is found to improve light path and increase the absorption utilization of light. The enhanced photocurrent intensity and the lowered resistance of porous Ni2P/CdS due to the formed heterojunctions indicate much rapid isolation of photogenerated electron-hole pairs and rapid charge transfer of electrons. The higher signal of ,O2- radicals is detec-ted in porous Ni2P/CdS than non-porous Ni2P/CdS, which result in the remarkable photocatalyst activities of porous Ni2P/CdS. Reaction mechanisms over Ni2P/CdS photo -catalyst are illustrated with a Z-scheme charge transfer path.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.