Constructing FeCoNi-LDH/MOF heterostructures as cocatalysts on hematite photoanodes for high efficiency water splitting

Insufficient surface dynamics and severe carrier recombination limit the photoelectrochemical water splitting (PEC-WS) performance of hematite (alpha-Fe2O3) photoanodes. The surface/interface engineering as an effective method can improve the above-mentioned problems. In this study, the ZIF-67 and FeCoNi-LDH as cocatalysts formed via in situ hydrolysis are successfully introduced on the surface of the alpha-Fe2O3 photoanode to improve the photogenerated carrier transport. The Sn@alpha-Fe2O3/ZIF-67/FeCoNi-LDH photoanode exhibits an excellent photocurrent density of 1.72 mA cm-2 at 1.23 VRHE, which is 1.7 times that of the original alpha-Fe2O3 photoanode. The detailed studies demonstrate that the introduced ZIF-67/FeCoNi-LDH heterojunction cocatalyst provides more abundant surface active sites and defects and enhances the light absorbance ability and electric conductivity. The synergistic effect between ZIF-67 and FeCoNi-LDH cocatalysts can significantly enhance photogenerated carrier separation and transfer efficiency.