Surface vulcanization activates α-Fe2O3/NiCo-LDH photoelectrode surface activity leading to high photoelectrochemical performance

Abstract

Effective carrier separation and good electrochemistry are important for the realization of efficient photoelectrocatalysis. Firstly, NiCo-LDH hydrotalcite nanosheets were integrated into an α-Fe₂O₃ photoanode by a hydrothermal method, and the α-Fe₂O₃/NiCo-LDH surface was further treated by surface vulcanization. Compared with the original α-Fe₂O₃ photoelectrode, the photoelectrochemical (PEC) performance of α-Fe₂O₃/NiCo-S after surface vulcanization has been significantly improved, its photocurrent density has reached 0.71 mA cm⁻² at 1.23 V, and its stability has also been significantly improved. On the one hand, the improvement of PEC performance of the photoelectrode can be attributed to the reduction of surface defects due to surface vulcanization, which reduces the charge transfer resistance and increases the carrier density to promote further charge transfer; on the other hand, surface vulcanization further improves the surface active sites of the photoanode and promotes the rapid transfer of holes, thus enhancing the rapid separation and transfer of charges. In this paper, α-Fe₂O₃ was modified by loading the NiCo-LDH cocatalyst and surface vulcanization, and the carrier recombination inside the photoelectrode and the water oxidation kinetics on its surface were improved at the same time. This modification strategy is expected to improve the intrinsic photochemical activity of other semiconductor photoelectrodes, facilitating their further application in solar energy conversion.