Ultrasmall NiFe-Phosphate Nanoparticles Incorporated α-Fe2O3 Nanoarrays Photoanode Realizing High Efficient Solar Water Splitting

The practical application of hematite (alpha-Fe2O3) in solar water splitting is severely limited by the highly charge recombination rate though its abundant reserves and suitable bandgap of similar to 2.1 eV. This work describes the synthesis of ultrasmall NiFe-phosphate (NFP) nanoparticles incorporated alpha-Fe2O3 nanoarrays photoanode via a facile dip-coating and annealing process to demonstrate combined effects on enhanced photoelectrochemical (PEC) water oxidation. The NFP uniformly decorating on the surface of hematite nanorods not only could improve water oxidation kinetics and charge separation efficiency, but also could suppress the charge recombination in company with the surface states passivation. Furthermore, the phosphate (P) in the NFP nanoparticles could also play a synergistic effect on promoting the multiproton-coupled electron transfer (PCET) process for the PEC water oxidation. All of these lead to similar to 140 mV cathodic shift of onset potential, similar to 2.3-fold enhancement of the photocurrent and excellent long-term stability at 1.23 V-RHE in 0.1 M KOH solution for alpha-Fe2O3/NFP photoanode. Along with these advantages, the NFP nanoparticles may possess new opportunities for modulating PEC water oxidation performances in hematite and other metal oxide photoanodes.