Enhanced Photoelectrochemical Performance of Hematite Photoanode by Decorating NiCoP Nanoparticles Through a Facile Spin Coating Method

Abstract Hematite (α-Fe 2 O 3 ) is a potential photoanode material for photoelectrochemical (PEC) water splitting, but its short hole diffusion length and low water oxidation kinetics prevent its practical application. In general, the hole transport rate and the water oxidation kinetics could be improved by modifying the oxygen evolution cocatalysts (OECs) in the proper way. In this work, we designed and synthesized a bimetallic phosphides NiCoP nanoparticles (NPs) modified (Ti, Zr)-codoped hematite photoanode (TZ-H) by a facile spin coating method to achieve the uniform and close interface contact of semiconductor/OECs. Under the optimal conditions, the as-prepared photoanode exhibits high and stable PEC performance with a current density of 2.38 mA/cm 2 at 1.23 V vs. RHE, which is one of the best performances of noble-metal-free hematite-based photoanodes for water oxidation. Moreover, the surface efficiency of charge separation is improved by NiCoP modification, which is increased from 59% to 91% at 1.23 V vs. RHE and reached nearly 99% at higher potential. This work not only proves that NiCoP NPs are outstanding OECs but also provides a new strategy for the design of noble-metal-free semiconductor/OECs photoanodes with high-quality interface contact. Graphic Abstract