Electroless Plating NiFeP Alloy on the Surface of Silicon Photoanode for Efficient Photoelectrochemical Water Oxidation.

N-type silicon is a kind of semiconductor with narrow band gap that has been reported as an outstanding light-harvesting material for photoelectrochemical (PEC) reactions. Decorating a thin catalyst layer on the n-type silicon surface can provide a direct and effective route toward PEC water oxidation. However, most of catalyst immobilization methods for reported n-type silicon photoanodes have been based on energetically demanding, time consuming, and high-cost processes. Herein, a high-performance NiFeP alloy (NiFeP) decorated n-type micro-pyramid silicon arrays (n-Si) photoanode (NiFeP/n-Si) was prepared by a fast and low-cost electroless deposition method for light-driven water oxidation reaction. The saturated photocurrent density of NiFeP/n-Si can reach up to ∼40 mA cm-2, and a photocurrent density of 15.5 mA cm-2 can be achieved at 1.23 VRHE under light illumination (100 mW cm-2, AM1.5 filter), which is one of the most promising silicon-based photoanodes to date. The kinetics studies showed that the NiFeP on the silicon photoanodes could significantly decrease the interfacial charge recombination between the n-type silicon surface and electrolyte.