High-Performance Silicon Photoanode Enhanced by Gold Nanoparticles for Efficient Water Oxidation

Ni catalyst is a low-cost catalyst for oxygen evolution reaction (OER) on silicon metal–insulator–semiconductor photoanode. We found that Au nanoparticles incorporated with Ni nanoparticles can enhance the OER activity and stability of Ni nanoparticles due to the local surface plasmon resonance (LSPR) effect of the Au nanoparticles. The efficiency of NiAu/TiO<sub>2</sub>/n-Si photoanode can be boosted at least three times under the illumination (100 mW/cm<sup>2</sup>) by LSPR effect of the Au nanoparticles. A small onset potential of 1.03 V versus reversible hydrogen electrode (overpotential, η<sub>0</sub> = −0.20 V) and a current density of 18.80 mA/cm<sup>2</sup> at 1.23 V versus reversible hydrogen electrode can be obtained. The NiAu/TiO<sub>2</sub>/n-Si photoanode exhibits a high saturation current density of 35 mA/cm<sup>2</sup>, which is greater than that of most of the state-of-the-art silicon photoanodes.