Photoelectrochemical oxygen evolution improved by a thin Al2O3 interlayer in a NiOx/n-Si photoanode

Abstract We employ a thin Al 2 O 3 interlayer between p-NiO X catalyst/n-Si photoanode interfaces to realize an effective oxygen evolution reaction (OER). The Al 2 O 3 interlayer is used to reduce the interface defect density, enhance the band bending by suppressing the Fermi-level pinning effect, and enhance photovoltage at the catalyst/semiconductor rectifying junction. Our NiO X /Al 2 O 3 /n-Si photoanodes generated a photocurrent of 3.36 mA/cm 2 at the equilibrium potential of OER (E OER = 1.23 V vs. reversible hydrogen electrode in 1 M NaOH solution) and a solar-to-oxygen conversion efficiency of 0.321%. Moreover, the photoanode showed no sign of decay over 20 h of photoelectrochemical water oxidation.