▎ 摘　　要

Mitigating photocorrosion in the light absorber material used for photoelectrochemical solar water splitting is a subject of major research. In this work, a systematic investigation is carried out on suppressing the photocorrosion in an electrodeposited Cu2O photocathode using stable protective layers. The photocathode protected with chemical vapor deposited graphene offers significant stability, till 600 s during light chopping chronoamperometry. However, the presence of a few microcracks in the graphene layer cannot offer complete protection, and causes a gradual decay in the photocurrent. The addition of an ultrathin layer (approximate to 10 nm) of amorphous TiO2 on top of the graphene blocks the microcracks, thereby resulting in complete protection to the Cu2O absorber layer. The TiO2/graphene protected Cu2O photocathode generates -3 mA cm(-2) photocurrent at 0.0 V versus reversible hydrogen electrode under 1 sun in 1 m Na2SO4 electrolyte (pH 7), which is twice that compared to the bare Cu2O electrode. The enhancement in photocurrent can be attributed to the ease of separating the photogenerated charge carriers due to the suitable band alignment and electron selective nature of the protective TiO2/graphene layers.