shows the PEC performance of the different protected photocathodes synthesized at different sulfurization conditions. It is evident that the 300°C sulfurized Sb2S3 has a later onset potential, a higher dark current and a lower photocurrent density than the 270°C and 240°C sulfurized Sb2S3. At more negative bias (-0.4 V vs RHE), photocurrent densities of around 8 mA cm -2 were obtained for the 240 °C sulfurized Sb2S3 photocathode. However, the photovoltage obtained was low (~0.1 V, as estimated from the onset potential). The protected Sb2S3 photocathodes exhibited a stable hydrogen evolution under 1 sun illumination in 1 M H2SO4 for 6 hours (Figure ), and the reproducibility of the devices was confirmed (Figure ).