Photoelectrochemical activity of Cu2O electrochemically deposited at different temperatures

Abstract

Listen

Translate article

Cuprous oxide (Cu2O) is considered one of the most promising candidates for photocathodes in photoelectrochemical systems due to its favorable properties including p-type conductivity and narrow band gap. Therefore, Cu2O thin films were electrochemically deposited on FTO-coated glass from the bath containing 0.2 M CuSO4 and 3 M lactic acid (pH=12) at the potential of −0.5 V vs SCE for 1 h at three different temperatures (20 °C, 40 °C, and 60 °C). The obtained materials were characterized using various techniques including SEM/EDS, XRD, UV–vis DRS, and EIS measurements. It was found that rising the electrodeposition temperature causes not only an increase in the oxide growth rate but also influences the crystallite orientation preference (the higher preferred orientation of the 〈111〉 plane was observed at higher temperatures). Photoelectrochemical measurements confirmed the superior performance of the FTO/Cu2O cathode synthesized at the highest studied temperature (60 °C), most likely due to the greater thickness of the deposit as well as higher material texture. On the contrary, the optical and electrochemical band gaps were found to be independent of the temperature applied during deposition. Finally, the possibility of using such kind of electrochemically synthesized FTO/Cu2O photocathodes for solar light-induced ammonia synthesis was also demonstrated.