Rational design and fabrication of Cu2O film as photoelectrode for water splitting

Cu2O can be n-type and p-type depending on the oxygen and copper vacancies as either photocathode or photoanode for water splitting. However, the synthesis of n-type Cu2O is still a challenge. At the condition of pH= 6 and ΔU= −0.05 V, n-type Cu2O films can be electrodeposited at varied temperatures. The bandgap of n-type Cu2O films is in the range of 1.6–2.0 eV with the impurity level of 1.57 eV. Among them, n-type Cu2O films deposited at 60 °C achieved the highest photocurrent in water splitting (pH=7) as the light on due to the less impurity concentration and more highly texture structure. The n-type Cu2O photoelectrode shows a stable LSV cycling performance in Na2SO4 solution as compared to the buffer acetate and phosphate solution which may be due to the formation of Cu(OH)2 layer. This work can benefit the electrodeposition of n-type Cu2O for future water splitting applications.