A promising p-type Co-ZnFe2O4 nanorods film as photocathode for photoelectrochemical water splitting

The p-type Co-ZnFe2O4 film with one-dimensional (1D) rod-like morphology is firstly fabricated on Fluorine-doped tin oxide (FTO) through hydrothermal reaction and sintering treatment. The p-type Co-ZnFe2O4 is obtained by doping Co ions into n-type ZnFe2O4 which Zn sites are substituted by Co. Compared with the n-type ZnFe2O4, the light absorption edge of Co-ZnFe2O4 is obviously shifted from 589 nm to 624 nm, the positions of valence/conduction band of Co-ZnFe2O4 meet the thermodynamic requirement for water splitting. The photocurrent density of p-type Co-ZnFe2O4 is -0.22 mA∙cm-2 at 0 V vs. RHE which is enhanced 7.33 times than that of n-type ZnFe2O4 (-0.03 mA∙cm-2 at 0 V vs. RHE). This work provides useful insights for tuning p-n character of semiconductors for realizing efficient PEC water splitting.