Dual modification of BiVO4 photoanode by rare earth element neodymium doping and further NiFe2O4 co-catalyst deposition for efficient photoelectrochemical water oxidation

BiVO4 is considered a promising semiconductor for photoelectrochemical water oxidation due to its good light absorption capacity, low cost of raw materials, and suitable band-gap. However, BiVO4 photoanode has some disadvantages, such as severe electron-hole recombination, poor kinetics of the surface reaction, and poor stability. Among known reports, this work is the first to doped Nd into the interior of BiVO4 photoanode to improve its photoelectrochemical water splitting performance. Furthermore, we chose NiFe2O4 as the oxygen evolution reaction co-catalyst to further modify the Nd-doped BiVO4 photoanode. The photocurrent density of the as-prepared NiFe2O4-Nd-BiVO4 photoanode reaches 1.93 mA cm−2, three times that of the bare BiVO4 photoanode, and the onset potential also exhibits a significant negative shift. More importantly, the stability of the NiFe2O4-Nd-BiVO4 photoanode is also significantly improved. Detailed characterization and analysis show that Nd doping induces lattice distortion, increases the charge carrier density of BiVO4, reduces impedance, and effectively suppresses electron-hole recombination. For NiFe2O4, as an oxygen evolution reaction co-catalyst, dramatically accelerates the electron-hole transfer rate kinetically and significantly improves the stability of BiVO4.