Triadic Layered Double Hydroxide Modified Semiconductor Heterojunction for PEC Water Splitting

Efficient charge separation and rapid surface reaction kinetics play a significant part in the efficiency of solar water splitting. A novel triadic MoO3/BiVO4/CoMnZn photoanode was prepared successfully via metal organic decomposition and electrodeposition methods. Compared with the original BiVO4 photoanode, the as-prepared novel photoanode significantly broadens the visible light absorption and increases the photocurrent density up to 1.24 mA/cm2 at 1.23 versus RHE that is 2.21 and 1.51 times those of pure BiVO4 and MoO3/BiVO4 photoanodes. The incident photon-to-current efficiency value of the ternary photoanode is 1.83 times that of the pure BiVO4 at λ = 420 nm. The reason for the enhancement is recognized to be the formation of MoO3/BiVO4 heterojunction that inhibits the recombination of electron and hole pair, while the existence of CoMnZn cocatalyst effectively reduces carrier recombination at photoanode/electrolyte interfaces, which in turn further improves the photocurrent density and has been verified by the calculated carrier density, carrier transport resistance, and carrier life from the mass, electrochemical impedance, and intensity modulated photocurrent spectra.