The strong interfacial coupling effect of Nafion between LaFeO3/electrolyte for efficient photoelectrochemical water reduction
Abstract Insufficient reduction capability and scanty active substance limit the application of LaFeO3 (LFO) in the field of photoelectrochemical (PEC) water splitting. In this work, a judicious combination of LFO/Nafion composite to improve the PEC performance by a special dip-coating method on the FTO is demonstrated. The photocurrent density of the LFO electrode coated with two layers Nafion increased to -23.9 μA/cm2 at 0.47 V vs RHE, which is 4.1 times that of the pristine LFO. Based on the experimental data and theoretical analysis,the improvement of the PECproperties is attributed to the construction of organic/inorganic units, which would enable strong electronic coupling and favor interfacial charge transfer, resulting in a 30mV downward shift of its flat band potential. Thus, conduction band gets closer to the proton reduction potential of H+ to H2 after decoration with Nafion, resulting in stronger photogenerated electron reduction ability. Our study provides insights that organic materials modify semiconductor photoelectrodes for accelerating the charge kinetics.