The strong interfacial coupling effect of Nafion between LaFeO3/electrolyte for efficient photoelectrochemical water reduction.

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.