Light-Induced Activation of Adaptive Junction for Efficient Solar-Driven Oxygen Evolution: In Situ Unraveling the Interfacial Metal–Silicon Junction

The integration of surface metal catalysts with semiconductor absorbers to produce photocatalytic devices is an attractive method for achieving high-efficiency solar-induced water splitting. However, once combined with a photoanode, detailed discussions of the light-induced processes on metal/semiconductor junction remain largely inadequate. Here, by employing in situ X-ray scattering/diffraction and absorption spectroscopy, the generation of a photoinduced adaptive structure is discovered at the interfacial metal–semiconductor (M–S) junction between a state-of-the-art porous silicon wire and nickel electrocatalyst, where oxygen evolution occurs under illumination. The adaptive layer in M–S junction through the light-induced activation can enhance the voltage by 247 mV (to reach a photocurrent density of 10 mA cm−2) with regard to the fresh photoanode, and increase the photocurrent density by six times at the potential of 1.23 V versus reversible reference electrode (RHE). This photoinduced adaptive layer offers a new perspective regarding the catalytic behavior of catalysts, especially for the photocatalytic water splitting of the system, and acting as a key aspect in the development of highly efficient photoelectrodes. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim