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

Abstract 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.