Solar-active titanium-based oxide photocatalysts loaded on TiN array absorbers for enhanced broadband photocurrent generation

Abstract

Efficient utilization of a wide range of the solar spectrum in photoelectrochemical conversion is one of the primary requirements for photocatalyst materials. Here, we report an effective approach to combine solar-absorptive titanate-based oxide photocatalysts with titanium nitride (TiN) to demonstrate the enhanced photocurrent generation extending from the ultraviolet to the near-infrared region. Pseudobrookite Fe2TiO5 and Cr-doped TiO2 are, respectively, loaded on the TiN nanodisk arrays to demonstrate the photocurrent generation in opposite directions. By incorporating the TiN nanodisk arrays, the photocatalytic performance of Fe2TiO5 has increased by 26-fold in the UV region and ∼11-fold in the visible region due to the strong UV–visible light absorption, hot electron generation at the TiN nanodisk array, and their subsequent injection into the oxide. Similarly, the photocatalytic performance of Cr-TiO2 has increased by ∼18-fold in the UV region and ∼sixfold in the visible region by the hot hole transfer from TiN. This work demonstrates the effective utilization of titanium-based catalysts activated with both hot-electrons and holes from the TiN, yielding the visible-photocurrent generation and thus the improved photon management in solar photocatalysis.