GaN-Mediated Synergy with Iridium Species for Light-Driven Neat Formic Acid Dehydrogenation

Light-driven formic acid (FA) dehydrogenation for on-site H2 production provides an innovative strategy for addressing the issues of H2 storage and transportation. Herein, by assembling gallium nitride (GaN) nanowires with dispersed IrO2 nanoclusters, a nanohybrid photocatalyst with strong interaction was developed for efficient and durable light-driven H2 production from neat FA without any solvents and/or additives. As revealed by in situ spectroscopic characterizations and computational investigations, the GaN nanowire-mediated interaction with IrO2 nanoclusters facilitates efficient separation and directional transfer of charge carriers and endows the photocatalyst with antisintering capability. Moreover, the synergistic effect between GaN and IrO2 selectively breaks the O–H and C–H bonds of FA in sequence via a formate reaction pathway with a greatly reduced activation energy. Benefiting from these distinct properties, the photocatalyst delivers a H2 evolution rate of 220.5 mol·gcat.–1·h–1 with a marked selectivity of 99% and a turnover frequency of 8.1 × 105 per hour under focused light illumination without external thermal input. A record-high total turnover number of 1.3 × 108 is achieved over an operation of 700 h. This work provides a strategy for mediating catalytic sites by GaN for light-driven FA dehydrogenation.