Ice-Templated Synthesis of Atomic Cluster Cocatalyst with Regulable Coordination Number for Enhanced Photocatalytic Hydrogen Evolution

Supported metal catalysts have been exploited in various applications. Among them, cocatalyst supported on photocatalyst is essential for activation of photocatalysis. However, cocatalyst decoration in a controllable fashion to promote intrinsic activity remains challenging. Herein, a versatile method is developed for cocatalyst synthesis using an ice-templating (ICT) strategy, resulting in size control from single-atom (SA), and atomic clusters (AC) to nanoparticles (NP). Importantly, the coordination numbers (CN) of decorated AC cocatalysts are highly controllable, and this ICT method applies to various metals and photocatalytic substrates. Taking narrow-band gap Ga-doped La5Ti2Cu0.9Ag0.1O7S5 (LTCA) photocatalyst as an example, supported Ru AC/LTCA catalysts with regulable Ru CNs have been prepared, delivering significantly enhanced activities compared to Ru SA and Ru NPs supported on LTCA. Specifically, Ru(CN = 3.4) AC/LTCA with an average CN of RuRu bond measured to be approximate to 3.4 exhibits excellent photocatalytic H2 evolution rate (578 mu mol h-1) under visible light irradiation. Density functional theory calculation reveals that the modeled Ru(CN = 3) atomic cluster cocatalyst possesses favorable electronic properties and available active sites for the H2 evolution reaction. A versatile ice-templating method is developed to synthesize photocatalyst cocatalysts with controllable coordination numbers, and morphologies ranging from single atoms to atomic clusters and nanoparticles. The approach is effective for various metals and photocatalysts. Ru atomic clusters with controlled coordination number loaded on Ga-doped La5Ti2Cu0.9Ag0.1O7S5 enhance photocatalytic H2 evolution. This atomically controllable cocatalyst strategy is significant for boosting photocatalysis. image