A Near‐Perfect Pt Cocatalyst with a Spatially Oriented Distribution of Pt <sup>2+</sup> /Pt <sup>0</sup> for Photocatalytic Water Splitting
Sibi Liu, Youzi Zhang, Maohuai Wang, Yanping Wei, Y. Wang, Weizhe Chen, Siman Mao, Peng Guo, Jahan B. Ghasemi, Junchao Zhou, Shujie Zhang, Xuanhua Li
Abstract
Abstract Loading the cocatalyst, e.g., Pt, is a promising strategy for photocatalytic overall water splitting, in which metallic state Pt° facilitates proton reduction and positive valence state Pt 2+ inhibits H 2 /O 2 recombination. However, simultaneously leveraging the advantages of Pt 0 and Pt 2+ in Pt‐photocatalyst hybrids for photocatalytic water splitting is challenging. Herein, a universal strategy is demonstrated for modulating Pt valence state, obtaining a spatially oriented distribution of Pt 2+ /Pt 3 and a close to zero proton reduction barrier, along with isolated O 2 adsorption. As a proof of concept, Pt undergoes electron transfer to ZnIn 2 S 4 , accompanied by partial oxidation from Pt 0 to Pt 2+ through the introduction of electron‐deficient centers in ZnIn 2 S 4 via vanadium doping and sulfur vacancy (V‐Sv‐ZIS). Reverse electron transfer induces Pt 2+ dominating 83% of the region near the Pt/V‐Sv‐ZIS interface and Pt 0 dominating in the remaining 17% near the Pt cluster center, which can be extended to other Pt‐based catalyst systems. The dominant Pt 2+ inhibits O 2 adsorption and induces the lowest H 2 /O 2 recombination rate of 4%, and the minimal Pt 0 obtains a 152.2‐fold increase in photogenerated electron density, ultimately realizing a 45.4‐fold increase in photocatalytic activity. A 10 m 2 large‐area photocatalytic system is fabricated, producing 6.4 L of H 2 per day under natural sunlight.