Photosensitization\nEfficiency Modulation of Atomically\nPrecise Silver Nanoclusters for Photoelectrocatalysis

Abstract

Atomically precise metal nanoclusters (NCs) have emerged\nas feasible\nalternatives to traditional photosensitizers in solar energy conversion\ndue to the unique atomic stacking mode, quantum size effect, and abundant\nactive sites. Despite the sporadic advancement in fabricating metal\nNC-based photosystems, most of which are predominantly centered on\nAu NCs, unleashing atomically precise silver nanoclusters as light-harvesting\nantennas has still been in the infant stage, with the charge transfer\nmechanism remaining elusive. Herein, we comprehensively demonstrate\nthe photosensitization effect of Ag NCs in the photoelectrochemical\n(PEC) water-splitting reaction and strictly evaluate the correlation\nof photosensitization efficiency with atomic architecture. To these\nends, tailor-made negatively charged l-glutathione (GSH)-capped\nAg NCs [Ag<i>_x</i>, Ag₉(GSH)₆, Ag₁₆(GSH)₉, Ag₃₁(GSH)₁₉] as building blocks are controllably deposited on the metal oxide\n(MOs = TiO₂, WO₃, Fe₂O₃) substrate by a facile self-assembly strategy. Benefiting from the\nhighly efficient photosensitization effect of atomically precise Ag\nNCs, these self-assembled MOs/Ag NC heterostructured photoanodes with\nan elegant charge transfer interface demonstrate significantly enhanced\nphotoelectrochemical water oxidation performances under visible-light\nirradiation on account of efficient charge transport from Ag NCs to\nthe MO substrate, substantially prolonging the charge lifetime of\nAg NCs. Our work would significantly inspire ongoing interest in unlocking\nthe generic photosensitization capability of atomically precise metal\nNCs for solar energy conversion.