In situ etching-induced self-assembly of metal cluster decorated one-dimensional semiconductors for solar-powered water splitting: unraveling cooperative synergy by photoelectrochemical investigations

• Published in: Nanoscale Vol. 9; no. 43; pp. 17118 - 17132
• Main Authors: Xiao, Fang-Xing, Liu, Bin
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 01.01.2017
• Subjects: Charge transfer; Etching; Glutathione; Gold; Heterostructures; Light irradiation; Low dimensional semiconductors; Metal clusters; Nanoparticles; Nanowires; Photovoltaic cells; Self-assembly; Solar energy conversion; Surface charge; Water splitting; Zinc oxide
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/C7NR06697J

Although recent years have witnessed considerable progress in the synthesis of metal clusters, there is still a paucity of reports on photoelectrochemical (PEC) properties of metal cluster/semiconductor systems for solar energy conversion. In this work, highly ordered glutathione (GSH)-protected gold (Au) cluster (Au x @GSH) enwrapped ZnO nanowire array (NW) heterostructures (Au x /ZnO NWs) were designed by a facile, green, simple yet efficient in situ etching-induced electrostatic self-assembly strategy by modulating the intrinsic surface charge properties of building blocks, which renders negatively charged Au x clusters spontaneously and uniformly self-assembles them on positively charged ZnO NWs framework with intimate interfacial integration. It was unraveled that such Au x /ZnO NWs heterostructures demonstrated significantly enhanced PEC water splitting performance in comparison with single ZnO NWs, Au nanoparticles (Au/ZnO NWs) and GSH-capped Ag x clusters (Ag x /ZnO NWs) decorated ZnO NWs counterparts under both simulated solar and visible light irradiation. The vitally important role of Au x clusters as photosensitizer was unambiguously revealed and the merits of Au x clusters in boosting charge transfer arising from their unique core–shell architecture were highlighted by systematic comparison under identical conditions, based on which Au x cluster-mediated PEC water splitting mechanism is delineated. It is anticipated that our work can highlight the possibility of harnessing metal clusters as efficient light-harvest antennas and open new avenues for rational construction of various highly energy efficient metal cluster/semiconductor heterostructures for widespread photocatalytic and PEC applications.