Abstract Hierarchically nanostructured CdS composed of 4.7 nm-thick self-assembled ultrathin nanosheets was synthesised through a microwave-assisted solvothermal method. Ag2S nanoparticles (NPs) were deposited at the edge of the CdS nanosheets by an in situ ion exchange strategy. The hierarchically CdS–Ag2S nanocomposites exhibited a high visible light photocatalytic H2 evolution rate of 375.6 μmol h−1 g−1, which was 11.5 times higher than that of pure CdS. Given the difference in work functions between CdS and Ag2S, electrons diffused from the CdS side to the Ag2S side until the Fermi levels align after their contact. When the CdS–Ag2S was illuminated, the photogenerated electrons on the conduction band of the CdS further migrated to Ag2S. Considering the lower overpotential of Ag2S, the electrons more easily participated in the reduction of protons. Meanwhile, the holes on the valence band of CdS reacted with the hole sacrificial agent (triethanolamine). In this process, the photogenerated electron–hole pairs realised effective separation. The introduction of Ag2S also enhanced the utilisation of infrared light and increased the temperature of CdS surface.

中文翻译：

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用于高效光催化制氢的分级 CdS-Ag2S 纳米复合材料

摘要 通过微波辅助溶剂热法合成了由 4.7 nm 厚的自组装超薄纳米片组成的分层纳米结构 CdS。Ag2S 纳米粒子 (NPs) 通过原位离子交换策略沉积在 CdS 纳米片的边缘。分级 CdS-Ag2S 纳米复合材料表现出 375.6 μmol h-1 g-1 的高可见光光催化析氢速率，是纯 CdS 的 11.5 倍。鉴于 CdS 和 Ag2S 之间的功函数不同，电子从 CdS 一侧扩散到 Ag2S 一侧，直到它们接触后费米能级对齐​​。当照射 CdS-Ag2S 时，CdS 导带上的光生电子进一步迁移到 Ag2S。考虑到 Ag2S 的过电位较低，电子更容易参与质子的还原。同时，CdS 价带上的空穴与空穴牺牲剂（三乙醇胺）反应。在这个过程中，光生电子-空穴对实现了有效的分离。Ag2S 的引入还增强了红外光的利用并提高了 CdS 表面的温度。