Ag与Ag2O协同增强TiO2光催化制氢性能的研究

本研究采用两步法制备了电子助剂Ag和界面活性位点Ag₂O共修饰的高效TiO₂光催化剂(TiO₂/Ag-Ag₂O): 首先用光沉积法将Ag负载在TiO₂表面(TiO₂/Ag), 再经过低温煅烧法使部分Ag原位生成Ag₂O。紫外光照射TiO₂时, 激发产生的电子被助剂Ag捕获后快速传输到Ag₂O上, 电子把Ag₂O界面产氢活性位点从溶液中所捕获的氢离子还原成氢气, Ag和Ag₂O的协同作用加快了TiO₂上光生电子的转移和界面产氢反应, 从而提高了TiO₂/Ag-Ag₂O制氢性能。在300 ℃煅烧温度下制备的TiO₂/Ag-Ag₂O光催化剂制氢速率最高, 达到75.20 μmol/h, 分别是TiO₂(3.59 μmol/h)和TiO₂/Ag(41.13 μmol/h)的21.0倍和1.8倍。本研究为光催化制氢材料的设计和制备提供了有益的参考。

Synergistic Effect of Ag and Ag2O on Photocatalytic H2-evolution Performance of TiO2

Highly efficient TiO₂ photocatalysts (TiO₂/Ag-Ag₂O) co-modified by Ag as electron cocatalysts and Ag₂O as interfacial catalytic active sites were synthesized via a two-step process including the initial photoinduced deposition of metallic Ag nanoparticles on the TiO₂ surface (TiO₂/Ag) and the following in situ oxidation of partial Ag into Ag₂O by low-temperature calcination. Ag nanoparticles function as effective electron cocatalysts for the steady capture and rapid transportation of photogenerated electrons from TiO₂ surface to Ag₂O, while the adsorbed H⁺ ions from solution to Ag₂O as the interfacial catalytic active sites are reduced into H₂. The synergistic effect of Ag and Ag₂O can accelerate the electrons transfer and promote the rapid H₂-evolution reaction for enhanced photocatalytic H₂-evolution performance of TiO₂/Ag-Ag₂O. The highest H₂-evolution rate of the resultant TiO₂/Ag-Ag₂O calcinated at 300 ℃ reached 75.20 μmol/h, which was higher than those of the TiO₂ (3.59 μmol/h) and TiO₂/Ag (41.13 μmol/h) by 21.0 and 1.8 times, respectively. This study provides a new strategy for the design and synthesis of highly efficient photocatalytic H₂-evolution materials.