Enhanced photocatalytic activity and photoinduced stability of Ag-based photocatalysts: The synergistic action of amorphous-Ti(IV) and Fe(III) cocatalysts
Enhanced photocatalytic activity and photoinduced stability of Ag-based photocatalysts: The synergistic action of amorphous-Ti(IV) and Fe(III) cocatalysts
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增强银基光催化剂的光催化活性和光诱导稳定性：非晶态 Ti(IV) 和 Fe(III) 助催化剂的协同作用
DOI：
10.1016/j.apcatb.2016.01.011
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Yu Jiaguo
中科院分区：
文献类型：
--
作者：
Yu Huogen;Chen Wuying;Wang Xuefei;Xu Ying;Yu Jiaguo
近年来，银基材料因其优异的光催化性能而受到广泛关注。然而，光生电荷的快速重组和光稳定性差导致其光催化性能明显下降。本研究首次采用易浸渍法将无定形Ti（IV）作为空穴助催化剂成功负载在AgBr光催化剂表面。结果表明，当Ti（IV）助催化剂的负载量为0.05 wt%时，AgBr的光催化活性可提高1.5倍。此外，除了AgBr外，无定形Ti（IV）还可以作为有效的空穴助催化剂，大大提高其他ag基材料（如AgCl、AgI、Ag2O、Ag2CO3和Ag3PO4）的光催化性能。然而，由于Ti（IV）助催化剂快速转移光生空穴，使得更多的光生电子积聚在AgBr的导带上，由于表面晶格Ag+离子还原为金属Ag，造成了明显的失活。在这种情况下，Fe（III）作为电子助催化剂进一步表面修饰后，Ti(IV)/AgBr的光诱导稳定性和光催化活性可以得到显著提高。其原因可能是由于无定形Ti（IV）和Fe（III）共催化剂的协同作用，即Ti（IV）共催化剂作为空穴捕获中心，有效转移空穴氧化有机污染物，而Fe（III）共催化剂作为还原活性位点，有效还原氧。与昂贵的贵金属助催化剂（如Au、Pt、RuO2）相比，利用低成本的过渡金属助催化剂（如Ti、Fe）进行表面改性是开发高效光催化材料的重要方法。
In recent years, Ag-based materials have attracted a great deal of attentions due to their excellent photocatalytic performance. However, the rapid recombination of photogenerated charges and the poor photostability cause an obvious decrease of their photocatalytic performance. In this study, amorphous Ti(IV) as a hole cocatalyst was first successfully loaded on the surface of AgBr photocatalyst by a facile impregnation method. It was found that the photocatalytic activity of AgBr could be greatly improved by a factor of 1.5 when the loading amount of Ti(IV) cocatalyst was 0.05 wt%. Moreover, in addition to the AgBr, the amorphous Ti(IV) could also be used as an effective hole cocatalyst to greatly improve the photocatalytic performance of other Ag-based materials (such as AgCl, AgI, Ag2O, Ag2CO3, and Ag3PO4). However, owing to the rapid transfer of photogenerated holes by Ti(IV) cocatalyst, more photogenerated electrons were accumulated on the conduction band of AgBr, causing an obvious deactivation due to the reduction of surface lattice Ag+ions to metallic Ag. In this case, after the further surface modification by Fe(III) as an electron cocatalyst, the photoinduced stability and photocatalytic activity of Ti(IV)/AgBr could be significantly enhanced. The possible reason is due to the synergistic action of amorphous Ti(IV) and Fe(III) cocatalysts, namely, Ti(IV) cocatalyst acts as a hole-capture center to efficiently transfer holes to oxidize organic contaminants, while Fe(III) cocatalyst functions as a reduction active site to reduce oxygen efficiently. Compared with the expensive noble metal cocatalyst (such as Au, Pt, and RuO2), the surface modification by low-cost transition metal cocatalysts (such as Ti and Fe) is a significant method to develop highly efficient photocatalytic materials.