Improved H-2-generation performance of Pt/CdS photocatalyst by a dual-function TiO2 mediator for effective electron transfer and hole blocking
Improved H-2-generation performance of Pt/CdS photocatalyst by a dual-function TiO2 mediator for effective electron transfer and hole blocking
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DOI：
10.1016/j.ceramint.2019.02.018
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发表时间：
2019
影响因子：
5.2
通讯作者：
Tang Hua
中科院分区：
文献类型：
--
作者：
Yu Huogen;Huang Ying;Gao Duoduo;Wang Ping;Tang Hua
贵金属助催化剂表面改性是提高各种光催化剂光催化效率的有效途径。然而，考虑到金属助催化剂在光催化剂表面的随机分散，负载贵金属的光催化剂的活性一般表现出有限的提高，因为贵金属也可以作为光生电荷的复合中心。本文成功地将二氧化钛作为一种双功能介体(有效的电子传输和空穴阻挡)引入到铂和硫化镉的界面形成了Pt单键的二氧化钛/硫化镉光催化剂，目的是为了抑制铂活性中心上电子-空穴对的高复合速率。在可见光下，所有Pt单键TiO2CDS的光催化产氢性能都有明显的提高，其中Pt单键TiO2/CDS(8%)的光催化产氢速率最高(294.2 μ/h)，显著高于铂/CDS的光催化产氢率约3.2倍。提出了Pt单键TiO2光催化剂高效产氢的双功能TiO2光催化机理，即Pt单键TiO2光催化剂中的TiO2层不仅作为电子传输层有效地转移光生电子，促进了铂催化剂上的产氢反应，而且还起到了空穴阻挡层的作用，防止了光生电荷在铂活性中心的复合，从而显著提高了最终的产氢活性。
Surface modification with noble metal cocatalysts was proved to be a useful route for boosting photocatalytic efficiency of various photocatalysts. Nevertheless, considering the random dispersion of metallic cocatalysts on the photocatalyst surface, the noble metal-loaded photocatalyst generally shows a limited enhancement of its activity because the noble metals can also work as the recombination sites of photoinduced charges. In this paper, TiO2as a dual-function mediator (for effective electron transport and hole block) is successfully introduced into the interface of Pt and CdS to form Ptsingle bondTiO2/CdS photocatalyst, with an aim of suppressing the high recombination rate of electron-hole pairs on the Pt active sites. Under visible light, all the prepared Ptsingle bondTiO2/CdS displayed distinctly enhanced photocatalytic hydrogen-generation performance and the Ptsingle bondTiO2/CdS(8%) attains the highest photocatalytic H2-production rate (294.2 μmol/h), a value significantly higher than that of Pt/CdS about 3.2 time. A dual-function TiO2-mediated mechanism was put forward to account for the superior hydrogen production of Ptsingle bondTiO2/CdS photocatalyst, namely, the TiO2layer in the Ptsingle bondTiO2/CdS not only works as electron-transport layers to effectively transfer photogenerated electrons to promote the H2-production reaction on Pt cocatalysts, but also acts as hole-block layer to prevent the possible recombination of photogenerated charges on the Pt active sites, resulting in a distinct improvement of final H2-generation activity.