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Promoting superoxide generation in Bi2WO6 by less electronegative substitution for enhanced photocatalytic performance: an example of Te doping
Catalysis Science & Technology ( IF 5 ) Pub Date : 2021-07-08 , DOI: 10.1039/d1cy00739d
Anurak Waehayee 1, 2 , Chawit Pongsawakul 1 , Apinya Ngoipala 3 , Praphaiphon Phonsuksawang 1, 2 , Arreerat Jiamprasertboon 1, 2 , Suttipong Wannapaiboon 4 , Hideki Nakajima 4 , Teera Butburee 5, 6 , Suwit Suthirakun 1, 6 , Theeranun Siritanon 1, 6
Affiliation  

Because of their interesting properties and relatively high stability, Bi2WO6 photocatalysts have been widely investigated. Several strategies have been proven effective in improving their performance. Here, we investigate the enhancement of Bi2WO6 photocatalytic activity via Te substitution by means of experiments and first-principles calculations. A maximum of 5 at% can be successfully doped into the Bi2WO6 lattice with no impurity by a facile hydrothermal method. Replacing W6+ with Te6+ does not affect the crystal structure but evidently changes the samples' morphologies and electronic structure. The plate-like structure of Bi2WO6 is altered to a thinner nanosheet, which eases the carrier diffusion and increases the surface active sites. The extra Te 5s state increases the density of states at the bottom of the conduction band and consequently increases the carrier mobility. As a result, carrier recombination is significantly reduced upon Te doping. Moreover, the lower electronegativity of the Te dopant shifts the band edge potential towards more negative values which additionally enables the generation of superoxide radicals. As a result, an optimum doping content of 2.5 at% Te gives rise to 48 times higher Rhodamine B photodegradation compared to pure Bi2WO6. The obtained results provide insights into the effects of doping, specifically the effects of the dopants' electronegativity, on the photocatalytic activity which could be a very effective strategy to improve other related oxide-based photocatalysts.

中文翻译:

通过较少的负电取代促进 Bi2WO6 中超氧化物的产生以提高光催化性能:Te 掺杂的一个例子

由于其有趣的性质和相对较高的稳定性,Bi 2 WO 6光催化剂已被广泛研究。有几种策略已被证明可有效提高其性能。在这里,我们通过实验和第一性原理计算研究了通过Te 取代增强 Bi 2 WO 6光催化活性。通过简便的水热法,最多可以将 5at% 成功地掺杂到无杂质的 Bi 2 WO 6晶格中。更换W¯¯ 6+用TE 6+不影响晶体结构,但明显改变样品的形貌和电子结构。Bi 2 WO 6的板状结构被改变为更薄的纳米片,这减轻了载流子扩散并增加了表面活性位点。额外的 Te 5s 态增加了导带底部的态密度,从而增加了载流子迁移率。结果,Te掺杂后载流子复合显着减少。此外,Te 掺杂剂的较低电负性使带边电位向更负的值移动,这额外地能够产生超氧自由基。因此,与纯 Bi 相比,2.5 at% Te 的最佳掺杂含量使罗丹明 B 的光降解率提高了 48 倍2 WO 6.获得的结果提供了对掺杂的影响的见解,特别是掺杂剂的电负性对光催化活性的影响,这可能是改进其他相关氧化物基光催化剂的非常有效的策略。
更新日期:2021-08-17
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