原位构建W18O49-CNT-BiOBr阶梯状材料及其界面电荷分离增强特性

In-situ construction of W18O49-CNT-BiOBr step-scheme material with enhanced interfacial charge separation characteristics

  • 摘要: 环境污染与能源短缺极大影响着人类健康和社会发展。提高半导体的光生载流子迁移/分离效率仍是实现光电灵敏转化和污染有效净化的关键。以WCl6为原料,采用溶剂热法制备出氧化钨纳米线(W18O49);随后将其与碳纳米管(CNT)和溴化钾水溶液超声分散,再逐滴加入到含硝酸铋的醋酸中,利用一步溶液法,室温下原位反应出具有氧空位调控的氧化钨-碳纳米管-溴氧化铋阶梯状材料(W18O49-CNT-BiOBr)。具有等离子体效应的W18O49-CNT-BiOBr展现出增强的太阳光吸收效率、光电响应能力和光催化降解污染物活性(10 mg W18O49-CNT-BiOBr在20 min内可降解约99.8%的20 mg/L罗丹明B(RhB),明显优于纯W18O49和BiOBr的72.9%和55.8%),并表现出一定的自供电光响应能力。进一步研究表明:W18O49-CNT-BiOBr中界面间光生载流子分离和输运效率明显增强,这可能主要与W18O49-CNT-BiOBr阶梯状异质结构的构筑、氧空位的引入以及协同作用有关;而W18O49-CNT-BiOBr中产生的超氧自由基在光催化降解RhB中发挥了关键作用。

     

    Abstract: Environmental pollution and energy shortages significantly had affected human health and social development. Improving the photogenerated carrier separation/transfer efficiency of semiconductors remained crucial for achieving efficient photoelectric conversion and effective pollution purification. Using tungsten hexachloride as the raw material, tungsten oxide nanowires (W18O49) were firstly prepared by solvothermal method. Subsequently, the W18O49 nanowires were ultrasonically dispersed with carbon nanotubes (CNTs) in an aqueous potassium bromide solution, which was then added dropwise into acetic acid containing bismuth nitrate. By employing one-step solution-phase method, a W18O49-CNT-BiOBr step-scheme material with oxygen vacancy modulation was synthesized via in-situ reaction at room temperature. This W18O49-CNT-BiOBr with plasmonic effects demonstrated significantly enhanced solar light absorption efficiency, photoelectric response capability, and photocatalytic activity for pollutant degradation, and displayed a certain level of self-powered photoelectric response capability. Within 20 min, the degradation rate of 20 mg/L Rhodamine B (RhB) achieved approximately 99.8% with 10 mg W18O49-CNT-BiOBr, which was notably superior to that of pure W18O49 (72.9%) and BiOBr (55.8%). Further studies revealed that the separation and transport efficiency of photogenerated carriers in W18O49-CNT-BiOBr was significantly enhanced, which were mainly related to the construction of W18O49-CNT-BiOBr heterostructure, the introduction of oxygen vacancy and their synergistic effects among the components. Additionally, the superoxide radicals generated in W18O49-CNT-BiOBr heterostructure played a crucial role in the photocatalytic degradation of RhB.

     

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