Ojha Niwesh, Bajpai Abhinav, Kumar Sushant
Gas-Solid Interaction Laboratory, Department of Chemical and Biochemical Engineering, Indian Institute of Technology Patna, Bihta, Patna 801 106, Bihar, India.
Gas-Solid Interaction Laboratory, Department of Chemical and Biochemical Engineering, Indian Institute of Technology Patna, Bihta, Patna 801 106, Bihar, India.
J Colloid Interface Sci. 2021 Mar;585:764-777. doi: 10.1016/j.jcis.2020.10.056. Epub 2020 Oct 20.
When two semiconductors are electronically coupled, their photocatalytic performance can be greatly enhanced. Herein, we formed a heterostructure between CuO and SnS/SnO nanocomposite using a solvothermal reactor, which reduced CO by HO at ambient conditions to produce CO, H and CH. With inclusion of CuO, apparent quantum yield, a measure of photoactivity, has increased from 7.16% to 8.62%. Also, the selectivity of CH over CO was approximately 1.8-times higher than that of SnS/SnO. Interestingly, the as-synthesized catalysts were able to fix N to NH under light illumination at ambient conditions. Dissecting the mechanism into basic steps, it is shown that oxygen vacancies within the catalysts act as trapping sites for photo-induced charge carriers which strongly influenced the reactivity and selectivity of product. Additionally, oxygen vacancies act as active sites to chemisorb nitrogen molecules, which follow associative steps to generate NH. In absence of sacrificial agent, the NH generation rate was66.35μmol.gh for CuO/SnS/SnO, which is 1.9-fold higher than SnS/SnO. Formation of a p-n heterojunction between CuO and SnS/SnO nanocomposite offered favorable photoreductive potentials and high stability, mainly owing to their intimate interfacial contact. The results clearly illustrate a promising strategy to use oxygen vacancies rich heterostructure for wide application in photocatalysis.
当两种半导体进行电子耦合时，它们的光催化性能会得到极大增强。在此，我们利用溶剂热反应器在CuO与SnS/SnO纳米复合材料之间形成了异质结构，该结构在环境条件下能使HO还原CO以生成CO、H和CH。加入CuO后，作为光活性度量的表观量子产率从7.16%提高到了8.62%。此外，CH相对于CO的选择性比SnS/SnO大约高1.8倍。有趣的是，所合成的催化剂在环境条件下光照时能够将N固定为NH。将该机理剖析为基本步骤可知，催化剂中的氧空位充当光生电荷载流子的捕获位点，这对产物的反应性和选择性有强烈影响。此外，氧空位充当化学吸附氮分子的活性位点，氮分子通过缔合步骤生成NH。在没有牺牲剂的情况下，CuO/SnS/SnO的NH生成速率为66.35μmol·g⁻¹·h⁻¹，比SnS/SnO高1.9倍。CuO与SnS/SnO纳米复合材料之间形成的p-n异质结提供了有利的光还原电位和高稳定性，这主要归因于它们紧密的界面接触。结果清楚地说明了利用富含氧空位的异质结构在光催化中广泛应用的一种有前景的策略。
