Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China; Key Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, China.
J Colloid Interface Sci. 2021 May 15;590:387-395. doi: 10.1016/j.jcis.2021.01.066. Epub 2021 Jan 27.
Semiconductor photocatalysis can carry out selective chemical transformations under ambient conditions, mitigating the associated environmental consequences. However, a single semiconductor photocatalyst usually cannot perform the transformations satisfactorily from the aspects of light-absorption, efficiency, and selectivity, etc. To address these challenges, cadmium sulfide (CdS)/titanate hybrid was fabricated by simultaneously growing titanate and CdS and had been comprehensively characterized. The optimized CdS/titanate hybrid can power the highly selective oxidative homocoupling of amines under the irradiation of green light-emitting diodes (LEDs). Specifically, CdS with a narrow bandgap captures green light; the conduction band of titanate activates molecular oxygen (O). The valence band of CdS could ensure the selective oxidative homocoupling of amines in methanol (CHOH). The hybridization between CdS and titanate accounts for the expeditious oxidative homocoupling of amines into imines and the improved stability. Reactive oxygen species (ROS) quenching experiments and in situ electron paramagnetic resonance (EPR) tests suggest that superoxide anion (O) and benzylamine radical are intermediates en route to imines. This work highlights the viability of hybridization of dual semiconductor nanostructures in implementing visible light-powered selective conversions.
半导体光催化可以在环境条件下进行选择性的化学转化，减轻相关的环境后果。然而，从光吸收、效率和选择性等方面来看，单个半导体光催化剂通常无法令人满意地进行这些转化。为了解决这些挑战，通过同时生长钛酸盐和 CdS 制备了硫化镉（CdS）/钛酸盐杂化材料，并对其进行了全面表征。优化后的 CdS/钛酸盐杂化物可以在绿光发光二极管（LED）的照射下，高效选择性地氧化伯胺的偶联。具体来说，具有较窄带隙的 CdS 可以捕获绿光；钛酸盐的导带可以激活分子氧（O）。CdS 的价带可以确保甲醇（CHOH）中伯胺的选择性氧化偶联。CdS 和钛酸盐之间的杂化解释了伯胺迅速氧化偶联成亚胺以及提高的稳定性。活性氧物种（ROS）淬灭实验和原位电子顺磁共振（EPR）测试表明，超氧阴离子（O）和苄胺自由基是生成亚胺的中间体。这项工作突出了双半导体纳米结构杂交在实现可见光驱动选择性转化方面的可行性。
