Zheng Jia, Liu Jincheng, Feng Xuyang, Liu Jiarong, Zong Shuang, Liu Lingling, Fang Yanxiong
Guangdong University of Technology, School of Light Industry & Chemical Engineering, Guangzhou Key Lab Clean Transport Energy Chemistry, Guangzhou 510006, China; Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory, Jieyang 515200, China.
Guangdong University of Technology, School of Light Industry & Chemical Engineering, Guangzhou Key Lab Clean Transport Energy Chemistry, Guangzhou 510006, China; Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory, Jieyang 515200, China.
J Colloid Interface Sci. 2023 Dec;651:304-318. doi: 10.1016/j.jcis.2023.07.172. Epub 2023 Jul 28.
The difficulty of achieving both high conversion rate and high selectivity is a huge challenge in the catalytic aerobic oxidation of cyclohexane. In this paper, bismuth tungstate-bismuth oxychloride (BiWO-BiOCl) nanoflower heterojunctions prepared via a one-step solvothermal process were applied in the photo-thermo synergetic catalytic oxidation of cyclohexane in the dried air. With the addition of little water at different reaction temperature, the ratio of bismuth to tungsten and the mass ratio of BiWO to BiOCl can be precisely tailored in the nanoflower sphere composites with thin nanosheets. Their microscopic morphology, elemental composition, crystal structure, and photoelectrochemical characteristics were explored by different characterization methods. The BiWO-BiOCl composites possessed poor photocatalytic and thermal performances with the low conversion rates of 1.43% and 2.68%, respectively. However, through the photo-thermo catalytic oxidation process, an exceptional conversion rate of 13.32% was achieved with excellent selectivity of 99.22% for cyclohexanone and cyclohexanol (KA oil) using the same BiWO-BiOCl composites. This superior performance outstrips BiWO flowers, BiOCl nanosheets and BiWO-BiOCl composites with other compounding ratios. The creation of a high-low heterojunction in the BiWO-BiOCl composite was confirmed by band energy analysis. The opto-electronic analysis, band energy analysis, sacrifice experiments, and active radical analysis were employed to elucidate the mechanism for the exceptional photo-thermo catalytic performance in detail. This work offers an exploratory solution to the challenges of high energy consumption and the difficulty in simultaneously achieving high selectivity and high conversion rates in cyclohexane oxidation, thus holding significant value.
在环己烷的催化好氧氧化反应中，要同时实现高转化率和高选择性是一项巨大的挑战。本文中，通过一步溶剂热法制备的钨酸铋-氯氧化铋（BiWO-BiOCl）纳米花异质结被应用于干燥空气中环己烷的光热协同催化氧化反应。在不同反应温度下添加少量水，可以精确调整纳米花球复合材料中铋与钨的比例以及BiWO与BiOCl的质量比，该复合材料由薄纳米片组成。通过不同的表征方法对其微观形态、元素组成、晶体结构和光电化学特性进行了探索。BiWO-BiOCl复合材料的光催化和热性能较差，转化率分别仅为1.43%和2.68%。然而，通过光热催化氧化过程，使用相同的BiWO-BiOCl复合材料实现了13.32%的优异转化率，对环己酮和环己醇（KA油）的选择性高达99.22%。这种优异的性能超过了BiWO花、BiOCl纳米片以及其他配比的BiWO-BiOCl复合材料。通过能带能量分析证实了BiWO-BiOCl复合材料中形成了高低异质结。采用光电分析、能带能量分析、牺牲实验和活性自由基分析等方法详细阐明了其优异光热催化性能的机理。这项工作为环己烷氧化过程中高能耗以及难以同时实现高选择性和高转化率的挑战提供了一种探索性解决方案，因而具有重要价值。
