摘要
The synthetic path of a catalyst determines its morphology,species,and performance,and in-situ monitoring the catalyst formation process is fascinating and challenging.Herein,a newly developed synchrotron radiation smallangle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined technique was used to in-situ monitor the isothermal-isobaric synthesis process of CO_(2)-assisted(BiO)_(2)CO_(3)(BOC)photocatalyst,and the atomic near-neighbor structure,crystalline structure and nanoscale particle size evolution with reaction time were simultaneously captured.The results show that both polyvinyl pyrrolidone and CO_(2)formed uniformly-distributed nano-sized scatterers in the Bi-based precursor solution,presenting short-range ordered structures to a certain extent.The as-prepared BOC catalytic particles underwent the evolution process of initial Bi(OH)3 precipitate,early-stage formed KBiO_(2)molecules,intermediate amorphous(BiO)4CO3(OH)2 nanoparticles,and finally crystallized flower-like BOC particles self-assembled by nanosheets.The flower-like BOC particles,Bi/BOC composite,and Bi nanospheres were further prepared with different synthesis paths.Flower-like BOC particles showed the best photocatalytic degradation performance of RhB.Scavenger experiment and theoretical calculation revealed the photocatalytic mechanisms of BOC.This work has implications for path-dependent synthesis of other catalysts.
催化剂的合成路径决定其形态、种类和性能,原位监测催化剂形成过程极具吸引力,且充满挑战.本文利用新开发的同步辐射SAXS/XRD/XAFS联用技术,原位监测了CO_(2)辅助下(BiO)_(2)CO_3(BOC)光催化剂的等温等压合成过程,同步获取了其原子近邻结构、晶体结构和纳米尺度粒径随反应时间的演化.研究结果揭示铋基前驱体溶液中,聚乙烯吡咯烷酮(PVP)和CO_(2)均形成均匀分布的纳米尺寸散射体,并呈现出一定程度上的短程有序结构;所形成的BOC光催化剂经历了初始Bi(OH)_3沉淀、早期形成KBiO_(2)分子、中间非晶态(BiO)_(4)CO_3(OH)_(2)纳米粒子、到最终结晶纳米片自组装花状BOC颗粒的演化过程.本文还进一步采用不同合成途径分别制备了花状BOC颗粒、Bi/BOC复合材料和Bi纳米球,花状BOC颗粒呈现出最优的RhB光催化降解性能,清除剂实验和理论计算揭示了BOC的光催化机制.这项工作对其他催化剂的路径依赖合成具有参考价值.
作者
Yunpeng Liu
Shunzheng Zhao
Jiajun Zhong
Jianglong Liu
Baotong Chen
You Liao
Lei Yao
Zhongjun Chen
Buxing Han
Zhonghua Wu
刘云鹏;赵顺征;钟佳君;刘江龙;陈宝通;廖友;姚磊;陈中军;韩布兴;吴忠华(Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;University of Science and Technology Beijing,Beijing 100083,China;University of Chinese Academy of Sciences,Chinese Academy of Sciences,Beijing 100049,China;College of Science,China University of Petroleum(Beijing),Beijing 102249,China;Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China)
基金
supported by the National Natural Science Foundation of China(12305372)
the National Key R&D Program(2017YFA0403001 and 2022YFA1603802)of China。
