时间分辨热化学原位XAFS方法  

Time-resolved thermochemical in-situ XAFS methodology

作　　者：顾颂琦[1,2,3] 孙凡飞 韦尧 宋兴飞 南兵 李丽娜 黄宇营[1,2] GU Songqi;SUN Fanfei;WEI Yao;SONG Xingfei;NAN Bing;LI Lina;HUANG Yuying(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China;University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory on Resources Chemicals and Materials,Shenyang University of Chemical Technology,Shenyang 110142,Liaoning,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院上海高等研究院,上海201204 [3]中国科学院大学,北京100049 [4]沈阳化工大学特色资源化工与材料教育部重点实验室,辽宁沈阳110142

出　　处：《化工进展》2024年第7期3747-3755,共9页Chemical Industry and Engineering Progress

基　　金：国家重点研发计划“催化科学”重点专项(2021YFA1500502);国家自然科学基金青年基金(12205359);国家自然科学基金战略研究类(22242018);“上海市科技创新行动计划”启明星项目(扬帆专项)(23YF1453700)。

摘　　要：为了利用X射线吸收精细结构(X-ray absorption fine structure,XAFS)谱学技术开展热化学反应动力学研究,在上海光源X射线吸收精细结构谱学线站(BL14W1)开展了时间分辨热化学原位XAFS方法的研究。采用自主研制的数据采集设备解决了时间分辨XAFS技术中不同类型信号同步触发和同步采集的问题,实现了数据间的精准匹配。在单色器转速为720"/s、数据采集设备采样率为2MS/s、数据长度为1200eV的条件下,获得了一个9.6s的Cu标样的数据谱,通过与常规XAFS数据和标准XAFS数据进行对比,结果表明本文得到的时间分辨XAFS实验系统具有良好的准确性、分辨率和信噪比。在此基础上,进一步结合线站自主研制的原位装置开展了时间分辨热化学原位XAFS方法,并利用高温常压原位装置开展了CuO还原为金属Cu的验证性实验。在230℃恒温氢气气氛下30min内观测到Cu吸收边能量逐渐向低能量处偏移,同时它位于8998eV的主峰强度逐渐减弱并且劈裂为双峰结构,出现明显的金属Cu的特征。实验结果表明此方法达到了捕获物质动态演化过程的预期目的,在拓展XAFS谱学实验平台的同时,为热化学反应的动力学过程研究提供了一种强大的实验手段。In order to study thermochemical reaction kinetics with XAFS(X-ray absorption fine structure)technology,a time-resolved in-situ XAFS methodology was developed at the BL14W1 beamline at Shanghai Radiation Facility.A dedicated data acquisition device was made to solve the problem of synchronous triggering and acquisition of different types of signals in time-resolved XAFS technology,achieving accurate matching between data.A 9.6-second Cu standard sample data spectrum was obtained under the conditions of the monochromator speed of 720"/s,the data acquisition device sampling rate of 2MS/s,and the data length of 1200eV.By comparing it with conventional XAFS data and standard XAFS data,the results showed that the time-resolved XAFS experimental system developed in this paper had good accuracy,resolution,and signal-to-noise ratio.On this basis,the time-resolved thermochemical in-situ XAFS method was further developed in combination with in-situ cells independently developed at the BL14W1 beamline.It was observed that the absorption edge energy of Cu gradually shifted to the low energy,while the main peak intensity at 8998eV gradually weakened and split into a bimodal structure showing obvious characteristics of metallic Cu within 30 minutes under a constant temperature hydrogen atmosphere at 230℃.This indicates the methodology has achieved the expected goal of capturing the dynamic evolution process of substances.On one hand,it has expanded the XAFS spectroscopy experimental platform.On the other hand,it provides a powerful experimental tool for studying the kinetic processes of thermochemical reactions.

关 键 词：时间分辨 X射线吸收精细结构 原位装置 热化学 反应动力学 

分 类 号：TL99[核科学技术—核技术及应用]