摘要
通过在还原性气氛中煅烧钌基水滑石前驱体,制备了高度分散于金属氧化物纳米片上的钌纳米颗粒(MgAlRu-500R).利用X射线衍射(XRD)、高分辨透射电子显微镜(HRTEM)、X射线光电子能谱(XPS)和紫外-可见-近红外漫反射光谱(UV-Vis-NIR DRS)对MgAlRu-500R的晶体结构、形貌、元素组成和光学特性进行分析表征.基于流动相反应体系研究了MgAlRu-500R催化剂在常压条件下的光热催化合成氨性能.结果表明,MgAlRu-500R可以仅依靠光照升温至300℃以上,并驱动光热催化合成氨反应.在380℃下,MgAlRu-500R光热催化合成氨速率高达3.0 mmol·g^(-1)·h^(-1),显著高于相同温度下的热催化合成氨速率(1.5 mmol·g^(-1)·h^(-1)).动力学分析(包括表观活化能和动力学反应级数的测定)结果表明,优异的光热催化合成氨活性是因为光激发加速了N2解离,进而降低了反应活化能.
The metal oxide nanosheet-supported Ru nanoparticles(MgAlRu-500R)were prepared via calcining the Ru-based layered double hydroxide(MgAlRu-LDH)in a reductive atmosphere.X-Ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible-near-infrared diffuse reflectance spectroscopy(UV-Vis-NIR DRS)were employed to characterize the crystal structure,morphology,component and optical properties of MgAlRu-500R.The photothermal catalytic performance of MgAlRu-500R for ammonia synthesis was investigated in a flow-type reaction system at normal pressure.The results demonstrated that MgAlRu-500R can be heated up to more than 300℃by light illumination as sole energy source and drived the photothermal catalytic ammonia synthesis reaction.Notably,MgAlRu-500R delivered a high ammonia production of 3.0 mmol·g^(-1)·h^(-1)at 380 oC,markedly exceeding that of thermocatalytic process at the same temperature(1.5 mmol·g^(-1)·h^(-1)).Furthermore,in-depth kinetic analysis(determinations of apparent activation energy and kinetic reaction order)attributes the outstanding catalytic activity to the reduced activation energy caused by photoexcitation-accelerated N_(2) dissociation.This work provides a highly active catalyst with simple preparation method for photothermal ammonia synthesis,which will promote the development of green ammonia synthesis technology.
作者
卞宣昂
周超
赵运宣
张铁锐
BIAN Xuanang;ZHOU Chao;ZHAO Yunxuan;ZHANG Tierui(Key Laboratory of Photochemical Conversion and Optoelectronic Materials,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第6期105-112,共8页
Chemical Journal of Chinese Universities
基金
国家重点基础研究发展计划项目(批准号:2021YFA1500803)
国家自然科学基金(批准号:51825205,52120105002,22102202,22088102,52072382)
中国科学院DNL合作基金(批准号:DNL202016)
中国科学院稳定支持基础研究领域青年团队计划项目(批准号:YSBR-004)
中国博士后科学基金(批准号:BX2021323)资助.
关键词
合成氨
光热催化
层状双金属氢氧化物
钌催化剂
Ammonia synthesis
Photothermal catalysis
Layered double hydroxide
Ruthenium catalyst
