铈锆固溶体Ce_(0.25)Zr_(0.75)O_(2)光热协同催化CO_(2)与甲醇合成DMC  

Photothermal catalysis synthesis of DMC from CO_(2) and methanol over Ce_(0.25)Zr_(0.75)O_(2) solid solution

作　　者：郑谦 官修帅 靳山彪 张长明 张小超[1] ZHENG Qian;GUAN Xiushuai;JIN Shanbiao;ZHANG Changming;ZHANG Xiaochao(College of Chemical Engineering and Technology,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China;College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学化学工程与技术学院,山西太原030024 [2]太原理工大学矿业工程学院,山西太原030024

出　　处：《化工进展》2023年第S01期319-327,共9页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(21978196,21978187,22008167);中国博士后科学基金(2022M712342);山西省自然科学基金(20210302124336,20210302123178)。

摘　　要：采用溶胶-凝胶法合成不同铈含量的ZrO_(2)催化剂,用于光热协同催化CO_(2)与甲醇直接合成碳酸二甲酯(DMC)。实验发现,光热催化的DMC产率明显高于热催化,且Ce_(0.25)Zr_(0.75)O_(2)具有最高DMC产率3.084mmol/g,是纯ZrO_(2)的1.9倍。XRD和TEM分析表明:Ce原子掺入ZrO_(2)晶格形成铈锆固溶体同时增加其表面氧空位浓度,提高吸附CO_(2)能力;固溶体的纳米尺寸减小、比表面积增大和介孔结构丰富,有利于CO_(2)扩散。能带结构和光吸收光谱表明:铈锆固溶体光响应范围拓宽且有效利用率提高;氧空位辅助窄带隙特征可促使光生载流子有效分离,允许更多光生电子和空穴参与CO_(2)及甲醇的活化,加之固溶体表面酸碱位点的协同作用,最终实现高效率高选择性合成DMC。最后,提出了铈锆固溶体光热催化CO_(2)与甲醇合成DMC的反应机理,为光协同热催化合成DMC的研究提供良好的理论基础和实验数据。ZrO_(2) catalysts with different Ce contents were synthesized by sol-gel method and used for carrying out to achieve the photothermal catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2) and methanol.Experimental results revealed that the DMC yield via photothermal catalysis was obviously higher than single thermal catalysis,and Ce_(0.25)Zr_(0.75)O_(2) had the best effect with the DMC yield of 3.084mmol/g,which was 1.9 times that of pure ZrO_(2).XRD and TEM analysis results showed that Ce atoms were doped into the crystal lattice of ZrO_(2),which led to the formation of cerium-zirconium solid solution and the increasing concentration of surface oxygen vacancies,improving the CO_(2) adsorption capacity.The solid solution had smaller nano size and larger specific surface area,and its formation of mesoporous structure was more conducive to CO_(2) diffusion.The energy band structure and optical absorption spectra confirmed that the photoresponse of solid solution was widened and the light utilization efficiency was raised.Besides,with the assistance of oxygen vacancy in the narrow band gap prompts,the efficient separation of photo-generated carriers would provide more photo-generated electrons and held for activating methanol and CO_(2),and combine with acid-base sites on the surface of solid solution,realizing the highly efficient synthesis and selectivity of DMC.Finally,the reaction mechanism of photothermal catalysis synthesis of DMC from CO_(2) and methanol over Ce_(0.25)Zr_(0.75)O_(2) solid solution was proposed,which should provide excellent theoretical basis and experimental data for the research and development on the photothermal catalytic synthesis of DMC.

关 键 词：二氧化碳 碳酸二甲酯 光热协同催化 铈锆固溶体 氧空位 

分 类 号：TQ032[化学工程]