负载Ir单原子和团簇的α-MoC催化剂用于高效催化CO_(2)加氢制CO

Ir Single Atoms and Clusters Supported onα-MoC as Catalysts for Efficient Hydrogenation of CO_(2) to CO

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摘要在高温逆水气变换(RWGS)反应中,开发高活性和高稳定性的金属负载型催化剂还存在巨大挑战。针对此问题,本研究采用溶液蒸发自组装法构建了Ir物种负载于α-Mo C的协同催化剂,结果表明,Ir与α-Mo C的协同效应使其在较宽的温度范围内均有较好的RWGS反应性能。特别是在500℃、0.1 MPa、300000 mL·g^(-1)·h^(-1)的反应条件下,0.5%Ir/MoC催化剂的CO_(2)转化率高达48.4%,接近CO_(2)平衡转化率(49.9%),同时,CO选择性和CO时空收率分别高达94.0%和423.1μmol·g^(-1)·s^(-1),且在100 h之内反应性能几乎没有衰减,具有优异的高温稳定性,此催化性能也超过了大多数文献报道。系列结构表征表明,Ir物种均匀地分散在α-Mo C载体上,其电子较利于转移至α-Mo C而形成金属载体强相互作用,极大地提高了催化稳定性;同时,当Ir负载量高于0.2%(质量分数)时,Ir团簇(Irn)和Ir单原子(Ir1)同时存在,与α-MoC形成了Irn-Ir1-C-Mo协同位点。其中,0.5%Ir/Mo C催化剂拥有较小尺寸的Irn和较多的Ir1,显著地促进了CO_(2)和H2的吸附和活化,并促进了甲酸盐中间体的生成和解离,从而获得了优异的RWGS性能。这项工作为设计和制备高效稳定的CO_(2)利用催化剂提供了一定的参考和指导。 The conversion of CO_(2) into CO via the reverse water gas shift(RWGS)reaction has recently attracted considerable attention owing to the increase in atmospheric CO_(2) emissions.However,metal-supported catalysts easily undergo sintering and become inactive at high temperatures.To fabricate highly active and stable catalysts,molybdenum carbide(MoxC),with properties similar to those of precious metals,has been extensively investigated.In particular,it has been demonstrated that face-centered cubic α-MoC can strongly interact with support metals,rendering it an attractive candidate as a catalyst for the RWGS reaction.Furthermore,it has been previously demonstrated that metallic Ir,with unique electronic properties and a low CO desorption barrier,is active for the RWGS at low temperatures(250-300℃).Accordingly,in this study,a system of Ir species andα-MoC was constructed using a solvent evaporation self-assembly method.The catalytic performance of the Ir/MoC catalysts for the RWGS reaction was considerably superior to that of pureα-MoC over a wide temperature range(200-500°C)owing to the synergistic effect of Ir and α-MoC.The optimal 0.5%Ir/MoC catalyst yielded a CO_(2) conversion of 48.4% at 500℃,0.1 MPa,and 300000 mL·g^(−1)·h^(−1),which was comparable to the equilibrium conversion(49.9%).The CO selectivity and space-time yield of CO over 0.5%Ir/MoC reached 94.0%and 423.1μmol·g^(−1)·s^(−1),respectively,which were higher than most of the previously reported values.Moreover,0.5%Ir/MoC retained its catalytic properties over 100 h and demonstrated excellent stability at high temperatures.Several characterization methods were used to demonstrate that the Ir species supported onα-MoC substrates were highly dispersed.The strong metal-support interaction between Ir and α-MoC,which occurred via electron transfer,considerably improved the stability of the Ir/MoC catalysts.For the Ir/MoC catalysts with Ir loadings>0.2%(mass fraction),Ir single atoms(Ir1)and clusters(Irn)coexisted to create Irn-Ir1-C-Mo

作者卢俊文张书南周浩志黄超杰夏林刘晓放罗虎王慧 Junwen Lu;Shunan Zhang;Haozhi Zhou;Chaojie Huang;Lin Xia;Xiaofang Liu;Hu Luo;Hui Wang(CAS Key Laboratory of Low-Carbon Conversion Science and Engineering,Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Carbon Neutrality,ShanghaiTech University,Shanghai 201203,China)

机构地区中国科学院上海高等研究院中国科学院大学上海科技大学

出处《物理化学学报》 SCIE CAS CSCD 北大核心 2023年第11期131-140,共10页 Acta Physico-Chimica Sinica

基金国家重点研发计划(2022YFA1504800,2022YFA1504702,2022YFB4101900) 国家自然科学基金(22108289,22279158,21905291) 中海油化工与新材料科学研究院(YJSCZX07956YJ) 上海市低碳技术创新功能型平台(E244831E01)资助项目。

关键词逆水煤气变换反应金属-载体相互作用协同效应碳化钼铱基催化剂 Reverse water gas shift reaction Metal-support interaction Synergistic effect Molybdenum carbide Iridium catalyst

分类号 O643 [理学—物理化学]