Active Structure of Zirconia-Supported Ruthenium Oxide Catalyst for Low-Temperature Oxidation of Methanol to Methyl Formate

采用ZrO2负载的RuOx催化剂在低温(如373 K)下催化甲醇选择氧化合成甲酸甲酯,发现RuOx的结构可显著影响反应速率和产物选择性.在相近的甲醇转化率下,RuO42-物种的催化活性和对甲酸甲酯的选择性明显高于RuO2物种,表明在ZrO2表面构筑高活性高选择性的RuO42-结构有利于获得高的甲酸甲酯产率.The oxidation of methanol to methyl formate at low temperature (373 K) over the ZrO2-supported RuOx catalyst was studied. The methanol oxidation rate and product selectivity strongly depend on the RuOx structure, which is changed in the Ru surface density range of 0.2-3.8 Ru/nm(2). The RuOx structure evolves from isolated RuO42- species below 0.4 Ru/nm(2) to RuO2 clusters above 1.9 Ru/nm(2). Such structural evolution with increasing Ru surface density leads to a decrease in the methanol oxidation rate on per Ru atom and on per exposed Ru atom (i.e. turnover rate). This reveals that RuO42- species are more reactive than RuO2 species, which is consistent with the higher reducibility of the RuO42- structure. These RuO42- species are also more selective than the RuO2 species for the methyl formate formation at similar methanol conversion; a similar to 96% methyl formate selectivity (at similar to 15% methanol conversion) was attained at 0.2 Ru/nm(2) with predominant RuO42- structure. These findings suggest that the highly active and selective RuO42- structure is required for achieving high methyl formate productivity.国家自然科学基金; 教育部留学回国人员科研启动基金; 教育部跨世纪优秀人才培养计划http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000241931800002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701SCI(E)中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)310840-8422