钴
甲醇
甲烷
催化作用
化学
金属有机骨架
铈
催化循环
无机化学
有机化学
吸附
作者
Neha Antil,Manav Chauhan,Naved Akhtar,Rajashree Newar,Wahida Begum,Jaideep Malik,Kuntal Manna
出处
期刊:ACS Catalysis
日期:2022-08-31
卷期号:12 (18): 11159-11168
被引量:12
标识
DOI:10.1021/acscatal.2c02823
摘要
Developing highly efficient catalysts for chemoselective oxidation of methane to methanol under mild conditions is a grand challenge. We report the successful design and synthesis of a heterogeneous single-site cobalt hydroxide catalyst [Ce-UiO-Co(OH)] supported by the nodes of a cerium metal–organic framework (Ce-UiO-66 MOF), which is efficient in partial methane oxidation using hydrogen peroxide at 80 °C, giving an extraordinarily high methanol yield of 2166 mmol gcat–1 in 99% selectivity with a turnover number of 3250. The Ce-UiO-Co catalyst is significantly more active and selective than its iso-structural zirconium analogue Zr-UiO-Co in methane to methanol conversion. Experimental and computational studies suggest the formation of the CoIII(η2-hydroperoxide) intermediate coordinating with one μ4-O– and two neutral carboxylate oxygens of Ce4+ oxo nodes within the pores of Ce-UiO-66, which undergoes σ-bond metathesis with the methane C–H bond in the turnover limiting step of the catalytic cycle. The significantly lower activation energy of Ce-UiO-Co than Zr-UiO-Co is due to the highly electron-deficient nature of the cobalt ion of the Co(η2-O2H) species supported by the Ce-UiO nodes, which promotes facile C–H activation of methane via σ-bond metathesis. This MOF-based catalyst design holds promise in developing molecular electrophilic abundant metal catalysts for chemoselective functionalization of saturated hydrocarbons.
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