甲烷直接催化氧化制备甲醇近期研究进展北大核心CSCD

甲烷合成甲醇的方法包括间接法和直接催化氧化(DMTM)法,但是间接法对设备要求高,且甲烷转化率与甲醇选择性均不理想,DMTM法可通过一步反应高选择性制备甲醇,有巨大的应用潜力。对于甲烷DMTM法合成甲醇,均相催化体系通常需要特殊反应介质与贵金属催化剂相结合,虽然反应效率高,但对反应设备有腐蚀性,产物不易分离,应用前景差。液相-异相催化一般使用H_(2)O_(2)作为氧化剂,Au、Pd、Fe和Cu等金属元素作为催化剂主要活性组分,·OH是主要的氧化活性物,可在低温下实现甲烷的活化氧化。因此,异相催化体系是目前研究的主流。气相-异相催化主要使用O_(2)和N_(2)O为氧化剂,前者氧化性更强,后者对于产品选择性更好,此外,厌氧体系中H_(2)O也可直接作为氧供体,常用Cu、Fe、Rh等元素作为催化剂。沸石分子筛是使用最广泛的载体,金属氧化物、金属有机骨架化合物(MOFs)和石墨烯也均有涉及,多金属协同催化已经取得了很好的效果。本文主要总结与概述了热催化甲烷直接催化氧化制备甲醇的近年相关研究,并对今后的研究方向做出了展望。

Recent Advances in Direct Oxidation of Methane to Methanol

The methods for synthesizing methanol from methane include indirect method and direct catalytic oxidation method， but the indirect method requires high equipment， and the methane conversion rate and methanol selectivity are not ideal. Direct catalytic oxidation method （DMTM） can produce methanol with high selectivity through a one-step reaction， and has huge application potential. For DMTM， the homogeneous catalytic system usually requires a special reaction medium combined with a precious metal catalyst. Although the reaction efficiency is high， it is corrosive to the reaction equipment， the product is not easy to separate， and the application prospect is poor. Liquid phase-heterogeneous catalysis generally uses H₂O₂ as the oxidant， Au， Pd， Fe， Cu and other metal elements as the main active component of the catalyst， and·OH is the main oxidation active substance， which can be used at low temperature to realize the activation and oxidation of methane. Therefore， heterogeneous catalytic systems are currently the mainstream of research. Gas phase-heterogeneous catalysis mainly uses O₂ and N₂O as oxidants. The former is more active， and the latter is more selective for products. In addition， H₂O in anaerobic systems can also be directly used as oxygen donors， commonly Cu， Fe， Rh， etc. elements are used as catalysts. Zeolite molecular sieves are the most widely used support， and metal oxides， metal organic frameworks （MOFs） and graphene are also involved. Multi-metal synergistic catalysis has achieved good results. This article mainly summarizes the research on the direct catalytic oxidation of thermally catalyzed methane to methanol in recent years， and prospects for future research directions.