Selective Oxidation of Methane to Methanol over Au/H-MOR

Abstract

Selective oxidation of methane to methanol by dioxygen (O 2 ) is an appealing route for upgrading abundant methane resource and represents one of the most challenging reactions in chemistry due to the overwhelmingly higher reactivity of the product (methanol) versus the reactant (methane). Here, we report that gold nanoparticles dispersed on mordenite efficiently catalyze the selective oxidation of methane to methanol by molecular oxygen in aqueous medium in the presence of carbon monoxide. The methanol productivity reaches 1300 μmol g cat −1 h −1 or 280 mmol g Au −1 h −1 with 75% selectivity at 150 °C, outperforming most catalysts reported under comparable conditions. Both hydroxyl radicals and hydroperoxide species participate in the activation and conversion of methane, while it is shown that the lower affinity of methanol on gold mainly accounts for higher methanol selectivity.

Spatiotemporal Heterogeneity of Temperature and Catalytic Activation within Individual Catalyst Particles

“…Heterogenous catalysis by porous solid catalysts such as zeolites is of great importance in the efficient and sustainable conversion of carbon-based resources (e.g., crude oil, coal, biomass, natural gas, and CO 2 ) for producing valuable chemicals. − The essence of catalyst development lies in the optimized active sites , and anticipated reaction rates, enabling on-purpose chemical reactions to proceed with high efficiency, mild conditions, and low cost. Temperature, a direct indicator of the kinetic energy and collisional frequency of reacting molecules, determines the kinetics and thermodynamics of chemical reactions. , In real applications, measuring the reactor temperature has become a common practice to monitor the apparent reaction performance of bulk catalysts including but not limited to the reaction rate, heat and mass transfer, reactant conversion, and product yields. , In practical chemical industries, catalytic active sites are commonly sealed in grain to reduce the mass transfer resistance or make catalyst particles readily fluidized. − Despite its significance, temperature as the most decisive operating parameter in catalysis, however, has yet to be carefully studied at the single catalyst particle.…”

Sulfite-Enhanced Aerobic Methane Oxidation to Methanol over Reduced Phosphomolybdate

“…However, aerobic partial methane oxidation to methanol faces many challenges. Methanol is more reactive than methane, making it difficult to simultaneously achieve high methane conversion and high methanol selectivity. − Numerous catalysts have been developed, most of which require the addition of coreductants like CO or H 2 . − For example, PdAu alloy nanoparticles confined within hydrophobically modified ZSM-5 have been developed for methane oxidation using in situ generated H 2 O 2 from H 2 and O 2 at 70 °C . The Au/ZSM-5 catalyst is further utilized for selective methane oxidation just using molecular O 2 in the temperature range of 120 to 240 °C .…”

Coupling of electrocatalytic CO2 reduction and CH4 oxidation for efficient methyl formate electrosynthesis

“…CH 4 is an abundant gas fuel resource and a greenhouse gas. 11 The catalytic conversion of CH 4 has been extensively investigated to use natural gas resources; 12 however, the inert chemical nature of CH 4 typically requires high temperatures for activation. 13 For example, the dry reforming of methane can convert CH 4 and CO 2 into syngas 14 but the energy consumption is high and product selectivity is mainly limited to CO and H 2 .…”