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The direct, nonoxidative conversion of methane on a silica‐confined single‐atom iron catalyst is a landmark discovery in catalysis, but the proposed gas‐phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe1©SiC2), followed by C−C coupling and hydrogen transfer to produce the main product (ethylene) via a key −CH−CH2 intermediate. We find a quasi Mars–van Krevelen (quasi‐MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe1©SiO2 and this surface process is identified to be more plausible than the alternative gas‐phase reaction mechanism. [ABSTRACT FROM AUTHOR]

The gas-phase reactions of sulfuricacid catalyzed hydrolysis offormaldehyde and formaldehyde with sulfuric acid and H2SO4···H2O complex are investigatedemploying the high-level quantum chemical calculations with M06-2Xand CCSD(T) theoretical methods and the conventional transition statetheory (CTST) with Eckart tunneling correction. The calculated resultsshow that the energy barrier of hydrolysis of formaldehyde in gasphase is lowered to 6.09 kcal/mol from 38.04 kcal/mol, when the sulfuricacid is acted as a catalyst at the CCSD(T)/aug-cc-pv(T+d)z//M06-2X/6-311++G(3df,3pd)level of theory. Furthermore, the rate constant of the sulfuric acidcatalyzed hydrolysis of formaldehyde combined with the concentrationsof the species in the atmosphere demonstrates that the gas-phase hydrolysisof formaldehyde of sulfuric acid catalyst is feasible and could beof great importance for the sink of formaldehyde, which is in previouslyforbidden hydrolysis reaction. However, it is shown that the gas-phasereactions of formaldehyde with sulfuric acid and H2SO4···H2O complex lead to the formationof H2C(OH)OSO3H, which is of minor importancein the atmosphere. [ABSTRACT FROM AUTHOR]