Toward the Computational Discovery of Single-Atom Alloys for the Direct Conversion of Methane to Methanol.

The efficient conversion of methane is crucial for the sustainable utilization of energy resources. The direct oxidation of methane to methanol (MTM) represents a strategically significant route in both the energy and chemical industries. However, the MTM process faces enormous challenges due to the robust stability of methane and the high bond dissociation energy of the C-H bond. Single-atom alloys (SAAs), characterized by unique electronic structures and atomically dispersed active sites, exhibit great potential for driving the MTM reaction with high efficiency and selectivity. Herein, by employing a comprehensive strategy, SAAs with high efficiency for MTM were systematically designed and screened by combining density functional theory calculations, thermodynamic stability, and microkinetic modeling. Five host metals were screened for their oxidant activity, and 23 SAA candidates were then generated by doping 3d-5d transition metal atoms. Multiple thermodynamic descriptors and the dissociation activity toward methane were employed for the screening of SAAs, and four SAAs standing out: Ir1/Cu, Hf1/Cu, Rh1/Cu, and Zr1/Cu. The reaction pathways of MTM and turnover frequencies (TOFs) for methanol formation on these SAAs were investigated, along with their coke resistance, and Ir1/Cu was identified as a promising catalyst through predictive calculations for the oxidative transformation of methane to methanol. This study presents a comprehensive strategy for the design and screening of SAAs, serving as a valuable reference for the theoretical development of highly efficient catalysts for methane conversion.