Unraveling the catalytic performance of RuO(1 1 0) for highly-selective ethylene production from methane at low temperature: Insights from first-principles and microkinetic simulations.

Despite significant progress in low-temperature methane (CH) activation, commercial viability, specifically obtaining high yields of C/C products, remains a challenge. High desorption energy (>2 eV) and overoxidation of the target products are key limitations in CH utilization. Herein, we employ first-principles density functional theory (DFT) and microkinetics simulations to investigate the CH activation and the feasibility of its conversion to ethylene (CH) on the RuO (1 1 0) surface. The CH activation and CH dehydrogenation processes are thoroughly investigated, with a particular focus on the diffusion of surface intermediates. The results show that the RuO (1 1 0) surface exhibits high reactivity in CH activation (E = 0.60 eV), with CH and CH are the predominant species, and CH being the most mobile intermediate on the surface. Consequently, self-coupling of CH* species via CC coupling occurs more readily, yielding CH, a potential raw material for the chemical industry. More importantly, we demonstrate that the produced CH can easily desorb under mild conditions due to its low desorption energy of 0.97 eV. Microkinetic simulations based on the DFT energetics indicate that CH activation can occur at temperatures below 200 K, and CH can be desorbed at room temperature. Further, the selectivity analysis predicts that CH is the major product at low temperatures (300-450 K) with 100 % selectivity, then competes with formaldehyde at intermediate temperatures in the CH conversion over RuO (1 1 0) surface. The present findings suggest that the RuO (1 1 0) surface is a potential catalyst for facilitating ethylene production under mild conditions.