High-efficiency purification of CH₄ and H₂ energy sources enabled by a phosphotungstic acid-supported Os single-atom catalyst

Methane (CH4) and hydrogen (H-2) show promise as low-carbon energy sources, but their impurities, including H-2 and CO, pose challenges for storage and use. To address these challenges, a robust purification protocol for CH4 and/or H-2, combined with the catalytic conversion of impurities into CO2 and H2O, is a compelling solution. In this work, we investigated 11 phosphotungstic acid (PTA)-supported single-atom catalysts (SACs) by density functional theory (DFT) computations. Os-1/PTA SACs exhibited superior catalytic activity, and the ease of oxidation follows the CO > H-2 > CH4 order. It facilitated efficient purification of CH4 in solvents such as water, MeOH, and various others. For H-2 purification, Os-1/PTA SACs demonstrated excellent performance in gas, water, and MeOH. Notably, in water and MeOH, it selectively removed CO without consuming H-2 with low free energy barriers. The strong Os-PTA interactions and charge transfer mechanism contributed to its exceptional catalytic activity. Our findings shed light on SAC behavior and their potential for efficient CH4 and H-2 purification. By addressing impurity challenges and improving clean energy utilization, these findings contribute to the development of sustainable energy technologies.