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

Abstract

Methane (CH₄) and hydrogen (H₂) show promise as low-carbon energy sources, but their impurities, including H₂ and CO, pose challenges for storage and use. To address these challenges, a robust purification protocol for CH₄ and/or H₂, 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. Os₁/PTA SACs exhibited superior catalytic activity, and the ease of oxidation follows the CO > H₂ > CH₄ order. It facilitated efficient purification of CH₄ in solvents such as water, MeOH, and various others. For H₂ purification, Os₁/PTA SACs demonstrated excellent performance in gas, water, and MeOH. Notably, in water and MeOH, it selectively removed CO without consuming H₂ 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 H₂ purification. By addressing impurity challenges and improving clean energy utilization, these findings contribute to the development of sustainable energy technologies.