Low-concentration methane removal: what can we learn from high-concentration methane conversion?

Abstract

Methane (CH₄) is the world's second most potent greenhouse gas after carbon dioxide (CO₂). Removal of low concentrations of CH₄ from the environment by an advanced oxidation process (i.e., total oxidation to CO₂) powered by solar energy is attractive. However, studies of solar-driven methane oxidation have focused on the selective conversion of CH₄ to high-value chemicals, where methane usually occurs in high concentrations. In this paper, the related work of selective conversion of high-concentration CH₄ is introduced first, and the mechanism of selective conversion of CH₄ is discussed. The “bad” reaction (i.e., total oxidation to CO₂) reported in selective conversion of high concentration CH₄ is pointed out, hoping to guide the related work of removal of low concentration CH₄.