Exploring the photocatalytic total oxidation of methane through the lens of a prospective LCA

Abstract

Hundreds of megatons of the second most important greenhouse gas (GHG), methane, are released annually to the atmosphere, often from emission sources which are difficult to abate. Research on post-emission mitigation technology is scarce and still in its infancy. This paper proposes a self-sufficient photocatalytic system to mitigate atmospheric methane via total oxidation to CO2 and analyzes its future viability and feasibility using environmental as well as physicochemical metrics. A four-step, explorative, scaled-up, prospective life cycle assessment (LCA) for the year 2050 shows that, in the best-case scenario, the market-ready photocatalytic module will amortize the produced GHG emissions in 1.5 years, while under more conservative assumptions, the physicochemical properties hinder a climate reasonable implementation. Targets like photocatalytic turnover numbers as well as reaction rates are calculated and compared to values reported in the literature to enable goal-oriented research and development. It is shown that more R&D is needed to have the proposed photocatalyst ready by 2050. The importance of methane mitigation development is highlighted and avenues for doing so are presented.