Methane Valorization Toward Carbon Neutralization: Catalytic Materials, Multiphase Interfaces, and Reactor Engineering Under Mild Conditions

Abstract

The direct conversion of methane into value-added chemicals under mild conditions offers a sustainable pathway to utilize this abundant hydrocarbon feedstock and mitigate greenhouse gas emissions. However, the thermodynamic stability of the C─H bond and the propensity for product overoxidation pose formidable scientific challenges. This review systematically summarizes recent breakthroughs in electrocatalytic, photocatalytic, and photoelectrocatalytic strategies for methane valorization. We critically examine fundamental activation mechanisms, structure-property relationships in catalyst design, and strategies to tune product selectivity toward liquid oxygenates and coupled hydrocarbons. Beyond material innovation, this review places particular emphasis on reactor engineering, elaborating on the evolution from conventional batch systems to advanced continuous flow architectures, such as gas convection electrodes and hierarchical triphase diffusion architectures, to overcome mass transfer limitations. Finally, we provide forward looking perspectives on emerging frontiers, including data-driven catalyst discovery and integrated system design, to guide the transition from laboratory research to industrial implementation.