Rational Design of Semiconductor Materials for Photocatalytic Conversion of Methane into Value-Added Chemicals.

Abstract

Photocatalytic methane conversion offers a promising, low-temperature pathway for upgrading this abundant yet highly inert hydrocarbon into value-added chemicals, circumventing the energy-intensive nature of conventional thermocatalytic processes. However, achieving high conversion efficiency and precise product selectivity remains a fundamental challenge. This review systematically summarizes recent advances in the rational design of semiconductor photocatalysts for methane valorization. We first outline the fundamentals of light-driven CH₄ activation and standardized protocols for performance evaluation. We then highlight advancements in material engineering, encompassing metal oxides, carbon nitride, and emerging organic frameworks, with a focus on establishing fundamental structure-activity relationships. Particular emphasis is devoted to structural and interfacial engineering strategies, including cocatalyst integration, morphological control, defect engineering, facet regulation, heterojunction construction, and elemental doping, which cooperatively modulate electronic structures and charge dynamics to enhance catalytic performance. Furthermore, we examine the critical interplay between catalyst architecture and the reaction microenvironment in steering the targeted product selectivity toward specific C₁ oxygenates (methanol, formaldehyde, formic acid) and C₂ products (ethanol, acetic acid, ethane, and ethylene). Finally, we discuss current bottlenecks and future opportunities, providing a strategic framework to guide the atomic-level design and practical optimization of next-generation photocatalytic methane utilization systems.