Photocatalytic dehydrogenation of light alkanes to olefins: mechanistic principles and catalyst engineering

Abstract

The exponential growth in global exploitable shale gas reserves has created a strategic imperative to upgrade abundant light alkanes, specifically ethane and propane, into high-value olefins via sustainable pathways. Traditional thermal cracking and dehydrogenation processes are well established industrially. However, they are constrained by extreme energy consumption, severe coke formation, and a substantial carbon footprint. Photocatalytic dehydrogenation has emerged as a transformative alternative, leveraging solar energy to drive endothermic C–H bond activation under mild conditions, thereby overcoming the thermodynamic and kinetic bottlenecks inherent to thermal routes. This review provides a comprehensive overview of recent advances in the photocatalytic conversion of light alkanes to ethylene and propylene. Furthermore, it systematically elucidates the fundamental principles governing C–H activation, distinguishing between non-oxidative pathways and oxidative strategies utilizing O₂, CO₂, or H₂O as terminal electron acceptors to enhance reaction kinetics and modulate product selectivity. Particular emphasis is placed on catalyst engineering strategies, including defect modulation, active site design, and electronic state regulation. Finally, it concludes by highlighting current challenges regarding photon utilization efficiency and overall alkane conversion, offering perspectives on future material design to bridge the gap between laboratory breakthroughs and industrial implementation.