Recent Advances in Periodic Temperature Operation of Heterogeneous Catalytic Microreactors

Periodic temperature operation (PTO) represents a cutting-edge approach to process intensification, employing rapid local heating through the integration of innovative materials and microreactors. This method can achieve substantial temperature swings of several hundred °C within microseconds to milliseconds. The benefits of PTO are manifold, including enhanced reaction rates, improved selectivity, in situ catalyst regeneration, decarbonization (negative carbon emission by utilization of renewable electricity), and energy conservation across a spectrum of reactions such as CO oxidation, methane pyrolysis, methane coupling, ammonia synthesis/decomposition, plastic depolymerization, steam/dry methane reforming and CO2 hydrogenation etc. This review initially examines studies on periodic concentration operation (PCO) to demonstrate dynamic surface coverages leading to higher reaction rates on the catalyst surface, a fundamental principle shared by PTO. This review then encapsulates the current state-of-the-art in PTO microreactor design and operation, delving into the historical development of PTO microreactors designed for periodic temperature modulation and highlighting pivotal technological advancements and groundbreaking findings. The review concludes with an exploration of potential reaction systems, future research trajectories and hurdles, and the implications of these developments.