Rapid thermal synthesis of electrocatalysts: From thermodynamic equilibrium to kinetic trapping

Efficient electrocatalysts are pivotal for clean energy conversion, yet conventional near-equilibrium synthesis—limited by slow diffusion and thermodynamic relaxation—often yields structurally stable but catalytically constrained materials. This review defines rapid thermal synthesis (RTS) as a thermal-history-compressed, kinetically biased paradigm and establishes a practical framework to compare RTS with near-equilibrium routes across electrocatalyst systems. We summarize major RTS modalities (microwave heating, Joule heating/thermal shock, pulsed-laser-enabled synthesis, and magnetic induction heating) and benchmark them using unified thermal-shock descriptors (peak temperature, effective hot-time, and heating/cooling rates), together with reported structure/performance metrics where available and evidence-based proxies when quantitative descriptors are missing. Across diverse material families, RTS enables access to metastable phases and high-energy architectures that are difficult to obtain under equilibrium constraints. Mechanistically, compressed thermal histories can kinetically truncate relaxation pathways—suppressing Ostwald ripening, element segregation, and undesirable phase transitions—thereby stabilizing defect-rich, heterointerface-strengthened, and lattice-strained structures that enhance activity and selectivity in key electrochemical reactions. The central contribution of this review is thermodynamics–kinetics–structure coupling perspective that reframes RTS as “active-state regulation” rather than simply fast heating, and provides a transferable comparison rubric across methods and catalyst classes. Finally, we highlight translation barriers, including thermal/field non-uniformity, batch-to-batch reproducibility, time-resolution mismatch between ultrafast events and in situ probes, and scalability metrics (throughput and energy intensity), and outline actionable directions—trigger-synchronized operando diagnostics, process-window mapping, and Multiphysics/AI-assisted design—for intelligent, controllable ultrafast synthesis. Overall, RTS reshapes catalyst design beyond equilibrium constraints for sustainable energy technologies.