Electrochemiluminescence and Photoinduced Electrochemiluminescence Probing of Energy Conversion Catalysis.

Electrochemiluminescence (ECL) and its photoinduced variant, photoinduced electrochemiluminescence (PECL), have progressed beyond analytical detection tools to emerge as powerful spatiotemporal probes for interfacial electrocatalysis and photoelectrochemical processes. By transducing local electron-transfer events, reactive intermediates, and charge-carrier dynamics into photon emission, ECL and PECL provide a distinctive electrochemical-optical platform that combines high sensitivity, negligible optical background, and precise spatiotemporal controllability. This review systematically surveys recent methodological advances and representative applications of ECL and PECL in energy conversion catalysis. ECL-based approaches are shown to enable visualization of catalytic heterogeneity, dynamic evolution, and structure-activity relationships across a wide range of catalytic materials. Particular emphasis is placed on mechanistic insights into key electrocatalytic reactions, including the oxygen reduction, oxygen evolution, and hydrogen evolution reactions, in which spatial and temporal resolved ECL signals elucidate reaction pathways, intermediate dynamics, and local microenvironmental variations. In parallel, PECL is discussed as a selective probe for photoinduced charge-carrier utilization, recombination, and interfacial kinetics in photocatalytic and photoelectrochemical systems. Finally, current challenges and future perspectives for advancing ECL- and PECL-based methodologies in energy-related catalysis are outlined.