Cluster catalysts are rapidly growing into an important sub-field in heterogeneous catalysis, owing to their distinct geometric structure, neighboring metal sites, and unique electronic structure. Although the thermodynamics and kinetics of the formation of nanoparticles have been largely investigated, the precise synthesis of clusters in wet chemical methods still faces great challenges. In the study, a quenching strategy of asymmetric temperature in solution for the rapid generation of vacancy-defect rich clusters is reported. The quenching process can be used to synthesize multitudinous metal compound clusters, including metal oxides, fluorides, oxygen-sulfur compounds, and tungstate. For oxygen evolution reaction (OER), IrO₂ clusters with abundant oxygen vacancies were obtained and uniformly dispersed in the solution. Compared to commercial IrO₂, the prepared IrO₂ cluster can be directly loaded on carbon paper and used as binder-free electrodes, which exhibit higher OER activity and long-term operational stability in alkaline electrolytes. The quenching strategy provides a simple and efficient method for the synthesis of clusters, which has tremendous potential for industrial-scale preparation and application, especially can be further applied to flow electrochemical generators.