In Situ Evidence Unveiling the Debate of Mechanism for Piezo-Catalysis

Abstract

The mechanism of piezo-catalysis remains a subject of active debate, with multiple competing perspectives still under discussion. The most prominent mechanistic interpretations currently include, but are not limited to, energy band theory, screening charge effects, and displacement current derived from the nanogenerator principle. Regardless of the mechanistic framework adopted, robust characterization and solid experimental evidence are indispensable for mechanistic validation. Unlike previous reviews that primarily emphasized catalyst design, material engineering, and catalytic applications, this perspective focuses on mechanistic verification from the standpoint of advanced characterization, particularly in situ techniques. We systematically summarize how pressure-dependent UV–Vis absorption spectroscopy, Raman and photoluminescence spectroscopy, Kelvin probe force microscopy, HAADF-STEM, chronoamperometry, as well as in situ techniques such as EPR and FTIR spectroscopy provide direct evidence for distinguishing among the major mechanistic hypotheses by probing stress-induced electronic structure evolution, charge behavior, reactive species, and reaction intermediates. Furthermore, the strengths and limitations of current experimental approaches are critically discussed, the key challenges in resolving the mechanistic debate are identified, and future research directions toward establishing an evidence-based and universally accepted mechanistic framework for piezo-catalysis are comprehensively proposed.