Direct Evidence of the Relationship between Piezoelectricity and Catalytic Activity

Abstract

Piezocatalysis is highly valued for its efficient energy conversion and environmental capabilities. However, the fundamental connection between piezoelectricity and piezocatalytic activity remains to be thoroughly investigated. Herein, piezoceramic thin flakes with varying levels of piezoelectricity were examined to quantitatively assess the impact of the piezoelectric coefficient (d33) on the piezocatalytic activation in energy and environment applications. The piezoceramic flake, 220 μm thick, possessing the highest piezoelectricity (d33 = 1100 pC/N), demonstrated the highest H2O2 yield (572 μM h-1) and the fastest degradation rate (k = 0.0725 min-1) of Rhodamine B (RhB), exceeding the best performance of previously reported ceramic blocks. In contrast, the same thickness flake with the lowest piezoelectricity (d33 = 150 pC/N) exhibited the weakest piezocatalytic performance. By analyzing internal carrier characteristics and simulating carrier migration pathways under an electric field, a quantitative relationship between piezoelectricity and piezocatalytic activity was established. The piezoceramic flake with higher piezoelectricity demonstrated a higher effective free carrier concentration, a larger number of transiently migrating carriers, and a shorter migration distance due to a stronger built-in electric field, resulting in enhanced piezocatalytic activity. This work clearly elucidates the relationship between piezoelectricity and piezocatalytic activity.

Keywords: piezoelectricity, piezocatalytic activity, piezoceramic flake