Boosting piezocatalytic performance of Ag decorated ZnO by piezo-electrochemical synergistic coupling strategy

The highly efficient piezocatalysts of Ag decorated ZnO nanocrystals (Ag-ZnO) have been designed and synthesized. Remarkably, piezocatalytic activity of Ag-ZnO depends on Ag concentrations. The piezocatalyst with suitable amount of 15% Ag-ZnO presents excellent piezocatalytic activity towards methylene orange (MO) organic dye degradation under ultrasonic vibration. The reaction rate constant of 15% Ag-ZnO is up to 19.58 × 10 −3  min −1 , which is 4.2 times in contrast with pure ZnO. Piezocatalytic efficiency of 15% Ag-ZnO reaches to ~ 90.5% after 120 min via combining piezoelectric effect with electrochemical synergistic coupling strategy. It also demonstrates that Ag decorated and piezo-electrochemical synergistic coupling effects can induce large amount polarization electric charges to form active superoxide radicals (·O 2 − ) and hydroxyl radical (·OH), further greatly facilitate the carriers transport and accelerate the electric charges carrier separation of the reaction kinetics process resulting in promoting the piezocatalytic degradation activity. Furthermore, a novel piezocatalytic mechanism has been put forward to elucidate the relationship between piezocatalytic decomposition performance and contribution in Ag decorated, and piezo-electrochemical synergistic coupling effects. The promising strategy provides an innovative guidance and idea for designing excellent performance piezocatalyst in dye wastewater decolorization treatment application.