Highly Efficient Piezo-Catalysis of the Heat-Treated Cellulose Nanocrystal for Dye Decomposition Driven by Ultrasonic Vibration

Abstract

In this work, the cellulose nanocrystal (CNC) heat-treated in an air atmosphere at 300°C shows the enhanced piezo-catalytic performance in Rhodamine B (RhB) dye decomposition. With the application of 180 min vibration excitation, the piezo-catalytic decomposition ratio of the heat-treated CNC for RhB dye can reach ~96.65%, while that of the raw CNC is ~34.58%. The improvement of piezo-catalytic performance of the heat-treated CNC can be explained as the symmetry of CNC is destroyed due to the introduction of defects through heat treatment, resulting in the enhancement of surface polarization and piezoelectric effect caused by non-uniform strain. The free radical scavenger experiments confirm that the main active specie involved in piezo-catalysis of the heat-treated CNC is superoxide radical. Three recycling utilization results show that the decomposition ratio of RhB dye remains about 95% without significant loss, indicating that the heat-treated CNC shows the good stability and the high efficiency in piezo-catalysis. Defect introduction into CNC is an efficient method to obtain a marvelous piezo-catalytic performance, it is expected to show broad application prospects in the catalytic treatment of dye wastewater.

Keywords: Piezo-catalysis, Piezoelectric effect, Cellulose nanocrystal, Heat treatment, Dye decomposition