Efficient piezo-catalytic dye degradation using piezoelectric 6H-SiC under harsh conditions

The development of novel piezoelectric catalysts against harsh conditions is indeed crucial for improving the piezo-catalytic degradation efficiency of colored organic dyes in wastewater. In this work, 6H-SiC nanoparticles (NPs) are utilized to piezo-catalytic degrade rhodamine B (RhB) and methylene blue (MB) under ultrasonic vibration for the first time. The degradation efficiency of RhB and MB reaches 98.8% and 98.7% within 80 min. The piezoelectricity of 6H-SiC is comprehensively analyzed by the piezoresponse force microscope (PFM) and finite element method (FEM). The strong oxidizing active free radicals generated by the continuous piezoelectric polarized electric field of 6H-SiC, i.e., •O₂⁻ and •OH, induce the decomposition reactions of colored organic dyes in solution. And the dyes are proven to degrade to harmless or less-harmful products gradually during the piezo-catalysis process by high-performance liquid chromatography tandem mass spectrometry (HPLC–MS). Moreover, RhB is also decomposed efficiently by 6H-SiC NPs under acidic and alkaline conditions. These results prove the feasibility of 6H-SiC for decomposing common water pollutants under harsh conditions and provide a new perspective for water purification.