Accelerated Electron Transport and Improved Photocatalytic Activity of Ag/AgBr Under Visible Light Irradiation Based on Conductive Carbon Derived Biomass

Abstract

Ag/AgBr (PLAS) exhibits good photo-oxidative properties for organic pollutants degradation under visible light. However, poor separation of photogenerated charge carriers at the catalyst interface, caused by decelerated photoexcited electron migration results in lower photocatalytic activity and limits the practical application of PLAS. In this work, activated carbon (ACK) from microwave pyrolysis of chemical impregnated biochar (BCR) pinecone is employed as a conductive carbon support for coupling Ag/AgBr (PLAS–ACK) as synthesized through the thermal polyol route. The structural, electrochemical and optical properties of prepared composites are characterized by various techniques. ACK exhibited faster electron transfer compared to BCR and commercial activated carbon (CAC) from the Nyquist EIS plot, due to its abundant sp2 C and interconnected conductive carbon structures. The resulting PLAS–ACK exhibited an improved degradation efficiency of 92% on tetracycline (TC) antibiotic in a neutral solution after 180 min, which is better than PLAS–BCR and PLAS–CAC under visible LED light irradiation. The superior degradation efficiency of PLAS–ACK is ascribed to the accelerated transport of photo-excited electrons, enhancing the separation of photogenerated charge carriers upon introduction of conductive ACK. The reaction mechanism of PLAS–ACK on TC degradation based on a scavenging experiment was also proposed in this work. (a) Electrochemical impedance spectroscopy of different carbons for photo-excited electrons transport and (b) degradation performance of prepared composites on Tetracycline under visible LED light irradiation.