Green fabrication of AuNPs/CMTKP/g-C3N4 nanocomposites with enhanced photocatalytic activity for the removal of nitric oxide under visible-light irradiation

A facile and green method of in-situ photo-reduction was developed to fabrication the AuNPs/CMTKP/g-C3N4 nanocomposites catalyst. Carboxymethyl tamarind kernel polysaccharide (CMTKP) was used to regulate and stabilize the monodispersed AuNPs onto g-C3N4 NSs surface. The morphology, microstructure and composition of the Au-CMTKP-g-C3N4 nanosheets hybrids were systematically characterized. The NO removal experiments showed that AuNPs/CMTKP/g-C3N4 nanocomposites exhibited excellent visible-light response and enhanced photo-oxidization ability to inhibit the generation of NO2. Compared with g-C3N4 NSs, the removal efficiency of 4 wt% Au-CMTKP-g-C3N4 NSs was increased by 27.5%. Reactive radicals during the photocatalysis processes were identified by electron spin resonance (ESR) study. As identified by ESR, center dot O-2(-), center dot OH and photogenerated holes could be considered as the main activated species involved in NO removal. The possible mechanism for photocatalytic NO oxidation was also proposed. Meanwhile, this photocatalyst also demonstrates suitable stability, showing good potential in practical applications. (C) 2020 Elsevier Ltd. All rights reserved.