Synthesis of surfactant assisted Cu2ZnSnS4 (CZTS) photocatalysts for removal of dyes from wastewater

Abstract

Herein, pure and hexamethylenetetramine (HMT) assisted Cu2ZnSnS4 were synthesized via effective hydrothermal method. The pure and HMT assisted Cu2ZnSnS4 samples were characterized to identify physicochemical behavior of photocatalysts. Prepared pure, 0.2 M, 0.4 M HMT assisted Cu2ZnSnS4 photocatalysts showed narrow band gap of 1.88, 1.47 and 1.23 eV. The HMT addition helped to reduce the photocatalyst’s band gap. The pure Cu2ZnSnS4 sample showed nanoparticles with higher agglomeration and improper growth. The 0.2 M HMT–Cu2ZnSnS4 samples showed smaller sized nanoparticles with little agglomeration on the surface of the nanoparticles. 0.4 M HMT-Cu2ZnSnS4 sample exhibited nanosheets like structure. The nanosheets were arranged in the interplanar manner. The obtained material was investigated to eliminate the RhB dye under visible light. The 0.4 M HMT-Cu2ZnSnS4 samples achieved higher efficiency of 84 %. The rate constant values of pure, 0.2 M, 0.4 M HMT-Cu2ZnSnS4 was 0.006, 0.009, 0.012 and 0.014 min−1. The active species corresponding to Cu2ZnSnS4 was holes which were confirmed by scavenger test. The good efficiency and rate constant values was attained by narrow band gap, electron hole transfer and better morphology which were attributed to the inclusion of HMT surfactant. 0.4 M HMT-Cu2ZnSnS4 will be prospective material for futuristic environmental remediation.