Ag nanoparticles decorated 2D/2D TiO2/g-C3N4 heterojunction for efficient removal of tetracycline hydrochloride: Synthesis, degradation pathways, and mechanism

Abstract

In this study, a surfactant-assisted self-assembly method was used to synthesize atomically thin TiO2 nanosheets and construct 2D/2D TiO2/g-C3N4 heterojunctions with strong interfacial coupling. The prepared binary composites were subsequently modified using Ag nanoparticles to obtain a unique 0D/2D/2D Ag/TiO2/g-C3N4 heterojunction. Ascribed to its unique structure, the ternary heterojunction exhibited outstanding photocatalytic performance and 85.1 % tetracycline hydrochloride (TC) was decomposed within 25 min. The degradation rate of as-prepared ternary heterojunction was much higher than TiO2, g-C3N4, and TiO2/g-C3N4. The photocatalytic performance under different operating conditions (anion, initial concentration) was also investigated. The outstanding photocatalytic performance of Ag/TiO2/g-C3N4 can be ascribed to its efficient solar-light utilization capacity and low photogenerated charge carrier recombination. Moreover, possible TC degradation pathways were proposed and toxicity prediction indicated that most TC intermediates were decreased during the photocatalytic process. Besides, the possible photocatalytic mechanism was proposed based on experimental data and work function calculations.