Hydrothermal synthesis of AgInS2@biochar nanocomposites for the photocatalysis and electrochemical sensing of glufosinate herbicides

Abstract

A straightforward hydrothermal synthetic technique was used for the fabrication of a ternary chalcopyrite stacked biochar with great photocatalytic and electrocatalytic performance toward the photodegradation of malachite green (MG) dye and electrochemical sensing of glufosinate herbicides in contaminated water. The physicochemical characterization of the AgInS₂@biochar nanocomposite analyzed using XRD, FTIR, TGA, SEM, TEM, BET, EIS, XPS, PL, and DR-UV spectroscopic techniques suggests that it is an electronically semiconducting composite matrix with an optical band gap of around 1.49 eV. Morphological studies demonstrated the formation of interlaced spherical nanospheres of AgInS₂ nanoparticles with sufficiently exposed surfaces for effective surface activities. These include the photodegradation of the malachite green (MG) dye and electrochemical sensing of the glufosinate herbicide. Photodegradation studies reveal that AgInS₂@biochar exhibits outstanding photocatalytic performance toward the photodegradation of malachite green (MG) from contaminated water, achieving a high removal efficiency of 97.4% within 70 min due to its high electron transfer efficiency. The degradation followed pseudo-first-order kinetics, with a high K₁ value of ca. 0.0433 min⁻¹. In addition, the presented voltammetric studies establish that AgInS₂@biochar is a favourable electrode material for elusive electrochemical sensing of the toxic herbicide glufosinate in aqueous solutions with a low detection limit of ca. 0.026 μM.