SnS2 decorated biochar: a robust platform for the photocatalytic degradation and electrochemical sensing of pollutants

Abstract

Carbonization of waste material into functional carbonaceous material is a benign way of utilizing biomass. Herein, we report the decoration of SnS₂ nanoparticles on the biochar carbonaceous material using a facile hydrothermal synthetic strategy. The biomass collected from staminate flowers was pyrolyzed to obtain a biochar material containing a hydrophilic surface that creates an efficient environment for the decoration of SnS₂ nanoparticles. The SnS₂ decoration was thoroughly investigated using state-of-the-art instrumentation techniques. The morphological investigations indicate the formation of flower-shaped SnS₂ nanoparticles with a sufficiently exposed surface for effective surface activities. These include the photodegradation of the methylene blue (MB) dye and electrochemical sensing of Pb²⁺ and Hg²⁺ ions. The SnS₂@BC composite exhibits superior photocatalytic activity for the degradation of MB. Almost 95% of MB is removed within 60 min of contact time by a collaborative effect of adsorption and sunlight-driven photocatalysis. The removal of MB followed pseudo-first-order kinetics with a high K₁ value of ca. 0.013 min⁻¹. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) traces of the SnS₂@BC modified glassy carbon electrode (GCE) show a decent electrochemical response with limits of detection of ca. 0.28 and 0.55 μM in the case of Pb²⁺ and Hg²⁺ respectively. Furthermore, the DFT studies were carried out on a simulated model material and the results were in line with the experimental data. This work provides an economical treatment method for the photodegradation and electrochemical sensing of toxic contaminants present in wastewater.