Visible-light driven photocatalytic degradation of pirimicarb by pt-doped agins₂ nanoparticles

This study describes the synthesis and characterization of Pt-doped AgInS₂ nanoparticles and reports their prospective application as visible-light catalysts for photodegradation of frequently used pirimicarb insecticides, which pose serious health and environmental concerns. The nanomaterials were characterized by XRD, SEM, TEM, XPS, photoluminescence (PL), and UV–vis diffuse reflectance spectra (DRS). The presented photocatalytic method for water treatment from pirimicarb has the advantages of using visible light source without any costly additive such as H₂O₂ needed in other employed methods. The Pt-doped AgInS₂ exhibited higher photocatalytic activities for pirimicarb degradation than undoped AgInS₂. The 1.0 wt% Pt/AgInS₂ photocatalyst exhibited the highest photodegradation rate, showing enhancement of 56% in comparison to the pure AgInS₂ photocatalyst. The photodegradation rate was found to increase with increasing the catalyst dosage until reaching the optimal dosage of 1.0 g L⁻¹. The pirimicarb degradation was significantly more efficient under acidic conditions, and the rates drastically dropped upon increasing the pH. The photocatalytic mechanism of Pt/AgInS₂ composites and the main active species involved in the process were investigated. The mechanism of pirimicarb degradation was proposed via two different pathways, N-dealkylation and decarbamoylation. Lastly, the photocatalysts demonstrated remarkable stability and were reusable in three successive catalytic tests without compromising catalytic activities. The Pt/AgInS₂ photocatalyst also exhibited efficiency and feasibility in pirimicarb removal from environmental lake and river water samples.