A samarium tellurate dispersion in a graphene matrix: Interfacial engineering of a functional nanocomposite for the enhanced electrochemical sensing of clothianidin

The impact of nanoparticle's dispersion within a specified matrix governs the functionality of the resulting nanocomposite; however, the interfacial properties between the nanoparticles and matrix components can also play a role but have not been sufficiently emphasized. Therefore, we explored a fully functional interface between samarium tellurate (STO) and laser-induced graphene (LIG) utilizing a method that effectively dispersed STO within the LIG matrix via interfacial engineering. This STO–LIG nanocomposite was applied to enhance the electrochemical detection of clothianidin (CLN), which is a neonicotinoid often used in pest control with persistent adverse effects on non-target organisms and pollinators. However, previous nanocomposite-modified electrodes for detecting CLN did not meet practical requirements and were not evaluated for monitoring soil. In the designed nanocomposite, STO provided highly selective adsorptive sites for CLN adsorption, while LIG offered robust electronic conductivity. To optimize the activity, the composite interfaces were engineered using a bottom-up assembly strategy with a precipitation-cum-deposition method. Comprehensive assessments revealed that STO was effectively dispersed through the gradual chemisorption of STO onto LIG via the C–O–Te(Sm) bond, a newly discovered active site. Owing to this remarkable active site, the STO–LIG nanocomposite exhibited high sensitivity (1.33 μA μM⁻¹ cm⁻²) and selectivity (>95 %) in detecting CLN in soil and water samples. Overall, this study provides insights into the design and formation of a nanocomposite with an effective interface and good charge transfer characteristics.