Ecofriendly Sunlight-Mediated Nontoxic Bimetallic Nanoparticles: Synthesis, Reusable Catalytic Membrane, and Biosensor Applications.

Bimetallic nanoparticles (BMNPs) combine the desirable properties of two distinct metals that outperform conventional monometallic nanoparticles (NPs). This work presents a novel ecofriendly silver-copper (Ag-Cu) BMNPs synthesis using sunlight as a green reducing agent, enableing rapid Ag-Cu BMNPs formation at room temperature within 10 min. This method exploiting the facile reduction of Ag⁺ to Ag⁰, which subsequently mediates the reduction of Cu⁺ to Cu⁰ via water radiolysis-generated species. The Ag-Cu BMNPs were integrated into two reusable catalytic membranes: PTFE@Ag-Cu, formed by immobilizing Ag-Cu BMNPs onto a polytetrafluoroethylene (PTFE) syringe filter, and ACF@Ag-Cu, synthesized via in-situ growth of Ag-Cu BMNPs on activated carbon fiber (ACF) cloth. PTFE@Ag-Cu displays exceptional performance and reusability, converting 2100 mL of 0.15 mM p-nitrophenol to p-aminophenol over 105 cycles at a flow rate of 20 mL min. The Ag-Cu BMNPs also exhibit peroxidase-mimic activity, enabling colorimetric HO detection with a range of 0-200 mM and a limit of detection (LOD) of 13.3 µM in solution. Further, the Ag-Cu nanoenzyme demonstrates strong potential for electrochemical glucose detection, achieving an LOD of 0.1 µM and sensitivity of 5221 µA × 10 m⁻ cm⁻.