Synergistic Ag-Cu nanoparticles in MOF-derived carbon: Enhanced electrocatalytic sensing platform for nitrite detection

Accurate detection of nitrite plays a vital role in public health because excessive intake poses serious health risks. Metal-organic frameworks (MOFs) and their derivatives have emerged as a promising platforms for nitrite detection due to their adjustable structures and functionalization capabilities. In this study, we synthesized Ag/Cu-BTC by doping silver ions during Cu-BTC synthesis, followed by high-temperature carbonization to produce carbon-supported Ag-Cu bimetallic nanoparticles (Ag/Cu@C) for effective nitrite sensing. The carbon framework from MOF precursors not only enhances electrical conductivity and stability but also prevents nanoparticle aggregation. Silver addition enhances electron transfer efficiency and alters the electronic structure through synergistic interactions with copper, resulting in increased catalytic activity. The optimized Ag/Cu@C composite shows excellent sensing performance with a detection limit of 50 nM, high sensitivity (855.32 μA mM −1 cm −2 ), and a wide linear response range (0.2–10,000 μM). The sensor maintains 98.5–103.2 % recovery against 10-fold concentrations of common interferents (Cl - , NO 3 - , SO 4 2- , glucose), and retains 92.3 % initial current after 28 days, demonstrating exceptional selectivity and operational stability. These features highlight its significant potential for practical applications in environmental monitoring and food safety testing.