Synthesis of heterogeneous Ag-Cu bimetallic monolith with different mass ratios and their performances for catalysis and antibacterial activity

Abstract

Combination of two or more metallic particles along with high surface area and porous structure exhibits enhanced catalytic as well as antibacterial activity. Here, Ag-Cu bimetallic monoliths were synthesized by nanocasting method by strictly adjusting the molar ratio of Ag-Cu. This work is mainly focused on the effect of molar ratio (Ag:Cu) on surface area (14–110 m2/g) and porous size of bimetallic monoliths, which has great influence on enhancement of catalytic and antimicrobial activity. The catalytic activity of bimetallic Ag-Cu monoliths was evaluated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of excess NaBH4. The reaction rate follows pseudo-first order for reduction of 4-NP with a reduction efficacy of ∼95%. The effect of Ag:Cu molar ratio and reaction conditions on the rate of reaction were investigated. In comparison with novel monometallic silver monoliths, bimetallic Ag-Cu monoliths exhibit high catalytic performance on the reduction of 4-NP. These heterogeneous catalysts were effortlessly recovered and reused (up to 8 cycles) after completion of catalytic reaction. As bimetallic Ag-Cu particles are well-known for antibacterial activity, so bactericidal properties of synthesized monoliths are tested against E. coli and B. subtilis bacteria by minimum inhibitory concentration method (MIC). The calculated EC50 (half maximum effective concentration) after completion of incubation period, against E. coli and B. subtilis were 22.87 ± 0.015 and 23.33 ± 0.09 respectively using Ag/Cu-3 bimetallic monolith.