On the Remarkable Performance of Silver-based Alloy Nanoparticles in 4-Nitrophenol Catalytic Reduction

Elimination of nitro groups from the toxic aromatic nitro compounds is of great environmental importance. A catalytic study of the 4-nitrophenol reduction on the surface of metallic and alloy nanoparticles is presented. The silver-based catalysts, with low amounts of platinum (10 % Pt), exhibit excellent catalytic activity without an induction-time, which fulfills both the performance and cost requirements for the catalytic reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH₄. The apparent rate constant of 59×10⁻³ s⁻¹ and an extremely high activity parameter value of 13,600 s⁻¹ g⁻¹ are reported for the first time. This mechanistic study suggests that hydrides are the active species for 4-nitrophenol reduction, and that the composition of the alloy can affect the reactivity and competition with the hydrogen evolution reaction. Our work opens future possibilities for the optimal design of efficient and low-cost catalysts for redox processes and neutralization of organic pollutants.