Bimetallic AgCu nanoparticles decorated on zeolitic imidazolate framework derived carbon: An extraordinarily active and recyclable nanocomposite catalyst for reduction of nitroarenes and degradation of organic dyes

Abstract

Zeolitic imidazolate framework-8 (ZIF-8) derived carbon (CZ-8) is explored as support to immobilize bimetallic AgCu nanoparticles (NPs) (denoted as AgCu@CZ-8) for the first time to be used as catalyst for reduction of nitroarenes and degradation of toxic dyes. A series of AgCu@CZ-8 with different Ag/Cu ratios is prepared by simultaneous chemical reduction of silver and copper nitrates in the presence of two reducing agents, i.e., NaBH4 and NH3BH3. Due to high surface area, presence of N atoms in the framework, modified electronic structure of AgCu caused by alloy formation and synergistic effects, the catalytic activities of bimetallic AgCu@CZ-8 nanocomposites are much higher than monometallic counterparts Ag@CZ-8 and Cu@CZ-8 for reduction of 4-nitrophenol (4-NP), and degradation of methyl orange (MO) and rhodamine B (RhB). Ag6Cu4 @CZ-8 exhibits a superb reaction rate of 12.93 min-1 and outstanding activity of 581880 min-1gcat-1 for reduction of 4-NP to 4-aminophenol (4-AP). On the other hand, Ag2Cu8 @CZ-8 delivers outstanding rate constants of 12.9 and 20.73 min-1 for degradations of MO and RhB, respectively. The catalyst shows excellent stability and recyclability after reuse for 5 cycles. The results presented here demonstrate that the carbonized ZIF-8 can provide a unique platform for the growth of uniformly dispersed bimetallic NPs with high catalytic activity towards various catalytic reactions.