Reduction of 4-Nitrophenol Using Ficin Capped Gold Nanoclusters as Catalyst

Conversion of nitroarenes to aminoarenes has attracted great attention in pharmaceutical industry, agricultural production, environmental protection and chemical catalysis area. In this work, ficin capped gold nanoclusters(ficin@AuNCs) were prepared for the reduction of 4-nitrophenol to 4-aminophenol. The proposed catalyst was characterized by transmission electron microscopy, dynamic light scattering, fluorescence spectra and UV-Vis spectra. With NaBH₄ as the reducing agent, the reduction reaction could carry out completely within 10 min at 25℃. Interestingly, the resultant catalyst exhibited size-related properties in the reduction, smaller ficin@AuNCs exhibited higher catalytic activity. Its present pseudo-first-order rate constant was found to be 2.95×10^‒3 s^‒1 and the catalytic activation energy was 27.7 kJ/mol. Moreover, ficin@AuNCs-based catalyst displayed good stability, heading to 4-nitrophenol conversion of 98.5%-100.0% after six consecutive cycles. It has shown a great potential in construction of unique catalysts based on AuNCs for reduction reaction.