Deciphering the mechanistic insights of 4-nitrophenol reduction catalyzed by a 1D–2D Bi2S3 nanostructured catalyst

Abstract

Exploring the reaction mechanism and the role of a catalyst in the conversion of pollutants to value-added products is vital for sustainable development. Herein, a polyvinylpyrrolidone-assisted liquid-phase reflux strategy was utilized to synthesize anisotropic 1D–2D Bi₂S₃ nanostructures. The as-synthesized nanostructures were used as catalysts in batch experiments for 4-nitrophenol (4-NP) reduction and they exhibited an apparent rate constant (k_app), turnover frequency (TOF), and activation energy (E_a) of 0.441 min⁻¹, 1.543 h⁻¹ and 26.13 kJ mol⁻¹, respectively. Also, the effects of catalyst dosage, NaBH₄ amount, 4-NP concentration, solvents, pH, and common ions were evaluated. Isotope labeling and kinetic isotope effects (KIEs) confirm that water is the proton source in 4-NP reduction. Electrochemical studies revealed that the nanostructured 1D–2D Bi₂S₃ enables the dissociation of BH₄⁻ into active absorbed and adsorbed hydrogen () species and assists in the catalytic reduction of 4-NP. This study offers a new insight into designing an efficient nanostructured 1D–2D Bi₂S₃ catalyst for 4-nitrophenol reduction.