Green synthesis of Cu nanoparticles supported on straw-graphene composite for catalytic reduction of p-nitrophenol

Abstract

It is quite desired to develop an effective and cost-efficient non-noble metal catalyst for the reduction of nitrobenzene compounds. In this work, a novel and highly reactive Cu nanoparticles (CuNPs) embedded straw-graphene composite (Cu-SG) was synthesized via a facile and green one-pot hydrothermal route and then used for p-nitrophenol (PNP) reduction in the presence of NaBH4 from an aqueous medium. In comparison to the Cu-G (0.42 min−1), the Cu-SG with hierarchical pore structure and smaller CuNPs exhibited better catalytic property in PNP reduction, especially under the conditions of a mass ratio of straw-to-GO = 1 and Cu2+ ions dosage = 0.15 mmol (0.93 min−1). Interestingly, unlike Cl−, NO3− and SO42− ions, the coexisted HCO3− ions in solution could crucially accelerate the removal of PNP (1.62 min−1). This may be since HCO3− ions can both ionize and hydrolyze in water, enabling them to regulate and promote the adsorption of PNP to Cu-SG. Besides, the Cu-SG displayed good catalytic stability and can be reused for six consecutive cycles without obvious performance reduction. This study offers an insight into addressing both water pollution remediation and high-value utilization of agricultural solid waste.