▎ 摘　　要

NOVELTY - A catalyst comprises nickel and palladium alloying nanoparticles as an active metal, polyethylene imine-functionalized graphene oxide as carrier, and sodium borohydride as reducing agent. The precursors of nickel and palladium active metal and the polyethylene imine-functionalized graphene oxide are derived. USE - Catalyst for reduction of aromatic nitro groups in synthesis of tryptophan intermediate. ADVANTAGE - The environmentally-friendly catalyst is operated easily with high reliability, excellent catalytic performance, and aromatic nitro compound conversion rate of 99.9%, is suitable for reduction of aromatic nitro group to aromatic amino group, and is used repeatedly with high efficiency, and recovered easily. DETAILED DESCRIPTION - A catalyst comprises nickel and palladium alloying nanoparticles as an active metal, polyethylene imine-functionalized graphene oxide as carrier, and sodium borohydride as reducing agent. The composite nanocatalyst is represented by formula: NixPd1-x.PEI-GNs. The precursors of nickel and palladium active metal and the polyethylene imine-functionalized graphene oxide are derived. An INDEPENDENT CLAIM is included for preparation of catalyst for reduction of aromatic nitro groups in synthesis of tryptophan intermediate, which involves (i) adding 5 mg polyvinylpyrrolidone surfactant and 5-20 mg polyethylene imine-functionalized graphene oxide to 5 ml water, and uniformly stirring, (ii) adding precursor salt of active metal nickel and palladium, stirring for 20 minutes, where the ratio of nickel and palladium is 0.11-9.0, the precursor salt of the active metal nickel is nickel chloride, nickel nitrate, or nickel sulfate, and the precursor salt of active metal palladium is potassium tetrachloropalladate or potassium hexachloropalladate, (iii) adding sodium borohydride reducing agent to the reaction solution, and uniformly stirring for 30 minutes, (iv) centrifuging the reaction solution, washing, and drying.