Synthesis of TiNi by a green method

Abstract

A green method for the synthesis of titanium–nickel (TiNi) using Penicillium sp. fungus as a bioreactor and its comparison with the titanium–nickel synthesis produced by l-cysteine as a reducing agent are reported. In this work, the authors show that Penicillium sp. in contact with titanium (Ti) and nickel (Ni) salt solutions produces a nanocomposite material: titanium–nickel/titanium dioxide (TiO2). The experimental procedure was carried out at room temperature. The concentrations of the solutions used for both metal ions were 2·54 × 10−4 M. The analysis by ultraviolet–visible showed the characteristic bandgap absorption for titanium dioxide at 250 nm, and the X-ray powder diffraction analysis showed the phase reflections of titanium–nickel alloy and titanium dioxide. In order to propose a route for the biosynthesis using the fungus, titanium–nickel was synthesised using l-cysteine as a reducing agent at 25°C. Analysis by field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy shows agglomerates of nanosized particles corresponding to nickel and titanium metals. The use of l-cysteine and heat treatment at 250°C after the contact between l-cysteine and the ion salts in aqueous solution allow the easy synthesis of titanium–nickel. These processes represent new routes for the synthesis of titanium–nickel alloy under a non-exhaustive reaction.