Nickel nanoparticles deposited into an activated porous carbon: synthesis, microstructure and magnetic properties

Activated carbons (AC) are commonly used as efficient adsorbents to remove contaminants. The incorporation of a magnetic material into the AC could greatly enhance its manipulation through magnetic separation. However, the composite material will need to have sufficiently saturated magnetization, and as low as possible coercivity to be easily attracted by commercial permanent magnets. In this letter we report on the correlation between microstructure and magnetic behaviour of Ni nanoparticles (NPs) embedded in an amorphous activated porous carbon (Ni-AC). The Ni-AC powders have been synthesized by means of an easy and low-cost procedure. The addition of sucrose during the preparation process provides effective protection in acid media. This Ni-AC composite has a microstructure composed of crystalline NPs with diameters in the range of 7-25 nm, and exhibits superparamagnetic behaviour at room temperature, with saturation magnetization values around 3 A m(2) kg(-1) under applied magnetic fields of 200 mT. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim