Single step synthesis of nano-sized NiO-Ce0.75Zr0.25O2 composite powders by glycine nitrate process

Abstract

Single step synthesis of NiO–Ce0.75Zr0.25O2 and Ce0.75Zr0.25O2 powders was successfully achieved by glycine nitrate process (GNP). In this method, a precursor solution is prepared by mixing glycine with an aqueous solution of mixed (Ni, Ce–Zr) metal nitrates in the requisite quantities. The precursor was heated to evaporate excess water, yielding a honey-like liquid. Further heating the precursor at above 200 °C caused the precursor liquid to auto-ignite. Cubic fluorite nature of Ce0.75Zr0.25O2 and NiO phases was identified by XRD for the as-prepared samples. SEM and TEM analysis illustrate the foamy microstructural nature and the particle sizes of range 35–50 nm and 12–18 nm with a BET surface area of 5.5 and 29.2 m2/g for NiO–Ce0.75Zr0.25O2 and Ce0.75Zr0.25O2 powders respectively. Catalytic performance for partial oxidation of methane of Ni–Ce0.75Zr0.25O2 showed 58% methane conversion for a time period of 12 h with good H2 and CO selectivity along with H2/CO ratio of 2.