Solution Combustion Synthesis of ZnO Using Binary Fuel (Glycine + Citric Acid)

Abstract

Solution combustion synthesis (SCS) of zinc oxide was performed using a binary fuel, glycine and citric acid. It was established that combustion occurs due to oxidation of zinc nitrate–glycine complexes. Citric acid acts as an inhibitor of SCS reaction. An increase in relative content of organic fuel in the solution leads to a reduction in maximal combustion temperature and to formation of elemental carbon (0.2–1.6 wt %) and organic fragments (1.55–3.29 wt %) in SCS-produced zinc oxide. Carbon impurity and organic fragments were removed by annealing at 600°С. The produced wurtzite-type ZnO crystals had a size of 27–37 nm and were assembled into agglomerates. After annealing at 500°С, the specific surface of the powder was 8.44–11.09 m²/g. The photocatalytic activity of ZnO powder was evaluated from the rate of hydroquinone photodecomposition in solution.