Optimal design of powdered nanosized oxides of high surface area and porosity using a citric acid aided route, with special reference to ZnO

Polybasic hydroxy and amino carboxylic acid routes offer great advantages for the synthesis of powdered oxide nanomaterials of high surface area and porosity. A detailed analysis of the state-of-the-art in the field is performed, and some unresolved problems are discussed. Precursors of zinc oxide with the Zn2+:citric acid:ethylene glycol ratio of 1:1:0, 1:2:0, 1:4:0, 1:2:1, 1:2:2, 1:2:4 and 1:2:10 are studied. Their thermal decomposition is analyzed using DTA, IR, XRD, SEM, TEM methods, and porosity measurements in order to determine the component ratio and heating temperature enabling one to obtain the target oxide of the smallest particle size, the highest surface area, and the maximal amount of micropores. It is found that such a goal can be reached with the precursor of the 1:2:0 component ratio thermally treated at 400 °C.