A series of solid solutions of composition Zn_xCo_3-xO₄ with 0 ≤x ≤ 1, crystallising in spinel structure have been characterised by measurements of unit cell parameter, electrical conductivity and magnetic susceptibility. The results have been rationalised on the basis of cation distribution. A comparison with the solid solutions of composition Ni_xCo_3-xO₄ is also made.

With the aim of finding a suitable electrocatalyst for the efficient reduction of carbon dioxide, the electrochemistry of nickel (II) complex of 1,3,6,9,11,14-hexaazatricyclo [12·2·1·1] octadecane was studied using cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) techniques in the presence and absence of CO₂ in 100% H₂O, CH₃CN-H₂O mixtures (20–100%) and DMF-H₂O (70–100%) mixtures. The efficiency of this process is determined using the coulometry technique. CO is the major product in the gaseous phase and HCOOH the sole product formed in the solution phase.