Executive Summary : | Double perovskite (DP) structures, with a general formula of AA′B2O6 and A2BB′O6, have gained attention due to their structural variety, stability, and potential applications. DP-based complexes are increasingly being explored for their potential in electrocatalytic and photocatalytic CO2 reduction (eCO2RR and pCO2RR), which are green technologies that utilize advanced catalytic materials and renewable energy sources. Despite the evolution of DP structures for magnetic and energy conversion-storage studies, few have been used in eCO2RR and pCO2RR. The research focuses on designing and synthesizing highly air-stable DP structures with broader applications. B-site substitution in DP structures can lead to interesting magnetic and electronic properties, while A-site substitution can result in long-range ordering to a spin-glass state. Transitional metal-based DP oxides exhibit band gap variation with oxygen stoichiometry, effectively absorbing UV or visible light, which could be promising for pCO2RR. The research also investigates 3d-4d and 3d-5d-based DP oxides, such as Ca2MnRuO6, sr2 MOsO6, for promising spintronic and magnetic complexes. The concurrent substitutions in DP structures, along with dn-electronic configuration and flexible valence state, can be beneficial for boosting electro and photochemical CO2 performances. |