Unlocking the potential of in-situ thermally reduced graphene oxide anchored with ternary metal oxide-spinel catalyst for sustainable high-performance electrochemical valorisation of CO2

[Display omitted] •Developed TMO-1@rGO catalyst for efficient CO2 reduction to formate.•Achieved 97.4 % faradaic efficiency with high current density (−21.92 mA/cm2).•Catalyst retains 94% stability after 3 h of continuous operation.•Synergistic TMO-rGO structure enhances activity and selectivity.•Eco-friendly, scalable approach aids transition to carbon–neutral economy. Increasing energy consumption and dependence on fossil fuels will release 500 megatons of CO2, worsening global warming. Scientists are tackling this problem by converting CO2 into valuable chemicals. This work presents in-situ grown ternary metal oxide (TMO) nanocomposite grafted reduced graphene oxide (rGO) catalysts for electrochemical reduction of CO2 to produce value-added products. TMO was synthesized using a solution combustion process to produce thermally reduced graphene oxide with ternary metal oxides (CuO, Co3O4, and NiO). The characterization of the catalysts by various techniques such as XRD, FT-IR, Raman, FE-SEM, EDAX, TEM, XPS, and TG analysis confirmed the incorporation of TMO into rGO with an average crystallite diameter of 32 nm having controlled morphology, high purity, and scalability. The performance of the catalyst was evaluated using CV, LSV, CA, EIS, ECSA, and Tafel slope analysis which achieved a high current density of −21.92 mA/cm2 at −1.30 V versus RHE in a CO2-saturated electrolyte and outperformed monometallic oxide catalysts and rGO alone. The catalyst exhibited low charge transfer resistance (712 Ω) and a Tafel slope of 56.6 mV/dec, demonstrating efficient reduction of CO2 with a Faraday efficiency of 97.4 % in the production of formic acid. The catalyst showed remarkable stability, maintaining 94 % of the initial current density during a 3-hour chronoamperometry test. Furthermore, long-term stability tests of 6 and 9 h were performed for the catalyst design. The proposed formic acid formation mechanism highlights the synergistic effect of ternary metal oxide spinel and rGO support. This environmentally friendly approach to CO2 reduction supports a sustainable path towards a decarbonized society.