Electrochemical reduction of CO2 to syngas using carbon gels-green graphene composites as metal free electrocatalyst

The generation of syngas through the electro-reduction of CO 2 and the subsequent H 2 generation in a unified electro-conversion system emerges as a compelling strategy for the production of fuel precursors and chemicals. However, effective control of the CO:H 2 ratio is imperative to ensure the system's practical application. This necessitates the utilization of electrocatalysts that exhibit active sites favoring both CO 2 activation and regulated H 2 generation, along with characteristics such as high conductivity, an extensive active surface area, and economical and sustainable synthesis methodologies. In this study, carbon xerogel microspheres doped with eco-graphene, which was obtained by environmentally friendly methods, have been synthesized. It has been observed that the inclusion of eco-graphene provides a high graphitic character, as well as nitrogenous groups and quinones. These features not only improve the selectivity for CO production, but also decrease the overpotential in both CO 2 and water reduction reactions. The spherical morphology and porosity of the carbon xerogels have been shown to facilitate the accessibility of the reagents to the active sites, thereby enhancing the overall efficiency of the electrocatalysts. The optimal H 2 /CO ratio achieved in this study, ranging from 1 to 3, underscores the efficacy of the electrocatalysts in facilitating a single-vessel coupled Fischer-Tropsch synthesis. These electrocatalysts exhibit high selectivity for CO 2 electro-reduction, attaining a maximum efficiency of 89.2 %. • Eco-graphene was produced via a simple, eco-friendly synthesis method. • Xerogels with spherical morphology were synthesized via inverse emulsion method. • Eco-graphene offers high graphitic character with quinone and nitrogen groups. • Xerogels-graphene composites as metal-free catalysts efficiently converted CO 2 to syngas. • An optimal H 2 /CO ratio of 1:3 was achieved by adjusting eco-graphene content.