The electrochemical CO2 reduction reaction (ECO2RR) offers an attractive strategy to convert CO2 into valuable chemicals and fuels by using renewable electricity. However, this approach suffers from a large energy barrier for CO2 activation, intricate reaction pathways, and competitive hydrogen evolution reaction, leading to poor activity and selectivity. This thesis aims to develop effective strategies for adjusting the local electrical densities of carbon frameworks and designing carbon-based electrocatalysts for ECO2RR with superior performance. A nitrogen (N) and boron (B) dual-heteroatom co-doping strategy was first proposed for porous carbon structures to enhance their activity and selectivity. A versatile salt-sugar method was developed to synthesise N- and B- doped 3D hierarchical porous carbon with a large surface area and high doping levels. This metal-free carbon-based catalyst had high activity at low potential and good selectivity through a CO2-to-CO route, which was attributed to a synergistic effect between doped N and B atoms. Then, a microwave-induced-plasma assisted rapid synthesis route was proposed to atomically disperse non-precious Ni atoms into N-doped graphene networks and form an unsaturated Ni-pyridinic N2 local coordination environment with superior ECO2RR activity and selectivity towards CO. Furthermore, a secondary heteroatom, S, was introduced into the unsaturated Ni-N2 structure to form a N and S dual-heteroatom anchored Ni single-atom catalyst. A coordinated structure evolution was observed, and S vacancies were generated at a high voltage. Both doped S atoms and evolutionary S vacancies in the Ni-N2 coordination environment can facilitate CO2 conversion to CO. Finally, a natural molecule vitamin B12 was investigated as an active molecule to modify the inactive reduced graphene oxide by π-π stacking on the surface. This hybrid system presented high CO Faradaic efficiencies, CO partial current densities, and TOFs, indicating superior ECO2RR activity from molecule vitB12. The results from this thesis demonstrate that heteroatom doping, atomically dispersing transition metal, and hybridization with active molecules are efficient strategies to design carbon-based electrocatalysts. These highly efficient catalytic systems can potentially be utilised in the future for industrial-scale ECO2RR, for example, in an anion exchange membrane-based membrane electrode assembly for flow cell devices.