Harvesting Electricity from CO₂ Emission: Opportunities, Challenges and Future Prospects

The ever-increasing CO₂ emission has necessitated the search for suitable technologies for CO₂ utilization at a low cost. Recently, a novel concept called reactive gas electrosorption (RGE) for energy harvesting from CO₂ emission, which could boost the efficiency of a thermal power plant by 5% was proposed by Hamelers and coworkers. The concept involves mixing of air stream with a low CO₂ concentration with a stream of high CO₂ concentration in an alkaline aqueous electrolyte. However, this concept is faced with the challenges of designs specific for CO₂-electrolyte, and inadequate performance of the electrode materials. Therefore, this study showcases electricity generation opportunities from CO₂ via RGE and discussed challenges and prospect. The study reveals that the drawback relating to the electrode could be solved using heteroatom doped traditional carbon materials and composite carbon-based materials, which has been successfully used in capacitive cells designed for desalination. This modification helps to improve the hydrophilicity, thereby improving electrode wettability, and suppressing faradaic reaction and co-ion repulsion effect. This improvement could enhance the charge efficiency, sorption capacity durability of electrodes and reduce the energy loss in RGE. Moreover, intensification of the membrane capacitive deionization (MCDI) process to obtain variances like enhanced MCDI and Faradaic MCDI. Hybrid capacitive deionization (HCDI) is also a promising approach for improvement of the capacitive cell design in RGE. This intensification can improve the electrosorption capacity and minimize the negative effect of faradaic reaction. The use of alternative amine like Piperazine, which is less susceptible to degradation to boosting CO₂ dissolution is also suggested.