Integrating hydrogen utilization in CO₂ electrolysis with reduced energy loss

Electrochemical carbon dioxide reduction reaction (CO2RR) using sustainable energy is promising but energy-intensive. The oxygen evolution reaction (OER) is particularly problematic, being kinetically sluggish and causing anodic carbon loss. This research couples CO2 electrolysis with the hydrogen oxidation reaction (HOR) in a single cell, using a Ni(OH)2/NiOOH mediator to suppress carbon loss and catalyst poisoning. High selectivity (up to 95.3%) and stability (>100 h) are achieved at voltages below 0.9 V (50 mA cm⁻²). By transferring OER to a water electrolyzer, total polarization loss and energy consumption are reduced up to 22% and 42%, respectively. This work demonstrates the potential of integrating CO2 electrolysis with the hydrogen economy for improved energy/cost effectiveness.

Xiaoyi Jiang, Le Ke, Kai Zhao, Xiaoyu Yan, Hongbo Wang, Xiaojuan Cao, Yuchen Liu, Lingjiao Li, Yifei Sun, Zhiping Wang, Dai Dang, Ning Yan