Hierarchically ordered porous Ni-based cathode-supported solid oxide electrolysis cells for stable CO₂ electrolysis without safe gas

This study reported a hierarchically ordered porous Ni-based cathode of a solid oxide electrolysis cell to realise stable CO₂ electrolysis without the need of safe gas. The Ni/(Y₂O₃)_0.08(ZrO₂)_0.92 (YSZ) cathode support has a microchannel structure, which enabled efficient catalyst delivery to the reaction zone between the cathode and the electrolyte and resulted in facilitated gas diffusion through straight channels instead of the tortuous pores intrinsic to conventional porous electrodes. A catalyst network covering a Ni/YSZ scaffold reduced electrode polarisation resistance, prevented carbon formation and suppressed Ni oxidation. The facilitated gas diffusion diminished or eliminated concentration polarisation and carbon formation due to CO accumulation in the reaction zone. The novel hierarchical structure enables stable CO₂ electrolysis over conventional Ni-based cathodes with low capital and operational costs.