An all-oxide electrolysis cells for syngas production with tunable H2/CO yield via co-electrolysis of H2O and CO2

Abstract High-rate production of syngas with tunable H2/CO and coke-free operation is achieved in a solid-oxide electrolysis cell (SOEC). Prior to operation, controlled pre-reduction of La0.7Sr0.3Fe0.9Ni0.1O3-δ(LSFNi) cathode is used to trigger the in-situ exsolution of Ni-Fe alloy nanoparticles with an average size of ~45 nm uniformly distributed and socketed on LSFNi backbone, enabling efficient co-electrolysis of H2O and CO2 to H2 and CO. At 1.5 V, the current density reaches ~1.0 A cm−2 at 750 °C and ~2.4 A cm −2 at 850 °C with near 100% Faradaic Efficiency. We demonstrate the feasibility of tuning the output H2/CO ratio by nearly two orders of magnitude (from ~0.1 to ~7) by manipulating H2O/CO2 ratio of feed gas, operating temperature, and current density. Stable operation for >100 h is obtained without evidence of carbon deposition, although high current density operation leads to observable deterioration of anode/electrolyte interface due to the rapid oxygen evolution.