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

High-rate production of syngas with tunable H-2/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-delta(LSFNi) cathode is used to trigger the in-situ exsolution of Ni-Fe alloy nanoparticles with an average size of similar to 45 nm uniformly distributed and socketed on LSFNi backbone, enabling efficient co-electrolysis of H2O and CO2 to H-2 and CO. At 1.5 V, the current density reaches similar to 1.0 A cm(-2) at 750 degrees C and similar to 2.4 A cm(-2) at 850 degrees C with near 100% Faradaic Efficiency. We demonstrate the feasibility of tuning the output H-2/CO ratio by nearly two orders of magnitude (from similar to 0.1 to similar 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.

Automated summary

High-rate production of syngas with tunable H-2/CO ratio and coke-free operation is achieved in a solid-oxide electrolysis cell (SOEC). Pre-reduction of the cathode triggers the in-situ exsolution of Ni-Fe alloy nanoparticles, enabling efficient co-electrolysis for H2O and CO2. The output H-2/CO ratio can be adjusted by manipulating feed gas ratio, temperature, and current density, demonstrating stable operation for >100 h without carbon deposition. Anode/electrolyte interface deteriorates with high current density operation due to rapid oxygen evolution.