Entropy-Enhancing Strategy Enables Highly Efficient Pt Utilization for High-Temperature H2O–CO2 Coelectrolysis

Coelectrolysis of H₂O and CO₂ using high-temperature solid oxide cells offers a highly efficient solution for converting greenhouse gases into valuable fuels and chemicals. Although Pt is an effective catalyst for this reaction, its high cost has limited its usage. Herein, we present that Pt-containing alloy catalysts with increased entropy exhibit high Pt utilization efficiency, catalytic performance, and thermal stability. Ab initio molecular dynamics and density functional theory simulations predict that the entropy enhancement strategy can stabilize Pt and provide catalytic properties comparable to those of pure Pt metal, while substantially reducing the required amount of Pt. These 10-nm-sized alloy catalysts were synthesized in situ within the porous fuel electrode and supported on a gadolinia-doped ceria scaffold using an advanced infiltration technique. The employment of the catalyst enabled a distinct improvement in cell performance compared to the widely adopted electrode material, and the Pt usage can be successfully reduced by 80% with a similar performance to pure Pt. Moreover, this process was successfully scaled up to industrial-sized cells with an active area of 16 cm², resulting in a high coelectrolysis current density of 1.6 A/cm² at 1.5 V and 850 °C. Notably, the catalyst demonstrated stable operation for over 200 h at a high current density of 1 A/cm² and 850 °C with negligible deterioration, verifying its feasibility for practical applications.