Mg-incorporated sorbent for efficient removal of trace CO from H₂ gas

Removal of trace CO impurities is an essential step in the utilization of Hydrogen as a clean energy source. While various solutions are currently employed to address this challenge, there is an urgent need to improve their efficiency. Here, we show that a bead-structured Mg, Cu, and Ce-based sorbent, Mg₁₃CuCeO_x, demonstrates superior removal capacity of trace CO from H₂ with high stability. The incorporation of Mg boosts sorption performance by enhancing the porous structure and Cu⁺ surface area. Remarkably, compared to existing pelletized sorbents, Mg₁₃CuCeO_x exhibits 15.5 to 50 times greater equilibrium capacity under pressures below 10 Pa CO and 31 times longer breakthrough time in removing 50 ppm CO in H₂. Energy-efficient oxidative regeneration using air at 120 °C allows its stable sorption performance over 20 cycles. Through in-situ DRIFTS analysis, we elucidate the reaction mechanism that Mg augments the surface OH groups, promoting the formation of bicarbonate and formate species. This study highlights the potential of MgCuCeO_x sorbents in advancing the hydrogen economy by effectively removing trace CO from H₂.