Low-temperature CO preferential oxidation in H₂-rich stream over Indium modified Pd-Cu/Al₂O₃ catalyst

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Preferential oxidation of carbon monoxide (CO-PROX) is crucial for purifying hydrogen (H$_{2}$) in fuel cells.
• Low-temperature CO-PROX requires highly active and selective catalysts.

Purpose of the Study:

• To investigate the effect of Indium (In) doping on the catalytic performance of Pd-Cu/Al$_{2}$O$_{3}$ for low-temperature CO-PROX.
• To understand the role of In in enhancing the CO-PROX reaction mechanism.

Main Methods:

• Synthesis of Pd-Cu/Al$_{2}$O$_{3}$ catalysts with extremely low palladium (Pd) loading (0.06 wt%) using co-impregnation.
• Systematic characterization of catalyst properties and performance evaluation at 30 °C.

Main Results:

• Pd-Cu-In$_{0.25}$/Al$_{2}$O$_{3}$ achieved 40% CO conversion and 100% CO$_{2}$ selectivity for over 120 min at 30 °C.
• Indium doping promoted the dispersion of copper species and facilitated the re-oxidation of Pd and Cu.
• The modified catalyst demonstrated significantly superior performance compared to undoped Pd-Cu/Al$_{2}$O$_{3}$.

Conclusions:

• Indium doping effectively enhances the catalytic activity and stability of Pd-Cu/Al$_{2}$O$_{3}$ for low-temperature CO-PROX.
• The improved performance is attributed to the formation of In$_{2}$O$_{3}$, enhanced Pd/Cu dispersion, and facilitated redox cycling.
• This study offers a promising strategy for developing efficient catalysts for hydrogen purification.