Nanoporous Single‐Crystalline Oxide Catalysts for Preferential Oxidation of CO in H2 with an Ultra‐wide Temperature Window.

Preferential oxidation of CO in H2 (PROX) reaction is a promising solution to the on‐board purification of CO‐contaminated H2 fuel for use in next‐generation proton‐exchange membrane fuel cells (PEMFC). However, achieving high CO selectivity, activity and structural stability across the wide temperature window remains a great challenge. Herein, we fabricate centimeter scale interfacial PROX catalysts grown from nanoporous single‐crystalline Pr2O3 and Nd2O3 monoliths with lattice surface‐deposited Pt clusters at nanoscale. We demonstrate complete and selective removal of CO in H2 over an unprecedented wide temperature window (253–403 K). The monoliths are integrated with an operational PEMFC to purify the H2 fuel contaminated with CO (30 ppm) and enable stable power output for >400 h; over two thousand times longer than without. This work demonstrates that the nanoporous single‐crystalline oxide monoliths can simultaneously achieve the stability and overall performance required to realize practically useful PEMFCs. [ABSTRACT FROM AUTHOR]