Co₃O₄–CuCoO₂ Nanomesh: An Interface-Enhanced Substrate that Simultaneously Promotes CO Adsorption and O₂ Activation in H₂ Purification

Nanomaterials are widely used as redox-type reaction catalysts, while reactant adsorption and O 2 activation are hardly to be promoted simultaneously, restricting their applications in many important catalytic fields such as preferential CO oxidation (CO-PROX) in H 2 -rich stream. In this work, an interface-enhanced Co 3 O 4 –CuCoO 2 nanomesh was initially synthesized by a hydrothermal process using aluminum powder as a sacrificial agent. This nanomesh is systematically characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy, Raman spectroscopy, X-ray absorption near-edge spectroscopy, hydrogen temperature-programmed reduction, and oxygen temperature-programmed desorption. It is demonstrated that the nanomesh possesses high-density nanopores, enabling a large number of CO adsorption sites exposed to the surface. Meanwhile, electron transfer from O 2– to Co 3+ /Co 2+ and the weakened bonding strength of Co–O bond at surfaces promoted the oxygen activation and redox ability of Co 3 O 4 . When tested as a catalyst for CO-PROX, this nanomesh with an optimized pore structure and a surface electronic structure, exhibits a strikingly high catalytic oxidation activity at low temperatures as well as a broader operation temperature window (i.e., CO conversion >99.0%, 100–200 °C) in the CO selective oxidation reaction. The present finding should be highly useful in promoting the quest for better CO-PROX catalysts, a hot topic for proton exchange membrane fuel cells and automotive vehicles.