Constructing surface active centres using Pd–Fe–O on zeolite for CO oxidation

Newly active centres for CO oxidation using Pd–M–O (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, and Zr) on zeolite have been constructed. The derived co-impregnated Pd–Fe–Ox/NaZSM-5 catalyst not only showed high catalytic activity for low temperature CO oxidation, but was also a good kind of electrocatalyst for CO electrochemical stripping. It was probably because that the active centres including special oxygen species exhibit the high activity for CO oxidation. The typical 50% and 100% conversion temperatures of the co-impregnated Pd–Fe–Ox/NaZSM-5 catalyst for low temperature CO oxidation (T50 and T100) were 29.1 and 47 °C, respectively. XRD and XPS characterizations indicated that the addition of Fe increased the dispersion of the active Pd species and Pd species were easy to enrich on the surface of the catalyst. A functional interface, bimetallic catalytic active centre, was formed on the surface of the catalyst, which contained a certain quantity of special oxygen species. The direct proofs of the existence of this kind of active oxygen species were given by our H2-TPR and O2-TPD experiments.

Graphical abstractArtificial designed surface active centres using Pd–M–O (M = transition metal) on zeolite, including special Pd chemical environments and “weakly” chemical-adsorbed oxygen, not only showed excellent performance for CO oxidation at low temperature but was also successfully applied to CO electro-oxidation. Figure optionsDownload full-size imageDownload as PowerPoint slide