A direct sulfation method for introducing the transition metal cation Co2+ into ZrO2 with little change in the Brønsted acid sites

Direct sulfation of Zr–Co hydroxides provides a significant advantage over traditional impregnation by conserving Brønsted acid sites for the introduction of a second active component and also for subsequent catalytic reactions. After Pd loading, sulfated Zr–Co exhibits excellent activity, selectivity, and durability for the selective catalytic reduction of NOx by methane. Using Co K-edge X-ray absorption spectroscopy, we provide the direct evidence of the entrance of Co into the lattice of cubic zirconia to form a substitutional solid solution.

Graphical abstractDirect sulfation of Zr–Co hydroxides provides significant advantage for holding Brönsted acid sites than traditional impregnation.Figure optionsDownload full-size imageDownload high-quality image (108 K)Download as PowerPoint slideResearch highlights► Direct sulfation method introduced Co2+ into ZrO2. ► Changed little in Brønsted acidic sites. ► Co forms isomorphous substitutional cubic zirconia. ► Pd greatly promotes the activity for the NOx reduction.