Three-dimensional MOFs confined Anderson-type POMs clusters—Templated fabrication of porous Co-NiMo/Cr2O3 catalyst with superior NH3-SCR catalytic activity

Abstract

Fabricating ecofriendly and high-performance NOx reduction catalysts is significant but challenging. This study introduces an innovative approach for creating homogeneous and porous Co-NiMo/Cr2O3 composites by employing a POMs@MOFs (POMs = polyoxometalates, MOFs = metal organic frameworks) core − shell template as a precursor and subsequent high-temperature treatment, in which the Anderson-type POMs are confined within the MIL-101 MOFs as secondary building units. The well-organized architecture of NiMo6@MIL-101 made it possible to provide a widely dispersed metal source and later transform into defect-rich catalyst. This confinement strategy allows the prepared Co-NiMo/Cr2O3 catalysts to be uniformly dispersed without aggregation and exposes abundant active sites. It also triggers more electron transfer, producing a strong synergistic effect that results in an increase in specific surface area, Olatt/Otol ratio and the number of acidic sites. Boosted by synergistically multidoping effect, the as-prepared Co-NiMo/Cr2O3 catalyst exhibits superior activity in NOx reduction (95 %, 150 °C), which is 3 times that of Cr2O3 derived from pure MOFs under the same condition. This work may shed the light on the design and fabrication of multifunctional nanoporous metal oxide composites materials and inspire the application of polyoxometalates in NOx removal processes.