Metal–Organic Framework (MOF) Template Based Efficient Pt/ZrO2@C Catalysts for Selective Catalytic Reduction of H2 Below 90 °C

Graphical Carbon-coated catalysts : Octahedral Pt/ZrO 2 @C, prepared by direct carbonization of the precursor UiO-66-NH 2 (a zirconium-based metal–organic framework), exhibits improved catalytic activity for selective catalytic reduction with H 2 at ambient temperature, compared with that of other platinum-based catalysts with porous materials as supports (see figure). Selective catalytic reduction (SCR) of NO x with H 2 as a reductant is the most promising denitration technology at low temperature. Achieving the conversion of NO x into N 2 at ambient temperature not only prolongs the service life of the catalyst, but also provides more freedom for the arrangement of denitration units throughout the flue gas treatment equipment. However, the development of highly efficient, stable, and environmentally benign supported platinum-based catalysts for H 2 -SCR at ambient temperature is still a major challenge. Herein, a 0.5 wt % Pt/ZrO 2 @C catalyst, which was composed of carbon-coated octahedral ZrO 2 with highly dispersed Pt particles, was prepared by using a new stabilization strategy based on UiO-66-NH 2 (a zirconium metal–organic framework) as a template. The catalytic performance of this Pt/ZrO 2 @C in H 2 -SCR was tested and confirmed to achieve near 100 % NO x conversion at 90 °C. Also, 70 % N 2 selectivity of the catalyst was achieved. The morphology, structure, and porous properties of the as-synthesized nanocomposites were characterized by using data obtained from field-emission SEM, TEM, XRD, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and N 2 adsorption–desorption isotherms. The results show that residual carbon formed by pyrolysis treatment is coated on octahedral ZrO 2 , and effectively prevents the agglomeration of platinum particles on the surface.