Abstract

A bulk porous CaZrO_3/MgO composite with plantinum nano-dispersion was synthesized in air atmosphere through the combination of several in situ reactions, including the pyrolysis of PtO_2. A mixture of CaMg(CO_3)_2(dolomite), ZrO_2, PtO_2 and LiF (0.5 wt%, as an additive) was cold isostatically pressed at 200 MPa and sintered at 1100°C for 2 h. The porous CaZrO_3/MgO/Pt composite (CaZrO_3/MgO : Pt=99 : 1 in volume) had a uniformly open-porous structure (porosity: 56%) with three-dimensional (3-D) network and a narrow pore-size distribution, similarly to the porous CaZrO_3/MgO composites reported before. Catalytic Properties (viz., NO direct decomposition and NO reduction by C_2H_4) of the CaZrO_3/MgO/Pt composite were investigated up to 900°C. In the absence of oxygen, the NO conversion rate reached ~52% for the direct decomposition and ~100% for the reduction by C_2H_4, respectively. The results suggest the possibility of the porous composite as a multifunctional filter, i.e., simultaneous hot gas-filtering and de-NO_x in one component.

• Keywords: Platinum;Nano-dispersion;In situ processing;Catalytic properties;NO_x;