Al-pillared clay supported CuPd catalysts for nitrate reduction

PdCu catalysts on clay and Al-pillared clay supports were prepared by wet impregnation procedure and characterized by powder x-ray diffraction (PXRD), Scanning Electron Microscope Dispersive x-ray analysis (SEM-EDAX) and Transmission Electron Microscopy (TEM). The incorporation of [Al13O4(OH)24(H2O) 12]7+ clusters in the clay interlayers and subsequent formation of Al-pillared clays was confirmed from PXRD patterns. The EDAX analysis indicated good homogeneous mix of metallic components, in the form of monometallic or inhomogeneous bimetallic particles, on the clay and pillared clay surfaces. TEM pictures showed striking particle size differences upon Al2O3-pillaring. The metallic particles were much smaller in size on Al-pillared clay than those formed on parent clay. The clay supported PdCu catalysts were tested for nitrate ion reduction in aqueous phase under hydrogen atmosphere. Preliminary results show that the catalysts with Pd and Cu components together exhibit superior performance in activity and selectivity to nitrogen compared to their monometallic particles supported on both clay samples. This study indicates the possibility of using PdCu catalysts supported on pillared clays as environmental friendly and efficient catalysts for nitrate reduction reactions.