Enhanced methane combustion and CO oxidation with Pd and Pt substitution LaSrCuO4 perovskites

Abstract

The LaSrCuO4 as parent perovskite purely lattice was synthesized by new presented solid states technique and Pd and Pt substitution in LaSrCuO4 catalysts instead of Cu were prepared in this method at low temperature. All the perovskites were investigated by X-ray Diffraction, HRTEM, O2-TPD, H2-TPR, BET and XPS analyses. The CO oxidation and methane combustion catalytic activity of prepared perovskites were investigated which the LaSrCuO4 catalytic performance noticeably enhanced via Pd and Pt substitution instead of Cu. Both Langmuir and intra-facial mechanisms were intensified with increasing of surface area and mobility of lattice oxygen due to Pd and Pt doping in CO oxidation and methane combustion reactions. Pd 3d3/2 and 3d5/2 XPS spectra in LaSrCu0.9Pd0.1O4 confirmed Pd incorporation in perovskite structure due to presence of high oxidation state of Pd3+ or Pd4+. Pt 4 f5/2 and 4 f7/2 peaks approved Pt4+ oxidation state in LaSrCu1−xPtxO4 (x = 0.1,0.2) catalysts. The H2-TPR profiles of the Pt and Pd doped LSC perovskites revealed that the reduction peaks of the Cu were shifted to lower temperatures by increasing in Pd and Pt partial substitution due to H2-spillover effect of palladium and platinum.