Catalytic performance of the Ce-doped LaCoO3 perovskite nanoparticles

Abstract

A series of La1-xCexCoO3 perovskite nanoparticles with rhombohedral phases was synthesized via sol–gel chemical process. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Electron Diffraction Spectroscopy (EDS), Thermogravimetric Analysis (TGA), UV–Vis spectroscopy, Fourier Transform Infrared spectra (FTIR), Nitrogen Adsorption/desorption Isotherm, Temperature Program Reduction/Oxidation (TPR/TPO), X-ray Photoelectron Spectroscopy (XPS) techniques were utilized to examine the phase purity and chemical composition of the materials. An appropriate doping quantity of Ce ion in the LaCoO3 matrix have reduced the bond angle, thus distorting the geometrical structure and creating oxygen vacancies, which thus provides fast electron transportation. The reducibility character and surface adsorbed oxygen vacancies of the perovskites were further improved, as revealed by H2-TPR, O2-TPD and XPS studies. Furthermore, the oxidation of benzyl alcohol was investigated using the prepared perovskites to examine the effect of ceria doping on the catalytic performance of the material. The reaction was carried out with ultra-pure molecular oxygen as oxidant at atmospheric pressure in liquid medium and the kinetics of the reaction was investigated, with a focus on the conversion and selectivity towards benzaldehyde. Under optimum reaction conditions, the 5% Ce doped LaCoO3 catalyst exhibited enhanced catalytic activity (i.e., > 35%) and selectivity of > 99%, as compared to the other prepared catalysts. Remarkably, the activity of catalyst has been found to be stable after four recycles.

Cobalt Element Effect of Ternary Mesoporous Cerium Lanthanum Solid Solution for the Catalytic Conversion of Methanol and CO2 into Dimethyl Carbonate

“…Figure 1 also showed that Ce-La-Co appears with weak peaks at the positions of 2θ of 32.88° and 58.96°. The positions of these diffraction angles are consistent with the three strong peaks (32.58°, 47.48°, 58.98°) of LaCoO 3 perovskite, and it may be a trace amount of LaCoO 3 perovskite [ 19 ]. Comparing the diffraction peaks of Ce-La solid solution before doping, it was found that the diffraction peaks (111) and (200) of partial crystal planes of the prepared solid solution samples shifted to high angles, indicated M n+ ions were embedded in the fluorite structure of Ce-La solid solution [ 20 ].…”

Catalytic feasibility of Ce-doped LaCoO3 systems for chlorobenzene oxidation: An analysis of synthesis method

“…The addition of Ce induces changes in the reducibility of LaCoO 3 perovskite, evidenced by the shift of the first peak to lower temperatures, the overlapping of the two signals of the second peak and a shift of this peak to higher temperatures. The same was observed by other authors, [34][35][36] with the same perovskites. The deconvolution of this second signal is shown in order to enhance the visualization.…”

“…Ce 4+ [36]. As can be seen in Table 4, the Ce 3+ /Ce 4+ ratio decreased from 1.6 to 1.1 for RG0.05 and RG0.5, respectively.…”

Investigation of Structural and Thermal Evolution in Novel Layered Perovskite NdSrMn2O5+δ via Neutron Powder Diffraction and Thermogravimetric Analysis

“…In the first step (200 °C-500 °C), the weight loss was high due to the moisture evaporation [47], and the decline in this region was about 0.084%. Above 500 °C, the weight loss was less because all the organic compounds and all other elements end up in this step and the sample behaves as a thermally stable material [48][49][50][51][52][53]; from 500 °C to 950 °C, the weight loss was approximately 0.016%. e total weight loss observed was about 0.10% for a temperature range between 20 and 950 °C which is comparable with other perovskite materials; SmBaMn 2 O 5+δ (0.036%) [54] and PrSrMn 2 O 5+δ [30].…”