Nickel-based Catalyst Precursor Prepared Via Microwave-induced Combustion Method: Thermodynamics of Synthesis and Performance in Dry Reforming of CH4

Abstract

Nickel-based catalyst precursor for dry reforming of methane was successfully prepared by a self-combustion method. Three different amino acids: urea, glycine and citric acid were tested as fuels in the redox reaction with metal nitrates. For each fuel, a thermodynamic modeling of the combustion reaction was performed. The samples were characterized by X-ray diffraction (XRD), Thermogravimetric analysis (TG), Scanning electron microscopy (SEM), Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and Temperature-programmed reduction (TPR). XRD data confirmed the presence of several crystalline phases in the as-prepared powders. The sample prepared with citric acid showed very low crystallinity when compared to the other samples. It was found that the heat release rate of the self-combustion is the determinant factor of the crystallization, and it is fuel dependent. SEM results suggest that the distribution and average particle size of as-prepared powders can be controlled by the appropriate selection of the fuel. Further calcination of these samples at 800 °C/4h led to the crystallization of perovskite-type structure LaNiO 3. Nanostructured Ni 0 /La 2 O 3 obtained after reduction of LaNiO 3 precursor showed high catalytic activity in dry reforming of methane.

Role of Pr on Ni–Mg–Al Mixed Oxides Synthesized by Microwave-Assisted Self-Combustion for Dry Reforming of Methane

“…Catalyst Synthesis. The mixed oxides were synthesized by the microwave-assisted self-combustion method adapted from the work of Barros et al 33 Mg 2+ , Al 3+ , Ni 2+ , and Pr 3+ nitrates were used as precursors maintaining molar ratios of Ni/Mg = 2 and (Mg+Ni)/Al = 3, for all synthesis. Glycine was used as fuel in a molar ratio of NO 3 − /NH 2 = 1.…”

“…29 In addition, the use of microwaves as ignition technique has been proposed, demonstrating that rapid and selective volumetric heating is achieved, which could improve the advantages already mentioned in the self-combustion synthesis. 30−32 Barros et al 33 highlighted the role of microwaves on the synthesis by self-combustion (glycine as fuel) of La 2 NiO 4 /α-Al 2 O 3 catalysts, since these, compared to those prepared by impregnation, recorded higher conversions in DRM and lower carbon deposition. Besides, the promoters induce an increase in the dispersion of the active sites, control of the growth of the crystal, and increase the oxygen mobility (i.e., CeO 2 34 ), which allows a significant improvement of the activity, selectivity, and stability of the catalyst.…”

CO2 Reforming of Methane over LaNiO3 Perovskite Supported Catalysts: Influence of Silica Support

“…Some of them lead to carbon formation which leads to the deactivation of the catalyst. However, the presence of basic support such as La2O3 can improve the resistance to coke deposition [37]. We attribute the superior performance of 40 LaNiO3/SiO2 catalyst to the pres-ence of nanocrystallites of nickel (15 nm Table 1), highly dispersed on the surface of silica support.…”

Combustion synthesis and characterization of Ln1−xMxCr0.9Ni0.1O3 (Ln = La and/or Nd; M = Sr and/or Ca; x ≤ 0.25) perovskites for SOFCs anodes

“…Usually, smaller crystallite sizes are formed when the combustion temperature is not very high and, specially, when a large volume of gases is evolved because this further enhances the dissipation of heat and limits the inter-particle contact, preventing grain growth. The comparison of combustible substances in the literature [15,28,29], however, are not definitive regarding to which one results in smaller particles mainly because each author uses different combustible to oxidizer ratios, which has a strong influence on the combustion temperature [30], so those results are not easily comparable. In the present case, our results indicate that glycine and urea combustion yield smaller particles than sucrose probably because non-nitrogen containing combustibles are not as efficient dissipating the combustion temperature than the nitrogen ones.…”