Reactive grinding

Kaliaguine, S., Van Neste, A., Szabo, V. et al. (2001) Perovskite-type oxides synthesized by reactive grinding Part I. Preparation and characterization, Appl. Catal. A 209, 345. 

The TPR profiles of five Co-based perovskites prepared by reactive grinding with ZnO as additive for different milling times are shown in Figure 4(a-e), Figure 4f represents a LaCoOs perovskite prepared by the citrate method (referenee sample). 

Three series of LaCoi. CuxOs, LaMni.xCuxOs, LaFei x(Cu, Pd)x03 perovskites prepared by reactive grinding were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed desorption (TPD) of O2, NO + O2, and CsHg in the absence or presence of H2O, Fourier transform infrared (FTIR) spectroscopy as well as activity evaluations without or with 10% steam in the feed. This research was carried out with the objective to investigate the water vapor effect on the catalytic behavior of the tested perovskites. An attempt to propose a steam deactivation mechanism and to correlate the water resistance of perovskites with their properties has also been done. 

Three LaCoOs samples (1,11, and 111) with different specific surface areas were prepared by reactive grinding. In the case of LaCoOs (1), only one step of grinding was performed. This step allowed us to obtain a erystalline LaCoOs phase. LaCoOs (11) and LaCoOs (111) were prepared in two grinding steps a first step to obtain perovskite crystallization and a second step with additive to enhanee speeific surface area. The obtained compounds (perovskite + additive) were washed repeatedly (with water or solvent) to free samples from any traee of additive. The physical properties of the three catalysts are presented in Table 10. LaCoOs (1) was designed to present a very low specific surface area for comparison purposes. NaCl used as the additive in the case of LaCoOs (11) led to a lower surface area than ZnO used for LaCoOs (111), even if the crystallite size calculated with the Sherrer equation led to similar values for the three catalysts. The three catalysts prepared were perovskites having specific surface areas between 4.2, 10.9 and 17.2 m /g after calcination at 550 °C. A second milling step was performed in the presence of an additive, yielding an enhanced specific surface area. 

Zhang, RD Villanueva, A Alamdari, H Kaliaguine, S. Catalytic reduction of NO by propene over LaCoi.xCuxOs perovskites synthesized by reactive grinding, Catal, B Environmental, 2006, Volume 64, Issues 3-4, 220-233. 

Szabo, V Bassir, M Gallot, JE van Neste, A Kaliaguine, S. Perovskite-type oxides synthesized by reactive grinding Part III. Kinetics of n-hexane oxidation over LaCoi. xFcxOs. Appl. catal, B Environmental, 2003, Volume 42, Issue 3, 265-277. 

Zhang, RD Alamdari, H Kaliaguine, S. SO2 poisoning of LaFeo sCuo 2O3 perovskite prepared by reactive grinding during NO reduction by CsH , Appl Catal A General, 2008, Volume 340, 140-151. 

Wang LC, et al. Production of hydrogen by steam reforming of methanol over Cu/ZnO catalysts prepared via a practical soft reactive grinding route based on dry oxalate-precursor synthesis. J Catal. 2007 246(1) 193-204. 

Song, M., Lee, D. and Kwon, I. (2004) Influences on the H-2-sorption properties of Mg of Co (with various sizes) and CoO addition by reactive grinding and their thermodynamic stabilities. Metals and Materials International, 10, 69-75. 

Mn, Fe) perovskite-type catalysts prepared by reactive grinding. Appl Catal A,... 

KIT-6 aged at 100°C with the same composition synthesized by other methods (RG reactive grinding citrate synthesis using citrate complexes) [26]. 

Novel oxygen carriers for chemical looping combustion Lai ,Ce ,B03 (B = Co, Mn) perovskites synthesized by reactive grinding and nanocasting. Energy Environ. Scl, 4 (10), 4258-4269. 

Differently to this, the reactive grinding is more elaborated leading to surface areas close to those obtained by sol-gel method [30]. According to this procedure, the oxide precursors were first calcined at 600 °C and then introduced in grinder to produce the perovskite. The second step of grinding proceeded by adding an additive (ZnO or NaCl) to increase the specific surface area of the... 

Levasseur, B. and Kaliaguine, S. (2008) Methanol oxidation on LaB03 (B = Co, Mn, Fe) perovskite-type catalysts prepared by reactive grinding. Appl. Catal. A, 343, 29-38. 

Kaliaguine s group studied [26], essentially by TPR, the reducibility of LaCoOs (prepared by citrate method) and LaCoi, tCu t03 (prepared by reactive grinding) (Figure 28.1). 

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