Nickel-based perovskite

The stability but also the catalytic activity of nickel-based perovskite was improved with a low amount of magnesium or rhodium in the structure. The solubility of Mg in the perovsldte structure is limited phases such as NiO and MgO are evidenced by XRD when >0.1 in LaNii Mg >,03 [24]. High catalytic activity was reached at 700 °C, with LaNio.9Mgo.1O3 under severe reaction conditions 10 mg of catalysts, CH4/CO2 50/50 ml/min without dilution gas. The CH4 and CO2 conversion were respectively equal to 57 and 67% and maintained during 15 h on stream even if carbon deposition was detected by thermogravimetric analysis at the end of the reaction (27 wt%). 

J. Kirchenova, D. Kwana, J. Vaillancourt, J. Chaouki, 1993, Evaluation of some cobalt and nickel based perovskites prepared by freeze-drying as combustion catalysts, Catal. Lett., 21, 1-2,77-87. 

Zhao Z, Yang XG, Wu Y. (1996). Comparative study of Nickel-based perovskite-like mixed oxide catalysts for direct decomposition of NO. Appl Catal B-environ. 8, 281-97. 

Main suitable catalysts are nickel-based catalysts, titanates-based perovskite oxides, cobalt-containing catalysts. 

It is known that noble metal-based catalysts are less sensitive to coke deposit than nickel-based one. Therefore, ruthenium was used as substituent of nickel in the perovskite. De Araujo et al [26] showed that the most interesting catalyst was LaNio.8Ruo.2O3, which, in spite of being less active than LaNiOs, showed the highest resistance against carbon deposition. 

The incorporation of alkali metals in the perovskite La1 jeMjeAlo.7Nio.3O3 (M = Li, Na, K) allowed to increase the catalytic performances particularly with sodium substitution x = 0.25), while the lowest amount of coke formation was found for lithium-substituted materials (x = 0.2), proving that basic promoters improved the stability of nickel-based catalysts [41],... 

Wu, G., Li, S., Zhang, C, Wang, T., and Gong, J. (2014) Glycerol reforming over perovskite-derived nickel-based catalysts. Appl Catal B 144, 277-285. 

Several studies have been carried out aimed at synthesizing nickel-based catalysts in the most suitable form for providing high activity and better carbon resistance. Some of the nickel-based catalysts synthesized include bimetallic catalysts, oxide-supported Ni catalysts, Ni-based perovskites, and Ni core-shell structure catalysts, which are discussed in this section. 

The relatively high cost and lack of domestic supply of noble metals has spurred considerable efforts toward the development of nonnoble metal catalysts for automobile exhaust control. A very large number of base metal oxides and mixtures of oxides have been considered, especially the transition metals, such as copper, chromium, nickel, manganese, cobalt vanadium, and iron. Particularly prominent are the copper chromites, which are mixtures of the oxides of copper and chromium, with various promoters added. These materials are active in the oxidation of CO and hydrocarbons, as well as in the reduction of NO in the presence of CO (55-59). Rare earth oxides, such as lanthanum cobaltate and lanthanum lead manganite with Perovskite structure, have been investigated for CO oxidation, but have not been tested and shown to be sufficiently active under realistic and demanding conditions (60-63). Hopcalities are out-... 

Similarly to the case of direct-oxidation anode materials, sulfur-tolerant anode materials based on sulfides [6, 7] or double-perovskite oxides have special requirements for their processing into SOFC layers. For example, nickel sulfide-promoted molybdenum sulfide is tolerant to high sulfur levels [7], However, it has a low melting temperature [6] that has resulted in the development of cobalt sulfide as a stabilizer of the molybdenum sulfide catalyst [6], CoS-MoS2 admixed with Ag has an even higher performance in H2S-containing fuels than in pure H2 [6]. However, processing methods such as PS, infiltration, or sol-gel techniques that can process... 

High-performance and environmentally stable planar heterojunction perovskite solar cells based on a solution-processed copper-doped nickel oxide hole-transporting layer. Adv. Mater. 27,695-701. 

Methane or natural gas steam reforming performed on an industrial scale over nickel catalysts is described above. Nickel catalysts are also used in large scale productions for the partial oxidation and autothermal reforming of natural gas [216]. They contain between 7 and 80 wt.% nickel on various carriers such as a-alumina, magnesia, zirconia and spinels. Calcium aluminate, 10-13 wt.%, frequently serves as a binder and a combination of up to 7 wt.% potassium and up to 16 wt.% silica is added to suppress coke formation, which is a major issue for nickel catalysts under conditions of partial oxidation [216]. Novel formulations contain 10 wt.% nickel and 5 wt.% sulfur on an alumina carrier [217]. The reaction is usually performed at temperatures exceeding 700 °C. Perovskite catalysts based upon nickel and lanthanide allow high nickel dispersion, which reduces coke formation. In addition, the perovskite structure is temperature resistant. 

Tip-based oxidation experiments were first performed on Si(lll) and polycrystaline tantalum faces. - Since then a large number of materials have been locally oxidized, such as compound 111-V semiconductors silicon carbide several metals such as titanium, tantalum, aluminum, molybdenum, nickel, and niobium perovskite manganite thin films dielectrics such as silicon nitride... 

---