LaCuo

Fig. 1 Two parent compounds of the family of ceramic oxides that under hole doping develop HTS. (a) In LaCuO, Lanthanum is substituted by Strontium or Barium. Ion valences, AF order, and the JT unit formed by the CuOg octahedral are shown, (b) YBaCuOy-g reaches HTS if oxygen is introduced into the Cu-0 chains. The three lattice constants for the unit cell along the three axes are a = 3.81 A, b = 3.88 A and c = 11.64 A. Average Cu-O distances are indicated as well...

Falc6n, H., Martinez-Lope, M.J., Alonso, J.A., and Fierro, JX.G. (2000) Defect LaCuOs. (S = 0.05-0.45) perovskites bulk and surface structures and their relevance in CO oxidation. Appl Catal. B, 26, 131-142. 

For methanol synthesis, the best metal choice is copper, and methanol has been obtained with Cu-containing perovskites starting with CO + H2, from CO + H2 with some percent s of CO2 and even from CO2 + H2. In the case of industrial catalysts, the amount of copper is generally high (40-60 wt%) and the productivity (kg methanol/kg of catalyst/hour) largely depends on copper metallic surfece. This can be clearly a problem when starting from Cu-based perovskites as catalyst precursor (25.4 wt% Cu for LaCuOs or 15.7 wt % for La2Cu04). 

This decomposition is confirmed for LaCuOs but neither XRD nor XPS showed evidence of Cu particles for 0.2 <. < 0.6 in LaMni CU e03 perovskite. In this case, it is suggested that Cu° particles are present as well as ionic copper form (Cu " or Cu ), ionic copper being either on the surface of Cu° particles or in close contact with their [7]. 

Figure 6. Temperature dependence of the intrinsic activity in the catalytic CO oxidation on LaCu03.5 catalysts (a) LaCuO ss (b) LaCu02 5, (c) LaCu02,73, (d) LaCu02 95 and (e) La2Cu04. Reprinted from ref 63, copyright 2000, with permission from Elsevier...

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