Perovskite-type La2-xSrxNiO4 (0 <= x <= 1) as active anode materials for methanol oxidation in alkaline solutions

Perovskite-type ternary oxides with molecular formulae, La2-xSrxNiO4 (0 <= x <= 1), were prepared by a modified citric acid sol-gel route at 600 degrees C for their possible use in a direct methanol fuel cell (DMFC). The study was conducted by cyclic voltammetry, chronoamperometry, impedance and anodic Tafel polarization techniques. The results showed that the electrocatalytic activity of the base oxide (x=0) in 1 M KOH plus 1 M CH3OH at 25 degrees C increases with x, the observed current densities being 23.6, 47.3, 43.2 and 50.9mAcm(-2) at a scan rate of 10 mVs(-1) and E=0.6V versus Hg/HgO for oxides with x=0, 0.25, 0.5 and 1.0, respectively. A I I the four perovskite anodes used in this study did not indicate any poisoning by the methanol oxidation intermediates/products. The methanol electro-oxidation reaction followed a Tafel slope of similar to 2 x 2.303RT/3F (=40 mV decade(-1)) on each oxide catalyst, regardless of Sr content. (c) 2007 Elsevier Ltd. All rights reserved.