Heat treatment temperature carbonates affected

For example, the final heat treatment temperatures In the manufacture will produce different electrochemical properties, even with the same surface treatments (2-4) since the structure and electrical property of glassy carbon depends on the temperature, as Indicated by the single crystal TEM patterns and by measurement of temperature dependent conductivity (5-6). On the other hand. It Is also well established that the electrochemical properties of carbon-based electrodes are markedly affected by surface treatments. 

Differences in the electrochemical behavior of carbons are seen with respect to their structural properties as reflected by lattice parameters. Heat treatment was found to affect the structures of heat-treated samples of Vulcan XC-72R d0 (the spacing between graphitic layers, c/2, where c is the unit cell) was found to vary with heat-treatment temperature. In Fig. 11, the lattice parameter, d0, is plotted for the various heat-treated... 

Some recent results have revealed that the optimal activity for N4-chelate catalysts is normally obtained at a heat-treatment temperature range of 500-700 °C [30-32], However, it has also been discovered that a higher pyrolysis temperature (> 800 °C) is necessary in order to achieve stable performance in a PEM fuel cell enviromnent. A deleterious effect on electrode performance was observed at temperatures higher than 1100 °C [33], Even for some carbon-supported Fe- and Co-phthalocyanines, stability can also be considerably improved. For example, an almost 50 times greater enhancement in electrocatalytic activity was achieved at an electrode potential of 700 mV (vs. NHE) when carbon-supported Co-phthalocyanine was heat-treated in an environment of N2 or Ar at 700-800 °C [34]. Furthermore, in experiments with carbon-supported Ru-phthalocyanine, heat treatment at 650 °C could increase the catalytic activity by 20 times at 800 mV (vs. NHE). Unfortunately, there was no insignificant improvement in catalyst stability. Not all heat-treated carbon-supported metal phthalocyanines gave positive results. For example, the activities and stabilities of Zn- and Mn-phthalocyanines were not affected by heat treatment [34]. The duration of heat treatment for these complexes is usually around 0.3 5 hrs. 

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