Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

<table class="table-group" width="800px"><tr class="fig-image" id="a"><td><img alt="491604.fig.009a" src="https://static.hindawi.com/articles/apc/volume-2012/491604/figures/491604.fig.009a.jpg"/></td></tr><tr class="fig-caption"><td align="center"><table><tr><td><b>(a) </b>300°C Pyrolysis</td></tr></table></td></tr><tr class="fig-image" id="b"><td><img alt="491604.fig.009b" src="https://static.hindawi.com/articles/apc/volume-2012/491604/figures/491604.fig.009b.jpg"/></td></tr><tr class="fig-caption"><td align="center"><table><tr><td><b>(b) </b>800°C Pyrolysis</td></tr></table></td></tr><tr class="fig-image" id="c"><td><img alt="491604.fig.009c" src="https://static.hindawi.com/articles/apc/volume-2012/491604/figures/491604.fig.009c.jpg"/></td></tr><tr class="fig-caption"><td align="center"><table><tr><td><b>(c) </b></td></tr></table></td></tr></table>

<table>Theoretical FEFF8 Δ<i>μ</i> = <i>μ</i>(Fe-N<sub>4</sub>-C<i><sub>x</sub></i>-O<sub>ads</sub>)−<i>μ</i>(Fe-N<sub>4</sub>-C<i><sub>x</sub></i>) signatures obtained for (a) 300°C and (b) 800°C pyrolysis conditions. The insets in (a, b) show the corresponding structural models utilized. Only the atoms encircled in these structural models were used for FEFF8 simulation. (c) Schematic illustration of the mono- and divacant defective pockets in amorphous carbon acting as anchors for active site formation during pyrolysis. Color codes: pink: Fe, blue: N, and black: C.</table>

Advances in Physical Chemistry

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Figure 9

Figure 9: Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media 