Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction

A high oxygen reduction reaction activity can usually be realized by increasing platinum specific activity at the expense of active surface area. Self-supported platinum-cobalt-oxide networks combining high activity and surface area now promise a stable fuel-cell operation. Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.

Automated summary

A new concept of self-supported platinum-cobalt oxide networks has been proposed, combining high specific activity with a high ECSA, promising a stable fuel-cell operation. This concept exceeds the US Department of Energy targets for Pt-related ORR mass activity.