Mesoporous Ti_(0.5)Nb_(0.5)N Ternary Nitride as a Novel Noncarbon Support for Oxygen Reduction Reaction in Acid and Alkaline Electrolytes

摘要

Proton exchange membrane fuel cells (PEMFC) are of interest for potential use in a variety of power applications (i.e., automotive, portable electronics, etc.) due to their potential to efficiently convert chemical energy (i.e., hydrogen) directly to electrical energy with useful power density and low to zero emissions. Despite recent advances, several challenges continue to inhibit the full deployment of fuel cell technologies, including electrochemical stability for both catalysts and catalyst support materials and the slow kinetics of the oxygen reduction reaction (ORR) at the fuel cell cathode. Carbon black is still the most practical catalyst support for both the anode and cathode. Unfortunately, carbon is only kinetically stable under fuel cell operating conditions and has been shown to degrade after only a few hundred to a few thousand hours depending upon operating conditions. Therefore, it is necessary to explore alternatives to replace carbon support materials to improve the durability of PEMFC. Recently, much attention has been centered on the development of robust noncarbon support materials, such as carbides, ' nitrides, and conducting metal oxides.