Direct borohydride oxidation: mechanism determination and design of alloy catalysts guided by density functional theory

Abstract

Direct borohydride fuel cells (DBFCs) convert an aqueous soluble, high specific energy density borohydride fuel directly to electrical energy. The lack of effective anode electrocatalysts for the anodic oxidation of borohydride limits the efficiency and power density attainable in these devices. The complexity of the eight electron reaction makes experimental determination of the reaction mechanism extremely challenging, thereby hampering the development of a rationale for optimizing catalyst composition. Computational quantum mechanical methods provide a unique tool for evaluating elementary step reaction kinetics in this system, and can be applied to guide a rational catalyst design procedure. In this perspective, we review the experimental literature on borohydride oxidation catalysis and discuss the usefulness of quantum mechanical methods towards electrode design. Mechanistic insights provided by these computational methods are discussed as well as the prospects of applying a computationally guided design procedure towards developing novel catalyst compositions.