Nickel-DNA complexes: bioelectrocatalysis or not?

Alkaline fuel cells (AFC) are low temperature, quick-to-start devices that can achieve 50% operating efficiency. Low cost alternatives to platinum group electrocatalysts, which allow for direct reformation are desired. Nickel electrocatalysts are highly active in alkaline for the oxidation of fuels. However, these are ‘low-density' catalysts, and in order to improve loading, complexing agents (e.g., citrate) and are utilized. Recently, much attention has been given to electrodeposited Ni-DNA complexes that give increased catalytic activity compared to their metal film counterparts, however, the mechanism is poorly understood. That is, are these complexes achieving this activity through physical or chemical mechanisms imparted by the DNA (bioelectrocatalysis) or merely the chemical constituents of DNA? Here, we set out to analyze these systems, focusing primarily on the effect of phosphate on nickel species, given the high concentration of phosphate groups within DNA.