Effect of electrode size on catalytic activity

In the field of catalyst research, synthesis innovations have allowed for the production of nanoparticle catalysts less than 2 nm in size. With this decrease in catalyst size, new questions have arisen with respect to the overall effect of size on catalytic activity. It is generally accepted that as catalyst particles decrease in size, the surface area to volume ratio of the catalyst is increased, resulting in higher catalytic performance. This paper introduces a novel technique for producing electrode structures with specific catalyst sizes. Through the use of electrochemical impedance spectroscopy and chronoamperometry, these different electrode sizes are compared with respect to the hydrogen evolution reaction. From this work, it is shown that for the given reaction, there exists a critical size at which catalytic activity begins to increase. A proposed explanation for the observed change in catalytic performance is introduced.