Understanding Variability in the Hydrogen Evolution Activity of a Cobalt Anthracenetetrathiolate Coordination Polymer

Here, a cobalt dithiolene coordination polymer (CP) based on 9,10-dimethyl-2,3,6,7-anthracenetetrathiolate was synthesized via an interfacial reaction and was electrochemically characterized on glassy carbon (GCE) and graphite (GR) electrodes. Double-layer capacitance measurements, electrochemical impedance spectroscopy studies, and Tafel analyses were used to understand the role of electrochemically accessible active sites, electron and charge transfer, and electrical integration between the catalyst and the support in the resultant electrocatalytic hydrogen evolving activity. Overpotentials to achieve 10 mA/cm(2) ranging from 445 to 571 mV and from 388 to 527 mV for GCE vertical bar CP and GR vertical bar CP, respectively, were observed. Changes in the double-layer capacitance, which is related to electrochemically active surface area, and charge transfer resistance were determined to be the critical factors in the observed enhancement in catalytic activity, whereas bulk catalyst loading, which had been previously used to describe the hydrogen evolution reaction performance of CPs, was not the optimal indicator of catalytic activity.