Evaluating Electrocatalysts for the Hydrogen Evolution Reaction Using Bipolar Electrode Arrays: Bi- and Trimetallic Combinations of Co, Fe, Ni, Mo, and W

Here, we report the development of a parallel electrocatalyst screening platform for the hydrogen evolution reaction (HER) using bipolar electrodes (BPEs). Electrocatalyst candidates are subjected to screening in a N-2-purged bipolar electrochemical cell where a pair of driving electrodes produce an electric field in the electrolyte solution. The HER occurring at the BPE cathodes is electrically coupled to the electrodissolution of an array of Cr microbands present at the BPE anodes. The readout of this device is simple, where the species that dissolve the most Cr microbands are identified as the most promising electrocatalyst candidates for further evaluation. We demonstrate the utility of this technique by comparing several bi- and trimetallic systems involving Co, Fe, Ni, Mo, and W, which are compared directly with pure Pt. Of all the compositions tested, Ni-8-Mo-2 is demonstrated to be the most active for the HER in a neutral electrolyte solution.