Multiscale engineering of molecular electrocatalysts for the rapid hydrogen evolution reaction

Molecular electrocatalysts have demonstrated potential for the hydrogen evolution reaction (HER) due to their well-defined structures and high intrinsic activities. Achieving rapid production of hydrogen requires molecular electrocatalysts to operate at high current densities, which still presents a challenge. In this work, we demonstrate that molecularly dispersed electrocatalysts of cobalt phthalocyanine anchored on carbon nanotubes (CoPc MDEs) are superior candidates due to the efficient charge transport between the substrate and the active site. The intrinsic activity can be enhanced by introducing functional groups on phthalocyanine. To facilitate mass transport, di(ethylene glycol) substituted CoPc molecules are further anchored on a three-dimensional self-supported electrode (CoPc-DEG MDE@CC), enabling continuous operation for 25 h at −1000 mA/cm² in 1.0 M KOH. Our study demonstrates the potential of molecular electrocatalysts for HER and emphasizes the importance of adjusting intrinsic activity, and charge and mass transport capacity for practical molecular electrocatalysts.