Polymorphs of a copper coordination compound: interlinking active sites enhance the electrocatalytic activity of the coordination polymer compared to the coordination complex

Abstract

Copper–pyridinedicarboxylic acid produces concomitant polymorphs, a copper complex (Cu–C) and a coordination polymer (Cu–P), which have a similar coordination environment but completely different electrocatalytic activity. Cu–P displayed highly enhanced activity for the hydrogen evolution reaction (HER, η@10 mA cm⁻² = 285 mV, j_max = 161.7 mA cm⁻²) compared to Cu–C (η@10 mA cm⁻² = 444 mV, j_max = 48.7 mA cm⁻²) in a neutral medium.