Carbon Nanotubes with Cobalt Corroles for Hydrogen and Oxygen Evolution in pH 0-14 Solutions

Water splitting is promising to realize a hydrogen-based society. The practical use of molecular water-splitting catalysts relies on their integration onto electrode materials. We describe herein the immobilization of cobalt corroles on carbon nanotubes (CNTs) by four strategies and compare the performance of the resulting hybrids for H-2 and O-2 evolution. Co corroles can be covalently attached to CNTs with short conjugated linkers (the hybrid is denoted as H1) or with long alkane chains (H2), or can be grafted to CNTs via strong pi-pi interactions (H3) or via simple adsorption (H4). An activity trend H1 >> H3> H2 approximate to H4 is obtained for H-2 and O-2 evolution, showing the critical role of electron transfer ability on electrocatalysis. Notably, H1 is the first Janus catalyst for both H-2 and O-2 evolution reactions in pH 0-14 aqueous solutions. Therefore, this work is significant to show potential uses of electrode materials with well-designed molecular catalysts in electrocatalysis.