Self-crosslinkable polyaniline with coordinated stabilized CoOOH nanosheets as a high-efficiency electrocatalyst for oxygen evolution reaction.

• The assembly of ultrathin CoOOH nanosheets into the PANI network can be realized as OER catalyst. • The nitrogen species derived from PANI can work as bridging sites to coordinate with Co metal ions. • The electron delocalization of Co/PANI HNSs can regulate its own electronic structural states. • The Co/PANI HNSs presents a hierarchical porous with both structure of mesopores and macropores. • The high-stability Co/PANI HNSs catalyst can afford a low overpotential with a small Tafel slope. Polyaniline (PANI)-based composite materials have shown to be promising candidates for oxygen evolution reaction (OER) electrocatalysts because of their non-ignorable merits of conductivity, flexibility, durability and environmental friendly. Herein, we develop a facile strategy to realize in-situ assembly of CoOOH nanosheets into the PANI network, which is denoted as Co/PANI HNSs for OER performance. The nitrogen species derived from PANI building blocks can work as bridging sites to preferentially coordinate with Co metal ions, which impart coupling effects between CoOOH nanosheets and PANI as well as the structure stability. Besides the Co-N coordination, the occurred electron delocalization between Co d-orbitals and PANI π-conjugated ligands can also modulate the electronic structural states of Co/PANI HNSs, enabling the efficient interfacial electron transfer from CoOOH to PANI. In addition, the Co/PANI HNSs possesses a hierarchical porous with both structure of mesopores and macropores that allows electrolyte to be more efficiently transported to the highly oxidative active sites, resulting in fast reaction kinetics. In recognition of these advanced structural characteristics, the Co/PANI HNSs electrocatalyst can give a low overpotential of 291 mV at an anodic current density of 10 mA cm−2 and a small Tafel slope of 54 mV dec−1 in 1 M KOH electrolyte as well as a good durability. [ABSTRACT FROM AUTHOR]