Highly-dispersed cobalt clusters decorated onto nitrogen-doped carbon nanotubes as multifunctional electrocatalysts for OER, HER and ORR

Preventing agglomeration and corrosion of metal electrocatalysts at nanoscale is crucial for electrochemical energy conversion, such as fuel cell and overall water splitting, where all the oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) are the core. Herein, an effective strategy is developed for preparing multifunctional self-supporting electrocatalysts with uniformly distributed cobalt nanoparticles and clusters. Benefiting from good electrical conductivity and multiple active sites, the trifunctional self-supporting catalyst free from stacking and aggregating exhibits excellent OER and HER activities with an overpotential of 270 and 110 mV to obtain a current density of 10 mA cm−2 in alkaline media. The ORR performance was tested in 0.1 M KOH solution with a half-wave potential of ∼0.80 V and a limiting current density of ∼ −4.8 mA cm−2. Our finding provides an opportunity for the rational design of multifunctional and highly-efficient self-supporting electrocatalysts towards the integration of electrochemical energy conversion.