Three-dimensional interconnected nanofibers consisting of ultra-small Ni-doped Co3O4 nanoparticles for acidic overall water splitting at high current density

Abstract

Exploring earth-abundant electrocatalysts to replace platinum/iridium for acidic overall water splitting at high current density is an important challenge towards lowering the cost of green hydrogen production. Herein, we developed a new class of three-dimensional interconnected nanofibers (NFs) composed of ultra-small Ni-doped Co3O4 nanoparticles (Ni-Co3O4 NFs). Benefiting from the unique ultra-small Ni-doped Co3O4 composition and three-dimensional interconnected porous structure, 13.4 % Ni-Co3O4 NFs (Ni doping is 13.4 wt%) exhibits remarkable electrocatalytic performance in acidic media. Specially, in strongly acidic environments, high activity and high stability overall water splitting can be achieved at high current density. As evidenced by the fact that a voltage of 500 mA cm−2 can be achieved at only 1.86 V and operational stability can be maintained at 500 mA cm−2 for 100 h.