In-situ self-catalyzed growth of bimetallic nanoparticles/carbon nanotubes: A flexible binder-free electrocatalyst for high-performance oxygen evolution reaction

Abstract

The self-catalyzed growth of nano-structures on material surfaces is an economic and time-efficient way of designing multifunctional electrocatalysts for vast applications. NiCo bimetallic nanoparticles embedded in N-doped nanotubes (NCNTs) on carbon cloth substrate were formed here by a simple two-step method via hydrothermal treatment followed by in-situ pyrolysis and self-catalysis through chemical vapor deposition. The unique three-dimensional network and Ni/Co-N-C coordination of NiCo/NCNTs electrocatalyst provide predominant advantage for short-range and long-range conductivity and exposure of active sites. Such beneficial characteristics result in significant improvement in oxygen evolution reaction (OER) performances. The electrocatalysts obtained from two NiCo bimetallic hydroxides with different structures exhibit the overpotential of 210 and 290 mV at current density of 20 mA cm−2 and the Tafel slope of 148 and 160 mV dec−1, respectively. In addition, electrocatalysts showed long-term stability throughout 25 h with negligible lost in catalytic activities of approximately 10.6% and 12.8%, respectively.