Plasma-Assisted Synthesis of Self-supporting porous CoNPs@C nanosheet as efficient and stable bifunctional electrocatalysts for overall water splitting.

The utilization of a highly active and robust bifunctional catalyst for simultaneously producing H2 and O2 is still a major challenging issue, which is vital for improving the efficiency of overall water splitting. Here in, we employ a novel plasma-assisted strategy to rapidly and conveniently synthesize the three-dimensional (3D) porous composite nanosheets assembled of mono-dispersed Co nanoparticles encapsulated in carbon framework (CoNPs@C) on carbon cloth (CC). Such a novel 3D hierarchical porous nanosheets improve the exposure and accessibility of active sites as well as ensure high electro conductibility. Moreover, few graphene layer coating on the surface of catalysts is in favor of improvement of the catalytic activity. Benefited from these multiple merits, the CoNPs@C composite nanosheets perform a low overpotential of 153 mV at -10 mA cm-2 for HER. Furthermore, it is also capable of catalyzing the OER with high efficiency, to achieve a current density of 10 mA cm-2 at overpotential 270 mV. Remarkably, when assembled as an alkaline water electrolyser, the bifunctional CoNPs@C composite nanosheets can afford a water-splitting current density of 10 mA cm-2 at a cell voltage of 1.65 V.