Highly conductive carbon black supported amorphous molybdenum disulfide for efficient hydrogen evolution reaction

Abstract

Abstract Molybdenum disulfide (MoS 2 ) is a promising electrocatalyst for hydrogen evolution reaction (HER), however, the catalytic activity of reported MoS 2 -based materials towards HER still can't satisfy the requirement of practical application. Herein, highly conductive carbon black (CB) supported amorphous MoS 2 nanocomposite is synthesized by a facile one-pot hydrothermal process. XRD and TEM analysis proves the amorphous morphology of MoS 2 . XPS further confirms both hexagonal and orthorhombic S ligands exist in the amorphous MoS 2 . Compared with crystalline MoS 2 , amorphous MoS 2 /CB shows an onset overpotential of 78 mV and current density of 470 mA cm −2 at the overpotential of 200 mV, which is even 50% higher than that of the commercial 20% Pt/C catalyst. Furthermore, a fairly stable performance can be achieved even after 5000 CV cycles. The outstanding HER activity and stability of the amorphous MoS 2 /CB nanocomposite can be attributed to these advantages: (1) amorphous structure offers more active sites in MoS 2 ; (2) highly conductive CB reduces the charge transfer resistance (R CT ); (3) relative hydrophilic CB can largely reduce the resistance between catalyst/electrolyte interface and allows rapid mass transport; (4) electron penetration effect between amorphous MoS 2 and CB increases the intrinsic activity of amorphous MoS 2 by two orders of magnitude.