P,Se-Codoped MoS2 Nanosheets as Accelerated Electrocatalysts for Hydrogen Evolution

As the half reaction of water splitting, hydrogen evolution reaction (HER) is a prospective way to generate clean fuel of hydrogen. Molybdenum disulfide (MoS2), as a member of the transition-metal dichalcogenides, has attracted much research attention since its potential HER activity is predicted to be even comparable to Pt. However, the HER activity of MoS2 is still far from desirable, owing to the high resistance and limited intrinsic active sites. Herein, we have successfully engineered MoS2 by doping P and Se to regulate the electron density. The optimized P,Se-MoS2/CNTs exhibit a low overpotential of 110 mV at 10 mAcm(-2) and a small Tafel slope of 49 mVdec(-1), much better than P-MoS2/CNTs, Se-MoS2/CNTs, MoS2/CNTs, and closing to commercial Pt/C. The P,Se-MoS2/CNTs also display excellent electrochemical stability over 15 days. Raman, XPS and surface valence band spectra confirm that P and Se codoping modulate the electron densities of the catalytic sites, which can largely improve the HER activity.