Perpustakaan Digital ITB

Molybdenum sulfide (MoS2) is considered as low-costcatalyst with great potential for hydrogen evolution reaction (HER).In this contribution, a promising Mo-precursor wasfirst designed andprepared via partial reduction of commercial (NH4)6Mo7O24·4H2ObyDL-tartaric acid. A simple pyrolysis method as a new“bottom-up”approach was then developed to achieve the desired HER catalysts byusing the Mo-precursor. The resulting catalysts consist of multiphasic1T/2H-MoS2and residual S, N co-doped carbon (SNC) with oxygenfunctional groups. In comparison with (NH4)6Mo7O24·4H2O, Mo-precursor with high content of Mo5+promotes the full formation of MoS2, while its high content of carbon is more favorable togain the residual SNC in the resulting catalysts. The further results demonstrate that the percentages of 1T-MoS2and thecontent of the residual SNC can be facilely tuned by the pyrolysis temperatures or the Mo/S feeding molar ratios. Notably,although the resulting catalysts exhibit the“bulk”and irregular morphology with low specific surface areas, the high percentagesof 1T-MoS2as the primary advantage, the highly exposed active sites mainly stemming from disordered stacking of S?Mo?Slayers, and the high content of the SNC residues are synergistically responsible for their high electrocatalytic HER activity. Thehigh thermal stability of 1T-MoS2and the excellent durability and stability during HER processes are attributed to thestabilizing effects of the residual SNC. Under the optimized synthetic conditions, the achieved Mo/S(0.2)-450 has a lowoverpotential of?130 mV at 10 mA cm?2, a low Tafel slope of 77 mV dec?1, a high specific activity of 17.53?AcmCat.?2, andthe excellent durability and stability in 0.5 M H2SO4. This work can provide a promising Mo-precursor and a facile route todeveloping the highly efficient HER catalysts.