Synthesis of Manganese Silicide Nanowires by Thermal Chemical Vapor Deposition for the Hydrogen Evolution Reaction

Thermal chemical vapor deposition investigated the growth-aligned manganese silicide (MnSi) nanowires on a c-Si(111) substrate. The growth, composition, and morphology of MnSi nanowires were studied in detail using X-ray diffraction, transmission electron microscopy, field emission electron microscopy, and X-ray photoelectron spectroscopy at different reaction pressures (0.03, 0.12, 0.52, 1.20, and 6.20 mbar). The effect of reaction pressure on the electrocatalytic activity of MnSi nanowires in the hydrogen evolution reaction (HER) was explored further. Compared to higher pressure, at lower pressure (0.12 mbar), the as-synthesized MnSi nanowire exhibits the greatest electrocatalytic performance (1.2 mbar). The electrochemical impedance spectroscopy analysis revealed that the increase in HER electrocatalytic activity of MnSi nanowires at a lower reaction pressure of 0.12 mbar is associated with increasing number of charge carriers transported by a reducing diameter of the nanowires, which is a function of the reaction pressure.