Enhanced Selective H2S Oxidation Performance on Mo2C-Modified g-C3N4

Direct catalytic selective oxidation of H2S to sulfur at low temperature has been drawing attention. Molybdenum carbide (Mo2C), in which the excess occupied orbitals provide more back-donation chances for the adsorbents' π-orbitals, shows activity in electrocatalysis, photocatalysis, thermocatalysis, etc. that are comparable to those of noble metals. This work reports for the time the use of Mo2C and Mo2C-modified g-C3N4 for catalytic selective oxidative desulfurization. The density functional theory calculation indicates that Mo2C facilitates the adsorption of H2S molecule and the HS group. Furthermore, the Mo2C-modified g-C3N4 shows a sulfur yield of as high as 99.0% at 190 °C, much higher than that of g-C3N4 (46.0%). The good stability of the catalyst was demonstrated by X-ray diffraction, Fourier transform infrared spectra, and so on. Remarkably, the H2S conversion of the Mo2C-modified g-C3N4 remains constant (95.0%) at 190 °C for as long as 30 h. As a first demonstration using carbides in selective H2S oxidation, this work provides an opportunity to develop a novel class of potential catalysts.