The role of Mo species in Ni–Mo catalysts for dry reforming of methane†
Abstract
The Ni–Mo catalyst has attracted significant attention due to its excellent coke-resistance in dry reforming of methane (DRM) reaction, but its detailed mechanism is still vague. Herein, Mo-doped Ni (Ni–Mox) and MoOx adsorbed Ni surfaces (MoOx@Ni) are employed to explore the DRM reaction mechanism and the effect of coke-resistance. Due to the electron donor effect of Mo, the antibonding states below the Fermi level between Ni and C increase and the adsorption of C decrease, thereby inhibiting the carbonization of Ni. On account of the strong Mo and O interaction, more O atoms gather around Mo, which inhibits the oxidation of Ni and may promote the formation of MoOx species on the Ni–Mo catalyst. The presence of Mo–O species promotes the carbon oxidation, forming a unique redox cycle (MoOx ↔ MoOx−1) similar to the Mars–van Krevelen (MvK) mechanism, explaining the excellent anti-carbon deposition effect on the Ni–Mo catalyst.