Facile synthesis of high surface area molybdenum carbide nanoparticles

Abstract

Molybdenum carbide has immense potential as an active catalyst for reaction systems such as synthesis of important chemicals like ammonia. However, the carbide is not used as a commercial catalyst or support as the current synthesis processes produce low surface area material or have contaminants such as excess carbon and surface and chemisorbed oxygen. Moreover, attempts to refine the synthesis pathways are usually not supported by any thermochemical modeling. In this study, a facile and reproducible method to synthesize high surface area molybdenum carbide was developed with the help of thermochemical modeling to better understand molybdenum‐carbon phase behavior. We have synthesized 2‐5 nm particles of MoxC with surface areas of up to 360 m2/g as characterized using a variety of techniques including X‐ray diffraction and electron microscopy.

Nanoparticle Size Effects on Phase Stability for Molybdenum and Tungsten Carbides

“…Our comparison focuses on average particle size and neglects particle size distributions (reported in only a subset of studies); we emphasize that our goal is to broadly compare the trends between particle sizes and phases in the literature. The δ-MoC phase dominates the smaller particle size ranges, ,,,,,,− in agreement with our calculations, although there are a few reports of δ-MoC at larger sizes. ,,, Similarly, η-MoC has been synthesized only at small particle sizes <6 nm. ,− The α-Mo 2 C phase has been experimentally synthesized − across a wide range of particle sizes, weighted more heavily toward larger particle sizes, consistent with Figure a. The β-Mo 2 C phase is close in free energy to α-Mo 2 C at all Δμ C and all particle sizes (Figures a,b and S6) and is similarly represented in a wide range of sizes (excluding the 0–3 nm range). ,,,,− ,,,− The one notable exception is the γ-MoC phase, predicted to be more stable at larger particle sizes, which has been synthesized with similar representation at both small (3–6 nm) , and large (>9 nm) − particle sizes and does not appear to follow a trend.…”

Study on the reduction of commercial MoO3 with carbon black to prepare MoO2 and Mo2C nanoparticles

“…Over the past decades, molybdenum carbide is one of most widely studied transition metal carbides due to its remarkable physical and chemical properties, such as high electrical conductivity, outstanding catalytic properties, good thermal stability, high hardness, large adsorption capacity, excellent corrosion, and wear resistances . These excellent properties make it potential candidate for a variety of applications including electro‐catalytic reaction, hydrogenation and hydrogen evolution reactions, methane reforming, hydrodesulfurization catalyst, metal ceramics, and cutting tools .…”

Rapid synthesis of high-purity molybdenum carbide with controlled crystal phases

“…By adjusting the electron transfer between platinum and molybdenum carbide, the redox state and active sites of platinum can be optimized, thereby enhancing its catalytic performance. 1,4,11 44 (2) pyrolysis of Mo(VI)-melamine hybrid (solid-solid reaction), 33 (3) single-step thermal carburization method (solid-solid reaction), 53 (4) pyrolysis of organic-inorganic hybrid nanocomposites (solid-solid reaction), 28 (5) carburization of Mo-containing resin precursors (solid-gas reaction), 22 (6) carburization of Mo precursor (solid-gas reaction), 35 (7) molten salt synthesis method (solid-solid reaction), 54 (8) carburization of Mo-containing resin precursors (solid-gas reaction), 37 and (9) carburization of Mo-containing resin precursors (solid-gas reaction). 55 This journal is © The Royal Society of Chemistry 2024…”