Boosting the activity of transition metal carbides towards methane activation by nanostructuring. Issue 13 (23rd March 2020)

• Record Type: Journal Article
• Authors: Figueras, Marc; Gutiérrez, Ramón A.; Prats, Hector; Viñes, Francesc; Ramírez, Pedro J.; Illas, Francesc; Rodriguez, José A.
• Is Part Of: Physical chemistry chemical physics. Volume 22:Issue 13(2020)
• Page Start: 7110
• Page End: 7118
• Publication Date: 2020-03-23
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d0cp00228c
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Molybdenum carbide breaks methane by going nano. Abstract : The interaction of methane with pristine surfaces of bulk MoC and Mo2 C is known to be weak. In contrast, a series of X-ray photoelectron spectroscopy (XPS) experiments, combined with thermal desorption mass spectroscopy (TDS), for MoC y ( y = 0.5–1.3) nanoparticles supported on Au(111)—which is completely inert towards CH4 —show that these systems adsorb and dissociate CH4 at room temperature and low CH4 partial pressure. This industrially-relevant finding has been further investigated with accurate density functional theory (DFT) based calculations on a variety of MoC y supported model systems. The DFT calculations reveal that the MoC y /Au(111) systems can feature low C–H bond scission energy barriers, smaller than the CH4 adsorption energy. Our theoretical results for bulk surfaces of Mo2 C and MoC show that a simple Brønsted–Evans–Polanyi (BEP) relationship holds for C–H bond scission on these systems. However, this is not the case for methane activation on the MoC y nanoparticles as a consequence of their unique electronic and chemical properties. The discovery that supported molybdenum carbide nanoparticles are able to activate methane at room temperature paves the road towards the design of a new family of active carbide catalysts for methane activation and valorisation, with important implications in climate change mitigation and carbon cycle closure.