MXenes as promising catalysts for water dissociation

abstract

Two-dimensional few-layered transition-metal nitrides and carbides, called MXenes, have attracted a great interest given their large surface areas and their unique physicochemical properties. Motivated by the known reactivity of surfaces of bulk transition metal carbides on the mechanism behind the water-gas shift (WGS) reaction, density functional theory (DFT) calculations were employed to investigate the bonding of water and its dissociation on a set of eighteen M2X MXene (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, while X = C or N) surfaces. Here it is shown that all the studied MXenes exothermically adsorb water, with adsorption energies ranging from -1.43 to -2.94 eV, and greatly facilitate its dissociation, with energy barriers below 0.44 eV. These results reinforce the role of MXenes in promoting water dissociation, effectively suggesting their potential as catalysts for industrially relevant processes such as the WGS reaction.

keywords

GAS SHIFT REACTION; DENSITY-FUNCTIONAL THEORY; MOLYBDENUM CARBIDE; MECHANISM; SURFACES; GOLD; HYDROGENATION; NANOPARTICLES; ADSORPTION; NANOSHEETS

subject category

Chemistry; Engineering

authors

Gouveia, JD; Morales-Garcia, A; Vines, F; Illas, F; Gomes, JRB

Groups

G6 - Virtual Materials and Artificial Intelligence

Projects

CICECO - Aveiro Institute of Materials (UID/CTM/50011/2019)

Modeling the synthesis of SILica materials VIA multiscale computer simulations (SILVIA)

acknowledgements

The research carried out at the Aveiro Institute of Materials was developed within the scope of the project CICECO-Aveiro Institute of Materials, Refs. UID/CTM/50011/2019 and POCI/01/0145/FEDER/007679, financed by national funds through the Fundagio para a Ciencia e a Tecnologia (FCT/MCTES) and co-financed by FEDER under the PT2020 Partnership Agreement. The research carried out at the Universitat de Barcelona has been supported by the Spanish MINECO/FEDER CTQ2015-64618-R, MICIUN/FEDER RTI2018-095460-B-I00 and Maria de Maeztu MDM-2017-0767 grant and, in part, by Generalitat de Catalunya 2017SGR13 and XRQTC grants. J.D.G. is also thankful to project SILVIA with reference CENTRO-01-0145-FEDER-31002 and also to Project HPC-EUROPA3 (INFRAIA-2016-1-730897), with the support of the EC Research Innovation Action under the H2020 Programme; in particular, the author gratefully acknowledges the support of Departament de Ciencia de Materials i Quimica Fisica & Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona, and the computer resources and technical support provided by the Barcelona Supercomputing Center (BSC). A. M. -G. thanks to Spanish MICIUN for the Juan de la Cierva postdoctoral grant (IJCI-2017-31979), F. V. is thankful to Ministerio de Economia y Competitividad (MEC) for his Ramon y Cajal (RYC-2012-10129) research contract, and F. I. acknowledges additional support from the 2015 ICREA Academia Award for Excellence in University Research. Authors are thankful to Red Espanola de Supercomputacion (RES) for the supercomputing time in Marenostrum IV (QS-2019-2-0019).