Unravelling the reaction mechanism of gas-phase formic acid decomposition on highly dispersed Mo2C nanoparticles supported on graphene flakes

• Published in: Applied catalysis. B, Environmental Environmental, 2020-05, Vol.264 (C), p.118478, Article 118478
• Main Authors: Gray, Jake T., Kang, Shin Wook, Yang, Jung-Il, Kruse, Norbert, McEwen, Jean-Sabin, Park, Ji Chan, Ha, Su
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Carbon monoxide; CO2/CO selectivity; Computer simulation; Decarboxylation; Decomposition; Decomposition reactions; Dehydration; Eley-Rideal type mechanism; Experimental data; Formic acid; Formic acid decomposition; Graphene; High temperature; Low temperature; Molybdenum carbide; Monte carlo simulations; Nanoparticles; Reaction mechanisms; Selectivity
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118478

[Display omitted] •Used cubic molybdenum carbide nanoparticle material to study reactions of formic acid.•Evidence for gas-surface species interaction mechanism for formic acid dehydration.•Supported by Monte Carlo style simulation which replicates experimental observations. Mo2C/graphene nanostructures were used to investigate the nature of gas-phase formic acid decomposition into either CO/H2O or CO2/H2 products. The experimental data show that the Mo2C/graphene can facilitate both decarboxylation and dehydration pathways for the formic acid decomposition reaction. Its selectivity is strongly influenced by the reaction temperature where the decarboxylation predominates at a low temperature (e.g., ≤ 280 °C) and the dehydration predominates at a high temperature (e.g., ≥ 370 °C). These experimental data are compared to Monte Carlo simulations. It was found that the decarboxylation pathway for the production of CO/H2O can be simulated and explained by an Eley-Rideal type mechanism that involves interaction of gas-phase HCOOH with surface H*. Furthermore, the dehydration pathway for the production of CO2/H2 can be simulated and explained by a Langmuir-Hinshelwood type mechanism that involves unimolecular decomposition of surface HCO*O* to form CO2 and H*.