Biomass-derived carboxylic acids (e.g. acetic acid AcOH and formic acid FA) are a green and low-cost hydrogen source to replace hazardous H2 gas in in-situ hydrogenation processes. To date, bio-acids dehydrogenation has been mainly conducted using noble metal catalysts which would negatively impact the process economy, thus development of efficient non-noble metal catalysts for this purpose is highly desirable. In this study, the performance of transition metals supported on nitrogen doped carbon nanotubes was thoroughly evaluated by computational modelling based on Density Functional Theory (DFT). Results revealed that, out of the 10 selected transition metal candidates, molybdenum (Mo) was most active for binding AcOH and a combination of Mo and nitrogen doping significantly enhanced binding to the carboxylic acid molecules compared to pristine carbon nanotubes (CNTs). The newly designed Mo/N-CNT catalysts considerably facilitated the bio-acids decomposition compared to the non-catalytic scenarios by lowering energy barriers. FA distinctly outperformed AcOH in hydrogen donation over Mo/N-CNT catalysts, through its spontaneous cleavage leading to facile hydrogen donation.
©2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Funding: The authors would like to acknowledge financial support from the
Leverhulme Trust Research Grant (RPG-2017-254) and EPSRC First
Grant (EP/R010986/1). The authors are also grateful for computational
support from the UK Materials and Molecular Modelling Hub, which is
partially funded by the EPSRC (EP/P020194/1), for which access was
obtained via the UKCP consortium and funded by EPSRC Grant (EP/
P022561/1). Additional computational resources from the EPSRC under
the project UK Consortium on Mesoscale Engineering Sciences (UKCOMES) (Grant No. EP/R029598/1) are also gratefully
- Acetic acid
- Carbon nanotubes
- Formic acid