Hydrogen donation of bio-acids over transition metal facets: A density functional theory study

Zhang, Jiajun; Zhang, Xiaolei; Osatiashtiani, Amin; Bridgwater, Anthony V.

doi:10.1016/j.apcata.2019.117218

Cited by 6 publications

(20 citation statements)

References 51 publications

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“…revealed Mo improved the adsorption energy of AcOH dramatically compared with the adsorption onto non-metal loading CNTs, confirming the binding promotion effect of Mo to the AcOH adsorption, in line with recent study [5]. Over Mo/N p -CNT, AcOH exhibited higher binding energy, ascribed to the unpaired electron of pyridinic N acts as electron acceptor (Lewis acid), such that reinforces the binding between the catalyst and adsorbate molecule [34].…”

Section: Results and Discussion 21 Catalyst Designsupporting

confidence: 87%

“…Interestingly, dissociative adsorption was observed when AcOH bonded to the Mo/N p -CNT through O β -Mo, where the molecule decomposed into hydroxyl and acetyl (Ac) during the adsorption. The dissociative adsorption is common for molecular hydrogen adsorption over transition metals [4], but it is the first time observed for the AcOH adsorption, and has not been observed onto Mo surface in our recent study, neither over Mo/N g -CNT [5]. [13,38,39], with the merit that little hurdles before the hydrogen donation.…”

Section: Results and Discussion 21 Catalyst Designmentioning

confidence: 68%

“…The adsorption energy of AcOH over the pure metal facets [5] is also shown for comparison in the are established and demonstrated in Fig. 2, along with the intact CNT model.…”

Section: Results and Discussion 21 Catalyst Designmentioning

confidence: 99%

“…The dehydroxyl reaction was also reported over the Cu (111) facet, but with higher energy barrier [7]. Compared to the decomposition of FA over pure Mo [5], nitrogen doped CNTs exhibit better performance in terms of facilitating hydrogen donation by lowering the energy barriers and less reaction steps.…”

Section: Fa As Hydrogen Donor Over Mo/n-cntsmentioning

confidence: 95%

“…Our recent research demonstrated bio-acids (i.e. acetic acid and formic acid) possess great potential as hydrogen donors for catalytic fast pyrolysis of biomass over Mo (110) facet due to their exothermic property and lower energy barriers during the decomposition [5].…”

Section: Introductionmentioning

confidence: 99%

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The mechanistic investigation on hydrogen donation performance of bio-acids over bi-functional carbon nanotube catalysts

Zhang

2020

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Background Bio-acids such as acetic acid (AcOH) and formic acid (FA) are typical bio-oil compounds and platform chemicals that sourced from biomass pyrolysis. They are attracting global research attention due to their low-cost and safety merits with additional potentials as alternative in-situ hydrogen donors for bio-oil upgrading. However, the hydrogen donation performance of bio-acids have not been sufficiently evaluated, especially, investigation on high efficient catalysts to promote the process is lacking. In this study, novel catalysts of metal supported on nitrogen doped carbon nanotubes (CNTs) were thoroughly evaluated in facilitating the decomposition of both FA and AcOH for hydrogen donation by comparing ten different metal loadings and six types of CNT based substrates. Results It was found that Mo loading enabled the strongest binding energy to the bio-acid molecule among the ten evaluated transition metals, and Np (pyridinic nitrogen doped)-CNT led to bigger adsorption energy of AcOH than other substrates, e.g. Ng (graphitic nitrogen doped)-CNT or non-doped CNT. The new designed catalyst, Mo/N-CNTs, considerably facilitated the bio-acids decomposition by lowering the energy barriers, compared to the non-catalytic scenario. The favourable hydrogen donation pathways for AcOH are: CH3COOH→CH3CO→CH3→CH2→CH→C over Mo/Np-CNT, and CH3COOH→CH3CO→CH3C→CH3→CH2→CH1→C over Mo/Ng-CNT. The pathways for FA are: HCOOH→H+CO+OH over Mo/Np-CNT and HCOOH→HCO+OH over Mo/Ng-CNT. FA has showed the superiority for hydrogen donation than AcOH over Mo/N-CNT catalysts since it can be cleaved into hydroxyl group and hydrogen without an energy barrier, which will facilitate the following hydrogen donation from hydroxyl. Conclusions It was concluded that the new explored catalyst, Mo/N-CNTs, significantly lowered the decomposition energy barriers for both AcOH and FA thus promoting the hydrogen donation performance of both bio-acids. Additionally, over the designed catalyst, FA is a preferred hydrogen donor than AcOH due to the barrier-free adsorption step while the energy barriers for AcOH decompositions are relatively high.

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Section: Results and Discussion 21 Catalyst Designsupporting

confidence: 87%

Section: Results and Discussion 21 Catalyst Designmentioning

confidence: 68%

“…The adsorption energy of AcOH over the pure metal facets [5] is also shown for comparison in the are established and demonstrated in Fig. 2, along with the intact CNT model.…”

Section: Results and Discussion 21 Catalyst Designmentioning

confidence: 99%

Section: Fa As Hydrogen Donor Over Mo/n-cntsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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The mechanistic investigation on hydrogen donation performance of bio-acids over bi-functional carbon nanotube catalysts

Zhang

2020

Preprint

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Understanding the heterogeneous catalytic mechanisms of glycerol carbonate synthesis on oil palm ash surface: A density functional theory approach

Delesma

Okoye

Castellanos-López

et al. 2022

Fuel

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The mechanism of hydrogen donation by bio-acids over metal supported on nitrogen-doped carbon nanotubes

Zhang

Osatiashtiani

et al. 2021

Molecular Catalysis

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Biomass-derived carboxylic acids (e.g. acetic acid AcOH and formic acid FA) are a green and low-cost hydrogen source to replace hazardous H 2 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.

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Hydrogen donation of bio-acids over transition metal facets: A density functional theory study

Cited by 6 publications

References 51 publications

The mechanistic investigation on hydrogen donation performance of bio-acids over bi-functional carbon nanotube catalysts

The mechanistic investigation on hydrogen donation performance of bio-acids over bi-functional carbon nanotube catalysts

Understanding the heterogeneous catalytic mechanisms of glycerol carbonate synthesis on oil palm ash surface: A density functional theory approach

The mechanism of hydrogen donation by bio-acids over metal supported on nitrogen-doped carbon nanotubes

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