Density Functional Theory Investigation on Thiophene Hydrodesulfurization Mechanism Catalyzed by ReS₂ (001) Surface

Abstract

We present density functional theory calculations on the reaction mechanism of thiophene hydrodesulfurization (HDS) over ReS2 (001) surface under typical HDS reaction conditions. It is found that thiophene adopts an “upright” adsorption configuration with the binding energy of 1.26 eV. Considering the factors such as Bader charge, two reaction mechanisms, named direct desulfurization (DDS) to the product of butadiene and hydrogenation (HYD) to 2-butene, 1-butene, and butane, are systematically investigated. Results show that H prefers to attack thiophenic C before the first C–S bond rupture but begins to hydrogenate ST (S atom of thiophene) after ring-opening. Prehydrogenation has different effect on the activity of C–S bond breaking. When the ring is intact, it has nominal effect; but when the ring is open, appropriate prehydrogenation can dramatically decrease the energy barrier while complete hydrogenation makes the barrier rise again due to stereohindrance effect. The DDS mechanism is proved to be kinetically unfavorable while 2-butene is suggested to be a predominated product for HYD mechanism. The role of Sa (preadsorbed S) is a “ladder” which helps H approach the thiophenic molecule while ST acts as an “intermediary” for H exchange. Changing reaction conditions through partial pressure of H2 can only alter the rate-determining step but has nothing to do with the catalytic selectivity.

Adsorption and Desulfurization Mechanism of Thiophene on Layered FeS(001), (011), and (111) Surfaces: A Dispersion-Corrected Density Functional Theory Study

“…Similar high activation energy barriers and endothermicity have been reported for the direct desulfurisation pathway of thiophene on the ReS 2 (001) surface 24 and on transition-metal carbides and nitride. 8 , 75 On the ReS 2 (001) surface, 24 the breaking of the first and second C–S bonds needs to surmount activation energy barriers of 1.76 and 1.85 eV, respectively, whereas on the NbC(001) surface, 74 activation energy barriers of 1.74 and 1.82 eV have to be overcome. Similarly, on the VC(001) surface, 8 the scission of the first and second C–S bonds needs to overcome activation energy barriers of 1.49 and 1.88 eV, respectively.…”

“…Similar results were previously reported for thiophene adsorption on other layered materials including MoS 2 5 , 16 , 17 and ReS 2 . 24 The lowest-energy stable adsorption configuration of thiophene on the stoichiometric FeS(011) surface is a tridentate structure (denoted as η 3 (2C, S) as shown in Figure 6 b). In this structure, the thiophene molecule is adsorbed on the surface via two short C–Fe bonds of average length 2.133 Å and one S–Fe bond of length 2.331 Å.…”

“…Recently, the reaction mechanism of thiophene hydrodesulfurization over the ReS 2 (001) surface under typical HDS reaction conditions was investigated using density functional theory calculations. 24 The adsorption kinetics of thiophene on WS 2 nanoparticles with fullerene-like (onion-like) structures has been studied under ultrahigh vacuum conditions by sample temperature ramping techniques. 25 It was shown that at low temperatures, the thiophene adsorbs molecularly, whereas the formation of H 2 S and alkanes was observed at higher temperatures on the reduced and oxidized WS 2 nanoparticles.…”

Highly Efficient Photocatalytic Hydrogen Evolution by ReS2 via a Two‐Electron Catalytic Reaction

“…89‐0341), verifying the result determined by HRTEM. The good exposure of the (001) facet of the ReS 2 NWs ensured that more active sites were available for hydrogen adsorption, thus improving the catalytic activity, which was further supported by the PHE measurements.…”

Novel Insights and Perspectives into Weakly Coupled ReS2 toward Emerging Applications

“…Apart from the application in HER, ReS 2 also has been reported to efficiently catalyze the process of hydrodesulfurization 58,59 and guaiacol conversion 60,61 as a result of the synergic effect between electronic nature and the weak interlayer coupling of ReS 2 . Moreover, it was predicted that hydrogen adsorption and dissociation could easily take place at the Re sites on the (001) surface of ReS 2 in hydrotreating reactions.…”