Mechanism and activity of the oxygen reduction reaction on WTe₂ transition metal dichalcogenide with Te vacancy

Abstract

For the first time, the oxygen reduction reaction was studied on WTe2 transition metal dichalcogenide with Te vacancy.

Mechanism of Oxygen Reduction Reaction on Monolayer WTe₂ with and without S Dopant at Low Coverage

“…The second step is the rate-limiting step of the reaction, which is the transfer of the third proton and electron. This result is also different com-pared to the literature in that the first proton and electron transfer is the rate-limiting step of the reaction[1,11,25,27]. The activation barrier for the whole process in the forward direction from left to right of the Gibbs free energy diagram was calculated by the energy difference between two steps of the HO * formation and O 2 + 4H for WTe 2 and between two steps of the HO * and O * formation for WTe 2 S. The barriers of 1.22 and 1.63 eV were obtained for the ORR in the presence of H 2 O on WTe 2 and WTe 2 S, respectively.…”

“…S doping at a low coverage was created by replacing one Te atom in perfect monolayer WTe 2 to create the WTe 2 S substrate. The substrates have the dimensions of a = b = 17.61 Å [11]. All atomic positions in the substrates and the ORR intermediates were fully optimized.…”

“…In the presence of H 2 O, we find on both substrates that the first step transfers two protons and two electrons at the same time. This process is different compared to the first hydrogenation step with only one hydrogen atom at a time for various catalytic materials in the literature[1,11,27]. The second step is the rate-limiting step of the reaction, which is the transfer of the third proton and electron.…”

“…Perfect, defective, and doped structures of TMDs could significantly enhance the ORR activity [8−10]. Besides, the ORR mechanisms on WTe2, which is a new material of the TMD family, with Te vacancies have been recently investigated [11]. However, there is no research available to elucidate the ORR mechanism and the activity on perfect and doped monolayer WTe 2 .…”

Effects of functional groups in iron porphyrin on the mechanism and activity of oxygen reduction reaction

“…The Gibbs free energy DG for each intermediate step was determined via the proton and electron exchange model. [28][29][30] The energy combining a proton and electron was equivalent to the energy of 1 2 H 2 in the gas phase at the potential of the reversible hydrogen electrode, H + + e − = 1 2 H 2 . In the standard condition (pH = 0, p = 1 bar, T = 298 K), where DE, DZPE, and DS are the reaction energy, the zero-point energy correction, and the entropy change of the intermediate step, respectively.…”