On the multifaceted roles of NiSx in hydrodearomatization reactions catalyzed by unsupported Ni-promoted MoS2

Study on the Performance of Ni–MoS2 Catalysts with Different MoS2 Structures for Dibenzothiophene Hydrodesulfurization

“…There is about 854.1 eV binding energy for the Ni 2p 3/2 peak for the Ni–Mo–S active phase, 853.2 eV for Ni x S y , and 856.7 eV for oxidized Ni 2+ species. , The peaks observed at an energy level of 862.2 eV are attributed to the shakeup satellite structures originating from the Ni 2p 3/2 orbital . Many studies concluded that Ni x S y in the catalyst is less active in the HDS reaction, − but the presence of a certain amount of Ni x S y can take a synergistic effect with MoS 2 , making the hydrogen spillover effect more effective and thus improving the HYD selectivity of DBT. ,− The proportion of active species at different hydrothermal treatment temperatures is shown in Table . The relative proportions of active species (Ni–Mo–S + Ni x S y ) decrease in the following order: H-NiMo-150–400 > H-NiMo-120–400 > H-NiMo-180–400 > H-NiMo-90–400 > H-NiMo-200–400.…”

“…This result is due to the decomposition of part of the Ni–Mo–S structure into Ni 3 S 2 when H-NiMo-150–500 and H-NiMo-150–600 are calcined in a H 2 atmosphere, which leads to an increase in the Ni x S y /Ni–Mo–S ratio. The mutual contact between Ni x S y and MoS 2 plates partially limits the accessibility of S vacancies in MoS 2 plates, making the DBT DDS reaction pathway limited. , Meanwhile, the hydrogen spillover phenomenon between Ni x S y and MoS 2 makes the catalyst more selective for the HYD pathway . In contrast to other catalyst samples, DBT reacted with the highest HYD/DDS of 1.34 on the N-NiMo-150–400 sample prepared by calcination in a N 2 atmosphere.…”

“… 1 Many studies concluded that Ni x S y in the catalyst is less active in the HDS reaction, 62 − 64 but the presence of a certain amount of Ni x S y can take a synergistic effect with MoS 2 , making the hydrogen spillover effect more effective and thus improving the HYD selectivity of DBT. 59 , 65 − 68 The proportion of active species at different hydrothermal treatment temperatures is shown in Table 3 . The relative proportions of active species (Ni–Mo–S + Ni x S y ) decrease in the following order: H-NiMo-150–400 > H-NiMo-120–400 > H-NiMo-180–400 > H-NiMo-90–400 > H-NiMo-200–400.…”

“…The mutual contact between Ni x S y and MoS 2 plates partially limits the accessibility of S vacancies in MoS 2 plates, making the DBT DDS reaction pathway limited. 65 , 86 Meanwhile, the hydrogen spillover phenomenon between Ni x S y and MoS 2 makes the catalyst more selective for the HYD pathway. 65 In contrast to other catalyst samples, DBT reacted with the highest HYD/DDS of 1.34 on the N-NiMo-150–400 sample prepared by calcination in a N 2 atmosphere.…”

“…Interestingly, the HYD pathway selectivity of DBT on the catalysts increased with increasing calcination temperature in a H 2 atmosphere at the same hydrothermal treatment temperature and even the selectivity of the HYD pathway of DBT over that of the DDS pathway appeared in the H-NiMo-150− plates partially limits the accessibility of S vacancies in MoS 2 plates, making the DBT DDS reaction pathway limited. 65,86 Meanwhile, the hydrogen spillover phenomenon between Ni x S y and MoS 2 makes the catalyst more selective for the HYD pathway. 65 In contrast to other catalyst samples, DBT reacted with the highest HYD/DDS of 1.34 on the N-NiMo-150−400 sample prepared by calcination in a N 2 atmosphere.…”