Facile fabrication of Ni-based KIT-6 for adsorptive desulfurization

• Nickel was fabricated on as-synthesized-KIT-6 for the first time by one-step reduction strategy.
• Silanols and confined space between template and silica walls promoted Ni-dispersion.
• Shielding effect of capping anions of nickel precursors affect nickel dispersion and sulfur removal.
• One-step-reduction strategy save time and energy for fabricating Ni-based mesoporous silica.
• The present work may open an avenue of research by use of such confined spaces.

In the present contribution, a single step H2-reduction strategy was developed for the first time to fabricate nickel-based KIT-6 (Ni-KIT-6) for adsorptive desulfurization of fuels. As-synthesized KIT-6 was used as a support and nickel nitrate, nickel chloride and nickel acetate as a nickel precursor was directly introduced into as-synthesized KIT-6. Ni0-based KIT-6 was obtained by single-step H2-reduction strategy which not only remove template and decompose nickel precursors to NiO but also reduce NiO to Ni0. This strategy is much more convenient and facile than reported strategies for Ni-based mesoporous silica KIT-6. Characterization results show that Ni-KIT-6 with nickel content up to 30 wt.% was highly dispersed due to silanols and confined space in as-synthesized KIT-6. The percentage content (54%) of Ni0 in the as-synthesized KIT-6 is higher than Ni-based calcined KIT-6 (38%). Interestingly, Ni-based as-synthesized KIT-6 prepared using nickel nitrate as a precursor exhibited stronger nickel-KIT-6 interaction, higher Ni0 content and dispersion than those prepared with nickel chloride and nickel acetate precursors. We also demonstrate here that the shielding effect of capping anions and hydration degree of different nickel precursors significantly affect the dispersion of nickel species even using as-prepared KIT-6 as a support. As a result, Ni-KIT-6(NO3−) captured 0.195 and 0.12 mmol g−1 of sulfur from model fuel and FCC gasoline, respectively. Thus, single step H2-reduction strategy may have potential applications to be applied for fabrication of other nickel based mesoporous silicas for adsorptive desulfurization technology.

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