N-Doped Carbon Interior-Modified Mesoporous Silica-Confined Nickel Nanoclusters for Stereoselective Hydrogenation

Abstract

Hydrodearomatization attracts extensive interest for removing polycyclic aromatic hydrocarbons in diesel but still suffers from sluggish efficiency due to the vulnerable sulfur resistance of noble metal catalysts and inferior hydrogenation performance of traditional transition-metal catalysts. Herein, we propose a low-temperature in situ carbonization of the template strategy for constructing N-doped carbon interior-modified MCM-41 (NC@MCM)-confined ultra-dispersed Ni nanocluster catalysts (Ni/NC@MCM). The optimal hydrogenation catalyst Ni/NC300@MCM with ultrafine Ni nanoclusters (2.4 nm) exhibits 100% naphthalene conversion and 100% decalin selectivity at 100 °C and atmospheric pressure. Additionally, trans-decalin stereoselectivity up to 95% is achieved compared with other catalysts. The N-doped carbon inside mesochannels not only plays a critical role in stabilizing and dispersing Ni species but also promotes H2 adsorption/activation and enriches naphthalene molecules. Theoretical results reveal that the pyridinic-N and pyrrolic-N species can boost the adsorption of naphthalene. The dual confinement of active sites and reactants in this microenvironment makes the outstanding trans-decalin stereoselectivity a reality. Moreover, Ni/NC300@MCM shows distinguished activities in selective hydrogenation of dibenzothiophene and quinoline, and the applicability of the template carbonization method on HMS and MCM-48 is confirmed. This work opens a unique avenue in promising metal nanocluster catalysts for stereoselective hydrogenation.

Pd Nanoparticles on Carbon Supports as Electrocatalysts for the Oxygen Reduction Reaction

“…The C atoms adjacent to pyridine- N tend to react with –OH to form pyridone- N , which becomes an ORR catalytic active site . The higher content of pyridinic- N and Pd(0) in Pd/MR1-SA-CaCO 3 indicates more active sites for ORR catalysis, , which means Pd/MR1-SA-CaCO 3 should outperform rest two samples in terms of the ORR performance.…”

Increasing Ni Dispersion on a Carbon-Supported Catalyst for Hydrogenation Saturation of Naphthalene: Effect of Different Alkanol Solvents

“…After the introduction of Ni, a small part of the micropores in the samples collapse into the mesopores at high temperatures. The OH-containing alkanol solvents can easily induce the formation of an organic matrix around the Ni precursor, thereby blocking the micropores of YP80 and resulting in the formation of more mesoporous structures, which indicates that the Ni is confined to the micropores of YP80. , …”

“…The OH-containing alkanol solvents can easily induce the formation of an organic matrix around the Ni precursor, thereby blocking the micropores of YP80 and resulting in the formation of more mesoporous structures, which indicates that the Ni is confined to the micropores of YP80. 17,26 The corresponding pore size distribution (a) and N 2 adsorption isotherms (b) of the catalysts are displayed in Figure 1. All the samples had a similar pore size distribution, and the pore size of the samples was around 0−2 nm.…”

Synthesis of Mesoporous Silica Using the Sol–Gel Approach: Adjusting Architecture and Composition for Novel Applications

“…Recently, Shu et al reported the loading of nickel clusters on the surface of mesoporous MCM-41 materials, demonstrating favorable catalytic effects [ 48 ]. They initially calcined mesoporous silica containing the CTAB template at 300 °C to obtain mesoporous silica with carbon/nitrogen hybridization.…”