One‐Pot Facile Fabrication of Multiple Nickel Nanoparticles Confined in Microporous Silica Giving a Multiple‐Cores@Shell Structure as a Highly Efficient Catalyst for Methane Dry Reforming

Abstract

Methane dry reforming (MDR) is a very important reaction, which can efficiently use two kinds of greenhouse gases (CO2 and CH4) to prepare synthesis gas or produce green hydrogen energy. What inhibits the industrialization of MDR is the sintering of active Ni nanoparticles and severe carbon deposition for Ni‐based catalysts. To resolve these problems, a novel structured catalyst with multiple ultra‐small Ni nanoparticles (4.3 nm) as the core and microporous silica as the shell was rationally fabricated by a facial one‐pot reverse micelle method and applied for MDR. The multiple‐cores@shell (M‐Ni@SiO2) catalyst displays superior carbon resistance and long‐term durability with the methane and carbon dioxide conversion close to thermodynamic equilibrium and a H2 to CO molar ratio near 1, whereas the commercial catalyst, Ni/Al2O3, and Ni directly supported on silica spheres (Ni/SiO2) show low stability and notable carbon deposition. The ultra‐small Ni particle size and confinement effect of the porous silica shell are believed to be the determining factors for the outstanding performance of the multiple‐cores@shell catalyst. The novel multiple‐cores@shell structure catalyst could be potentially used for industrial applications of MDR.

Sandwich‐Like Silica@Ni@Silica Multicore–Shell Catalyst for the Low‐Temperature Dry Reforming of Methane: Confinement Effect Against Carbon Formation

“…NiPS@silica‐0.4 showed a higher activity than NiPS despite the low Ni loading and potentially greater diffusion resistance caused by the silica shell coating. Interestingly, in similar studies, a loss of activity caused by the shell coating is observed rarely; some core–shell catalysts also showed a higher activity than bare Ni catalysts . Li et al.…”

“…Therefore, researchers have begun to design and prepare multicore–shell or embedded catalysts. Recently, multicore–shell Ni@SiO 2 and Ni@Al 2 O 3 were prepared in a facile one‐pot procedure and showed a superb resistance to carbon formation for DRM. Another way is to take carriers that contain Ni precursors as the core instead of single metal nanoparticles .…”

Advances in catalytic conversion of methane and carbon dioxide to highly valuable products

“…Besides Al 2 O 3 , other supports were also explored. As an inert support, SiO 2 has a weak interaction with Ni, leading to relatively weak metal‐support interaction and are less stable and less active compared to mildly acidic (Al 2 O 3 ) and basic (La 2 O 3 , CeO 2 ) supports . However, the high dispersion of Ni nanoparticles in nanochannels of cerium‐modified silica aerogels or in mesoporous silica can improve the catalytic activity and thermal stability .…”

Synthesis of a Highly Active and Stable Nickel‐Embedded Alumina Catalyst for Methane Dry Reforming: On the Confinement Effects of Alumina Shells for Nickel Nanoparticles

“…Recently, core–shell‐structured Ni‐based catalysts have been researched intensively because of their excellent catalytic performance and potent coke resistance for the DRM reaction . Previous studies have shown that the inorganic SiO 2 shell can effectively stabilize Ni active species against sintering at high temperatures . Moreover, the porous voids of silica can promote the diffusion and mass transfer of the reactants .…”

“…[25][26][27] Previous studies have shown that the inorganic SiO 2 shell can effectively stabilize Ni active speciesa gainst sintering at high temperatures. [28][29][30][31][32] Moreover, the porousv oids of silica can promote the diffusion and mass transfer of the reactants. [33][34][35][36] For instance, Song et al studied aN i@SiO 2 yolkshell nanoreactor for hydrogen production, [28,37] and found that the nanoreactor framework led to high recyclability without a loss of catalytic activity because of the enhanced stability at high temperatures.…”