Nickel–Ceria Nanowires Embedded in Microporous Silica: Controllable Synthesis, Formation Mechanism, and Catalytic Applications

Abstract

Designing highly efficient catalysts for use in fuel production is a highly attractive research area but still remains challenging. Herein, for the first time, ultrafine Ni nanoparticles (NPs) self-assembled on ceria nanowires (NWs) and then embedded in a microporous silica shell (denoted as Ni-CeO2@SiO2) are successfully designed and synthesized via a one-pot facile strategy. The average diameter of Ni-CeO2 NWs is just 2.9 nm, and the length is up to 102.7 nm. The resulting Ni-CeO2@SiO2 exhibits high performance and 100% hydrogen selectivity for H2 production from N2H4 and N2H4BH3 in aqueous solution. Unexpectedly, Ni-CeO2@SiO2 also has good catalytic performance and thermal stability for CO2 methanation. The high catalytic performance of Ni-CeO2@SiO2 can be attributed to the synergistic electronic effect and strong interaction between Ni NPs and CeO2 NWs with plenty of oxygen vacancies, as well as the unique structure effect. As an effective strategy, the present work provides an opportunity to embed ultrafine metal NPs-CeO2 NWs into a microporous silica shell, which has broad application prospects in various catalytic fields.

Pomegranate-like Core–Shell Ni-NSs@MSNSs as a High Activity, Good Stability, Rapid Magnetic Separation, and Multiple Recyclability Nanocatalyst for DCPD Hydrogenation

“…The survey XPS spectrum ( Figure S2 ) of the Ni-NSs@MSNSs revealed the existence of Ni, Si, and O elements. 60 In the high-resolution XPS spectra, the Ni 2p 3/2 and Ni 2p 1/2 peaks at 856.5 and 874.3 eV for Ni-NSs@MSNSs were observed, corresponding to the Ni 0 species. There were Ni 2+ species with binding energies (BE) of 862.1 and 880.1 eV, respectively.…”

Noble-metal-free nanocatalysts for hydrogen generation from boron- and nitrogen-based hydrides

“…444 The resultant Ni-MoO x /BN showed excellent catalytic performance with 100% H 2 selectivity for hydrogen generation from N 2 H 4 BH 3 alkaline conditions at 323 K, giving a TOF value of 600.0 h −1 . They also developed a facile and universal methodology for the synthesis of amorphous/poorly crystallized noble-metal-free NiFe-CeO x NPs supported on a MOF substrate, and the obtained NiFe-CeO x /MOF pre-catalyst can also show 100% H 2 selectivity and record good catalytic performance for N 2 H 4 BH 3 decomposition at 343 K. 445 Recently, our group reported a wormlike Ni-CeO 2 @SiO 2 core-shell pre-catalyst with high performance (442.5 h −1 ) and 100% hydrogen selectivity for hydrogen evolution from N 2 H 4 BH 3 aqueous solution at 343 K. 405 In addition, we proposed a plausible mechanism for metal catalyzed dehydrogenation of N 2 H 4 BH 3 , which involves the chemisorption of N 2 H 4 BH 3 molecules on the metal active surface and generates the activated intermediate species. 405 Despite much progress having been made in recent years, the noble-metal-free catalysts reported above for complete hydrogen evolution from NH 3 BH 3 required a relatively high reaction temperature (≥323 K).…”

“…13). 405 The resulting wormlike core-shell-structured Ni-CeO 2 @SiO 2 pre-catalyst showed high performance and robust durability with 100% hydrogen selectivity for H 2 production from N 2 H 4 aqueous solution. The excellent catalytic properties of Ni-CeO 2 @SiO 2 can be attributed to the synergistic electronic effect and strong interactions between Ni NPs and CeO 2 NWs with plenty of oxygen vacancies, as well as the unique structure effect.…”

Achieving Complete Hydrogen Evolution from N2H4BH3 over Mesoporous TiO2 Immobilized NiPt Alloy Nanoparticles

“…Therefore, non-precious metal elements (e. g. Ni, Cu, Fe) have been an opportunity to revive scientific interest on it. [25][26][27] Nevertheless, due to its own defects of low conversion rate and poor activity, it limits practical application. In order to overcome these problems, many strategies have been proposed to the prepare alloy structures and introduce non-precious metals forming bimetallic catalysts to reduce the amount of precious metals used.…”