Direct Access to Oxidation-Resistant Nickel Catalysts through an Organometallic Precursor

High-performance flower-like and biocompatible nickel-coated Fe3O4@SiO2 magnetic nanoparticles decorated on a graphene electrocatalyst for the oxygen evolution reaction

The electrocatalytic oxygen evolution reaction (OER) plays a crucial role in renewable clean energy conversion technologies and has developed into an important direction in the field of advanced energy, becoming the focus of basic research and industrial development. Herein, we report the synthesis and application of flower-like nickel-coated Fe3O4@SiO2 magnetic nanoparticles decorated on a graphene electrocatalyst for the OER that exhibit high efficiency and robust durability. The catalysts were optimized using a rotating ring-disk electrode to test their oxygen evolution properties in 1.0 M KOH solution. Importantly, owing to the high specific surface area and conductivity of C3N4 and graphene, the as-synthesized Fe3O4@SiO2@NiO/graphene/C3N4 exhibits a small Tafel slope of 40.46 mV dec-1, low overpotential of 288 mV at 10 mA cm-2, and robust OER durability within a prolonged test period of 100 h. The cytotoxicity of Fe3O4@SiO2, Fe3O4@SiO2@NiO, and Fe3O4@SiO2@NiO/graphene/C3N4 was evaluated in HeLa and MC3T3-E1 cells, demonstrating that they are efficient and biocompatible catalysts for the OER. Owing to its excellent electrocatalytic efficiency and eco-friendliness, Fe3O4@SiO2@NiO/graphene/C3N4 has considerable potential as a new multifunctional composite for large-scale applications in catalysis, biology, medicine, and high-efficiency hydrogen production.

Cluster expansion and vertex substitution pathways in nickel germanide Zintl clusters

We describe the reactivity of the hypersilyl-functionalized Zintl cluster salt K[Ge9(Hyp)3] towards the nickel reagents Ni(COD)2 and Ni(Cp)2, which gives rise to markedly different complexes. In the case of Ni(COD)2 (COD = 1,5-cyclooctadiene), a dianionic sandwich-like cluster [Ni{Ge9(Hyp)3}2]2- (1) was obtained, in line with a simple ligand substitution reaction of COD by [Ge9(Hyp)3]-. By contrast, when an analogous reaction with Ni(Cp)2 (Cp = cyclopentadienyl) was performed, vertex substitution of the [Ge9(Hyp)3]- precursor was observed, giving rise to the nine-vertex nido-cluster (Cp)Ni[Ge8(Hyp)3] (2). This is the first instance of vertex substitution at a hypersilyl-functionalized Zintl cluster cage. The electrochemical behavior of these compounds was explored and showed reversible redox behaviour for both clusters.

Plasma-enhanced steam reforming of different model tar compounds over Ni-based fusion catalysts

Tar formation during biomass gasification is undesirable due to the decreased energy efficiency and increased costs for maintaining downstream equipment. The hybrid non-thermal plasma-catalysis method is considered to be a promising alternative, since it overcomes the disadvantages arising from both catalyst deactivation during catalytic reforming and the formation of undesirable liquid by-products in plasma reforming. SiO₂- and ZSM-5-supported Ni-based catalysts with different Ni loadings (0.5, 1, 3, and 5 wt%) were prepared by thermal fusion and applied to the steam reforming of toluene. Different characterizations of fresh and spent catalysts including XRD, H₂-TPR, N₂ adsorption-desorption, SEM, TEM, XPS and TGA were conducted to show the properties of catalysts. The results indicated that Ni/ZSM-5 exhibited better performance than Ni/SiO₂, due to the increased dispersion of Ni particles and the stronger metal-support interaction of Ni/ZSM-5, which was confirmed by the TEM and H₂-TPR results. In addition, the performances of the catalysis-only (CatO), plasma-only (PlO), and in-plasma-catalysis (IPC) systems in steam reforming of different model tar compounds including benzene, toluene, furfural, naphthalene, fluorene and pyrene were compared using Ni(5 wt%)/ZSM-5. Obvious synergistic effects between DBD plasma and Ni(5 wt%)/ZSM-5 was observed for syngas production in the IPC system.

Plasma-assisted catalytic reforming of toluene to hydrogen rich syngas

Ni/ZSM-5 in in-plasma catalysis systems has potential for toluene conversion, syngas formation, and inhibition of undesirable by-products and coke formation.

Plasma-assisted catalytic reforming of toluene to hydrogen rich syngas

Ni/ZSM-5 in in-plasma catalysis systems has potential for toluene conversion, syngas formation, and inhibition of undesirable by-products and coke formation.

Polymer versus phosphine stabilized Rh nanoparticles as components of supported catalysts: implication in the hydrogenation of cyclohexene model molecule

The influence of stabilizers on the catalytic performance of small rhodium nanoparticles was studied through a model hydrogenation reaction.