Influence of Highly Stable Ni2+ Species in Ni Phyllosilicate Catalysts on Selective Hydrogenation of Furfural to Furfuryl Alcohol

Enhancing the catalytic performance of non-noble Ni catalysts in the selective hydrogenation of furfural to furfuryl alcohol (FA) in terms of furfural conversion, selectivity, and good recyclability is challenging. Here, spherical nickel phyllosilicate catalysts (Ni_PS) with fibrous-like structures are prepared via a modified sol-gel method with Ni loadings of 2-30 wt %. Upon exposure to air, all the reduced Ni_PS catalysts exhibit more than 80% Ni⁰/Ni_{phyllosilicate} species on the surface, whereas a large portion of Ni oxide species (>55%) is presented on the impregnated catalyst. The Ni²⁺ species in nickel phyllosilicate catalysts are active and highly stable during reduction, reaction, and regeneration, yielding stable catalytic performance for multiple recycle tests in furfural hydrogenation to FA. Furfural conversion over the Ni_PS catalysts increased monotonically with increasing Ni loading without an FA selectivity drop. The presence of both metallic Ni⁰ and Ni_{phyllosilicate} also produces a synergistic promotional effect for FA formation.

Selective hydrogenation of CO2 to CH4 over two-dimensional nickel silicate molecular sieves

Two-dimensional (2D) Ni-containing delaminated MWW layers (Ni-DML) were synthesized by hydrothermal treatment of a borosilicate MWW precursor with a nickel nitrate solution, and their catalytic properties were investigated for the...

Defect-stabilized nickel on beta zeolite as a promising catalyst for dry reforming of methane

Four different Ni-containing beta zeolite (Ni-BEA) catalysts were synthesized and applied for dry reforming of methane (DRM). Ni-BEA(I) exhibiting a nickel silicate was synthesized via the single-step interzeolite transformation of...

Ultrasound-assisted sequentially precipitated nickel-silica catalysts and its application in the partial hydrogenation of edible oil

Sequentially precipitated Mg-promoted nickel-silica catalysts with ageing performed under various ultrasonic intensities were employed to study the catalyst performance in the partial hydrogenation of sunflower oil. Results from various characterisation studies showed that increasing ultrasonic intensity caused a higher degree of hydroxycarbonate erosion and suppressed the formation of Ni silicates and silica support, which improved Ni dispersion, BET surface area and catalyst reducibility. Growth of silica clusters on the catalyst aggregates were observed in the absence of ultrasonication, which explained the higher silica and nickel silicate content on the outer surface of the catalyst particle. Application of ultrasound also altered the electron density of the Ni species, which led to higher activity and enhanced product selectivity for sonicated catalysts. The catalyst synthesised with ultrasonic intensity of 20.78 Wcm^-2 achieved 22.6% increase in hydrogenation activity, along with 28.5% decrease in trans-C18:1 yield at IV = 70, thus supporting the feasibility of such technique.