Spray-Dried Ni Catalysts with Tailored Properties for CO2 Methanation

Abstract

A catalyst production method that enables the independent tailoring of the structural properties of the catalyst, such as pore size, metal particle size, metal loading or surface area, allows to increase the efficiency of a catalytic process. Such tailoring can help to make the valorization of CO2 into synthetic fuels on Ni catalysts competitive to conventional fossil fuel production. In this work, a new spray-drying method was used to produce Ni catalysts supported on SiO2 and Al2O3 nanoparticles with tunable properties. The influence of the primary particle size of the support, different metal loadings, and heat treatments were applied to investigate the potential to tailor the properties of catalysts. The catalysts were examined with physical and chemical characterization methods, including X-ray diffraction, temperature-programmed reduction, and chemisorption. A temperature-scanning technique was applied to screen the catalysts for CO2 methanation. With the spray-drying method presented here, well-organized porous spherical nanoparticles of highly dispersed NiO nanoparticles supported on silica with tunable properties were produced and characterized. Moreover, the pore size, metal particle size, and metal loading can be controlled independently, which allows to produce catalyst particles with the desired properties. Ni/SiO2 catalysts with surface areas of up to 40 m2 g−1 with Ni crystals in the range of 4 nm were produced, which exhibited a high activity for the CO2 methanation.

Quantifying the Impact of Parametric Uncertainty on Automatic Mechanism Generation for CO2 Hydrogenation on Ni(111)

“…CO 2 methanation experiments were conducted with a 20 wt% Ni/SiO 2 catalyst produced with a spray-drying method as described in the work of Kreitz et al 74 A solution of colloidal SiO 2 nanoparticles with a primary particle size of 8 nm and Ni(NO 3 ) 2 was sprayed into a tubular furnace operated at 673 K using an atomizer to initiate a one-step calcination and assembly of Ni/SiO 2 nanoparticles. These nanoparticles were collected on a filter and heat-treated at 673 K for 3 h. The experiments were conducted with a Ni/SiO 2 catalyst because the acidic surface of the silica does not adsorb CO 2 8 and, therefore, does not participate in the methanation mechanism.…”

“…Ar was employed as an internal standard and to reduce thermal effects. A temperature-scanning experiment as described in Kreitz et al 74 was used to investigate the methanation reaction over the entire temperature range up to 773 K. During the temperature scan, the temperature was linearly raised with a rate of 20 K min –1 (see Table S3 for a summary). The product mole fraction was analyzed with a high temporal resolution using a mass spectrometer.…”

Quantifying the Impact of Parametric Uncertainty on Automatic Mechanism Generation for CO2 Hydrogenation on Ni(111)

“…to thermodynamic equilibrium that is reached in the experiment at temperatures beyond 700 K. An activation energy of 84 kJ mol −1 was determined, which is comparable to other Ni/SiO 2 catalysts. 10,64,87,88 Results from the microkinetic model generated by RMG with the reference settings shows a significantly lower activity at lower temperatures. CH 4 formation starts at 600 K and reaches the maximum rate at 700 K. The production of CO starts at a temperature of 650 K and directly reaches the equilibrium concentration.…”

“…This assumption is justified since no deviation between steady-state and transient results was observed in the experiments. 64 The parameters for the simulation are summarized in Table S3. As a simplification, no lateral interactions among the adsorbates were considered in the surface mechanism.…”

Cold Plasma Synthesis and Testing of NiOX-Based Thin-Film Catalysts for CO2 Methanation

“…It focused mainly on the dielectric barrier discharge (DBD) method used both in the process of initial catalyst formation and its final activation. It was found that such a procedure improved the catalytic properties and provided better anti-carbon deposit performance compared to the catalyst made only by thermal treatment [34][35][36][37][38]. It should be noted, however, that this is only a plasma treatment of "classically" produced catalysts.…”