CO2 Hydrogenation to Methane over Ni-Catalysts: The Effect of Support and Vanadia Promoting

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods are developed to target the “closed carbon cycle”. The catalysts supported on different metal oxides were characterized by XRD, XPS, Raman, UV-Vis, temperature-programmed techniques; then, they were tested in CO2 hydrogenation at 1 bar. Moreover, the V2O5 promotion was studied for Ni/Al2O3 catalyst. The precisely designed hydrotalcite-derived catalyst and vanadia-promoted Ni-catalysts deliver exceptional conversions for the studied processes, presenting high durability and selectivity, outperforming the best-known catalysts. The equilibrium conversion was reached at temperatures around 623 K, with the primary product of reaction CH4 (>97% CH4 yield). Although the Ni loading in hydrotalcite-derived NiWP is lower by more than 40%, compared to reference NiR catalyst and available commercial samples, the activity increases for this sample, reaching almost equilibrium values (GHSV = 1.2 × 104 h–1, 1 atm, and 293 K).

Ceria-Based Materials in Hydrogenation and Reforming Reactions for CO2 Valorization

Reducing greenhouse emissions is of vital importance to tackle the climate changes and to decrease the carbon footprint of modern societies. Today there are several technologies that can be applied for this goal and especially there is a growing interest in all the processes dedicated to manage CO2 emissions. CO2 can be captured, stored or reused as carbon source to produce chemicals and fuels through catalytic technologies. This study reviews the use of ceria based catalysts in some important CO2 valorization processes such as the methanation reaction and methane dry-reforming. We analyzed the state of the art with the aim of highlighting the distinctive role of ceria in these reactions. The presence of cerium based oxides generally allows to obtain a strong metal-support interaction with beneficial effects on the dispersion of active metal phases, on the selectivity and durability of the catalysts. Moreover, it introduces different functionalities such as redox and acid-base centers offering versatility of approaches in designing and engineering more powerful formulations for the catalytic valorization of CO2 to fuels.

Nanoalloy Materials for Chemical Catalysis

Nanoalloys (NAs), which are distinctly different from bulk alloys or single metals, take on intrinsic features including tunable components and ratios, variable constructions, reconfigurable electronic structures, and optimizable performances, which endow NAs with fascinating prospects in the catalysis field. Here, the focus is on NA materials for chemical catalysis (except photocatalysis or electrocatalysis). In terms of composition, NA systems are divided into three groups, noble metal, base metal, and noble/base metal mixed NAs. Their design and fabrication for the optimization of catalytic performance are systematically summarized. Additionally, the correlations between the composition/structure and catalytic properties are also mentioned. Lastly, the challenges faced in current research are discussed, and further pathways toward their development are suggested.

Selective hydrogenation of unsaturated aldehydes over Pt nanoparticles promoted by the cooperation of steric and electronic effects

The selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols can reach high selectivity and activity at room temperature using Pt nanoparticles immobilized on a non-porous Al₂O₃ support stabilized by aspartic acid.

Sintering resistant Ni nanoparticles exclusively confined within SiO2 nanotubes for CH4 dry reforming

Ni nanoparticles are exclusively confined within the channels of SiO₂ nanotubes (NTs) using the Ni phyllosilicate@SiO₂ nanocomposite as a precursor where Ni phyllosilicate will in situ decompose into Ni nanoparticles within SiO₂ shell NTs, exhibiting good sintering and carbon resistance for CO₂ reforming of CH₄ reaction.