Escaping from Sabatier principle by introducing a confined environment: A case study on phenylacetylene semi-hydrogenation over nickel-based catalysts

• Published in: Journal of catalysis 2024-05, Vol.433, p.115465, Article 115465
• Main Authors: Guo, Jinqiu, Zhang, Hongbo
• Format: Article
• Language: English
• Subjects: Confined environment; Nickel-based catalysts; Phenylacetylene semi-hydrogenation; Regimes combination; Sabatier principle
• ISSN: 0021-9517
• DOI: 10.1016/j.jcat.2024.115465

Ni decorated NU-1000 nano-composites with various Ni loadings and MWCNTs confined Ni-NPs were applied to catalyze the semi-hydrogenation of phenylacetylene, which was selected as a probe reaction to systematically correlated the nano-size effect and the famous Sabatier Principle. TEM and in situ FTIR analysis as well as the reaction performance evaluation of phenylacetylene semi-hydrogenation were combined together to elucidate the factors affecting the parameters of each regime following the Sabatier principle. The results indicated that the inclination angle of the ascending regime (αAsc.) was greatly correlated to the Ni size (dVA, Ni; αAsc.∼[dVA, Ni]5∼0), while the degree of βDec. in the declining regime was almost independent of dVA, Ni (βDec.∼[dVA, Ni]0), and these two regimes were determined independently by reactant activation and product desorption. Additionally, the catalytic confinement effects could certainly modify the reactant activation and product desorption to some extent, thus promoting the length of the plateau regime (l). Sabatier principle is probably invalid within the channel. [Display omitted] •A trapezoid-shaped hydrogenation profile following Sabatier principle was established.•The inclination angle in the ascending regime was greatly affected by nickel sizes.•The angle in the declining regime was probably independent against the nickel sizes.•Sabatier principle was found to be invalid within the channel. The Sabatier principle defines the criteria for catalytic optimization with moderate binding energies between active component and support/gases; unfortunately, how the parameters within Sabatier profile determine the reaction performance is still lacking. Herein, using phenylacetylene semi-hydrogenation over nickel (Ni) as a probe, we show that styrene formation versus reaction temperature exhibits a trapezoid-shaped profile following Sabatier principle, with the inclination angle of ascending regime (αAsc.) greatly modified by Ni size (dVA, Ni; αAsc. ∼ [dVA, Ni]5∼0) while the declining regime (βDec.) was independent of dVA, Ni (βDec. ∼ [dVA, Ni]0) and was determined independently by reactant activation and product desorption. More interestingly, the length of the plateau region (l) was greatly promoted by confined environment. All these findings were determined from a systematic kinetic study of Ni-decorated NU-1000 and carbon nanotube reaction systems. This work would certainly deepen people’s understanding on selective hydrog