Exploring the Interfacial Hydrogen Transfer between Pt and the Siliceous Framework and Its Promotional Effect on the
Hongbing Wang1, Yifei Yang1, Yida Zhou2
1Institute of Materials, China Academy of Engineering Physics, Jiangyou 621908, China.
Abstract:
Interfacial hydrogen transfer between metal particles and catalyst supports is a ubiquitous phenomenon in heterogeneous catalysis, and this occurrence on reducible supports has been established, yet controversies remain about how hydrogen transfer can take place on nonreducible supports, such as silica. Herein, highly dispersed Pt clusters supported on a series of porous silica materials with zeolitic or/and amorphous frameworks were prepared to interrogate the nature of hydrogen transfer and its promotional effect on H2-HDO isotope catalytic exchange. The formation of zeolitic frameworks upon these porous silica supports by hydrothermal crystallization greatly promotes the interfacial hydrogen bidirectional migration between metal clusters and supports. Benefiting from this transfer effect, the isotope exchange rate is enhanced by 10 times compared to that on the amorphous counterpart (e.g., Pt/SBA-15). In situ spectroscopic and theoretical studies suggest that the defective silanols formed within the zeolite framework serve as the reactive sites to bind HDO or H2O by hydrogen bonds. Under the electrostatic attraction interaction, the D of hydrogen-bonded HDO scrambles to the Pt site and the dissociated H on Pt simultaneously spills back to the electronegative oxygen atom of adsorbed water to attain H-D isotope exchange with an energy barrier of 0.43 eV. The reverse spillover D on Pt combines with the other H on Pt to form HD in the effluent. We anticipate that these findings are able to improve our understanding of hydrogen transfer between metal and silica supports and favor the catalyst design for the hydrogen-involving reaction.
More Related Videos
10:52Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
Published on: April 12, 2019
11:02Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica
Published on: July 9, 2015
Related Concept Videos
02:13Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
02:50Catalysis
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...