Ultra‐Low Loading Pt/CeO₂ Catalysts: Ceria Facet Effect Affords Improved Pairwise Selectivity for Parahydrogen Enhanced NMR Spectroscopy

Abstract

Oxide supports with well‐defined shapes enable investigations on the effects of surface structure on metal–support interactions and correlations to catalytic activity and selectivity. Here, a modified atomic layer deposition technique was developed to achieve ultra‐low loadings (8–16 ppm) of Pt on shaped ceria nanocrystals. Using octahedra and cubes, which expose exclusively (111) and (100) surfaces, respectively, the effect of CeO2 surface facet on Pt‐CeO2 interactions under reducing conditions was revealed. Strong electronic interactions result in electron‐deficient Pt species on CeO2 (111) after reduction, which increased the stability of the atomically dispersed Pt. This afforded significantly higher NMR signal enhancement in parahydrogen‐induced polarization experiments compared with the electron‐rich platinum on CeO2 (100), and a factor of two higher pairwise selectivity (6.1 %) in the hydrogenation of propene than any previously reported monometallic heterogeneous Pt catalyst.

Noble Metal Single‐Atom Catalysts for the Catalytic Oxidation of Volatile Organic Compounds

“…Therefore, new synthesis approaches are expected to be developed to enhance the amount of surface active oxygen species on the SAC. (4) Solid catalysts exposing different crystal planes have been reported to present different catalytic performances, [32h] whereas metal single atoms supported on the different planes of a faceted oxide have different coordination environments, exhibiting different catalytic properties, as was recently reported for a Pt 1 /CeO 2 SAC [57] . Therefore, further studies are suggested to investigate metal SACs supported on reducible supports exposing different planes, especially for low‐temperature oxidation of VOCs.…”

“…(4) Solid catalysts exposing different crystal planes have been reported to present different catalytic performances, [32h] whereas metal single atoms supported on the different planes of a faceted oxide have different coordination environments, exhibiting different catalytic properties, as was recently reported for a Pt 1 /CeO 2 SAC. [57] Therefore, further studies are suggested to investigate metal SACs supported on reducible supports exposing different planes, especially for lowtemperature oxidation of VOCs. (5) When testing catalyst performances in VOCs oxidation, most studies have focused on the oxidation of a VOC molecule.…”