A Common Single-Site Pt(II)–O(OH)_x– Species Stabilized by Sodium on “Active” and “Inert” Supports Catalyzes the Water-Gas Shift Reaction

Abstract

While it has long been known that different types of support oxides have different capabilities to anchor metals and thus tailor the catalytic behavior, it is not always clear whether the support is a mere carrier of the active metal site, itself not participating directly in the reaction pathway. We report that catalytically similar single-atom-centric Pt sites are formed by binding to sodium ions through -O ligands, the ensemble being equally effective on supports as diverse as TiO2, L-zeolites, and mesoporous silica MCM-41. Loading of 0.5 wt % Pt on all of these supports preserves the Pt in atomic dispersion as Pt(II), and the Pt-O(OH)x- species catalyzes the water-gas shift reaction from ∼120 to 400 °C. Since the effect of the support is "indirect," these findings pave the way for the use of a variety of earth-abundant supports as carriers of atomically dispersed platinum for applications in catalytic fuel-gas processing.

Single‐Atom to Single‐Atom Grafting of Pt1 onto FeN4 Center: Pt1@FeNC Multifunctional Electrocatalyst with Significantly Enhanced Properties

“…The oxidation state of Pt is between +2 and +4 and very close to +4, indicating that the Pt 4+ ions were slightly reduced after being grafted onto the FeNC. [29,30] As previously reported, the Fe center in FeN x moiety would adsorb an oxygen molecule from the air, which would oxidize Fe and be negatively charged. [31,32] X-ray absorption spectroscopy, including X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy, was performed to further investigate the local atomic configuration around iron and platinum in Pt 1 @FeNC.…”

Potential‐Cycling Synthesis of Single Platinum Atoms for Efficient Hydrogen Evolution in Neutral Media

“…This result is consistent with the X‐ray diffraction (XRD) pattern of a centimeter‐scale piece of PtSA‐NT‐NF (Figure 3 a), which contains the signals of not Pt but Ni(OH) 2 , CoP, and Co 2 P crystal grains. Moreover, as shown in Figure 3 b, the X‐ray photoelectron spectrum (XPS) of commercial Pt/C containing Pt nanoparticles displays two Pt 4f peaks at 71.6 and 74.9 eV, indicative of Pt 0 (Refs 4b, 13c, 19). In contrast, the two Pt 4f peaks of a centimeter‐scale piece of PtSA‐NT‐NF are located at 72.3 and 75.6 eV, which are characteristic of Pt 2+ (Refs.…”

“…In contrast, the two Pt 4f peaks of a centimeter‐scale piece of PtSA‐NT‐NF are located at 72.3 and 75.6 eV, which are characteristic of Pt 2+ (Refs. 4b, 13c, 19). The lack of a detectable Pt 0 signal implies that not Pt crystal grains but only single Pt atoms exist in PtSA‐NT‐NF, conforming to the absence of Pt crystal grain signals in the XRD and the electron diffraction patterns.…”

Tracking Rh Atoms in Zeolite HY: First Steps of Metal Cluster Formation and Influence of Metal Nuclearity on Catalysis of Ethylene Hydrogenation and Ethylene Dimerization

“…[7][8][9][10][11] A step toward increasing complexity of such catalysts involves the synthesis of pairs of metal centers on supports, and these offer prospects of new properties associated with the neighboring metal centers. There are still only a small number of catalysts in this class.…”