Metal Phosphate-Supported Pt Catalysts for CO Oxidation

Abstract

Oxides (such as SiO2, TiO2, ZrO2, Al2O3, Fe2O3, CeO2) have often been used to prepare supported Pt catalysts for CO oxidation and other reactions, whereas metal phosphate-supported Pt catalysts for CO oxidation were rarely reported. Metal phosphates are a family of metal salts with high thermal stability and acid-base properties. Hydroxyapatite (Ca10(PO4)6(OH)2, denoted as Ca-P-O here) also has rich hydroxyls. Here we report a series of metal phosphate-supported Pt (Pt/M-P-O, M = Mg, Al, Ca, Fe, Co, Zn, La) catalysts for CO oxidation. Pt/Ca-P-O shows the highest activity. Relevant characterization was conducted using N2 adsorption-desorption, inductively coupled plasma (ICP) atomic emission spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), CO2 temperature-programmed desorption (CO2-TPD), X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). This work furnishes a new catalyst system for CO oxidation and other possible reactions.

High‐Performance Electrolytic Oxygen Evolution in Neutral Media Catalyzed by a Cobalt Phosphate Nanoarray

“…Figure a presents the X‐ray photoelectron spectroscopy (XPS) survey spectrum of Co‐Pi, indicating the presence of the elements Co, P, and O. Figure b shows the XPS spectrum in the O 1s region, and the binding energy (BE) at 530.8 eV is assigned to the central oxygen atoms in phosphate . The XPS spectrum in the P 2p region shows one sharp peak with BE of 133.0 eV corresponding to the core levels of central phosphorus atoms in phosphate species (Figure c) .…”

Pt/MOx/SiO2, Pt/MOx/TiO2, and Pt/MOx/Al2O3 Catalysts for CO Oxidation

“…It is known that enhanced basicity of support can enhance the activity of supported Pt catalysts for CO oxidation [48][49][50]. CO2 is a weak acid, and the temperature-programmed desorption of CO2 can indicate the basicity of catalysts.…”

“…The experimental conditions and procedures were reported previously [50]. Briefly, A catalyst (0.25 g) loaded into the reactor was pretreated in flowing 4% H2 (balance He) at 300 °C for 2 h, cooled down to room temperature, and the gas stream was switched to 1% CO (balance air, flow rate: 50 mL/min).…”

High‐Performance Electrolytic Oxygen Evolution in Neutral Media Catalyzed by a Cobalt Phosphate Nanoarray

“…Figure 2b shows the XPS spectrum in the O1sregion, and the binding energy (BE) at 530.8 eV is assigned to the central oxygen atoms in phosphate. [32] The XPS spectrum in the P2pr egion shows one sharp peak with BE of 133.0 eV corresponding to the core levels of central phosphorus atoms in phosphate species (Figure 2c). [33][34][35][36] In the XPS spectrum in the Co 2p region (Figure 2d), the BEs at 780.4 and 795.5 eV are assigned to the Co 2p 3/2 and Co 2p 1/2 , respectively,w ith the observation of one weak shoulder, suggesting the formation of Co with higher oxidation states (Co 3+ or Co 4+ ).…”