Pt/CePO₄catalysts for the WGS reaction: influence of the water-supplier role of the support on the catalytic performance

Abstract

CePO4 supports enhance the WGS catalytic performance of Pt catalysts through the supplying of water, which depends on the crystallographic structure of the support.

Evaluation of the Oxygen Mobility in CePO4-Supported Catalysts: Mechanistic Implications on the Water–Gas Shift Reaction

“…The presence of oxygen vacancies associated with the CeO 2 redox properties, that is, the presence of the Ce 3+ /Ce 4+ redox pair, has been demonstrated to play a substantial role regarding the oxygen mobility in this solid, which influences the behavior and reaction mechanism of CeO 2 -based catalysts during the WGS reaction. 4,28,29 In our case, the low oxygen mobility is explained by the great stability of the Ce 3+ ion in both CePO 4 structures 27 previously demonstrated by X-ray photoelectron spectroscopy, 8,30 thus excluding the redox role in these supports.…”

“…CePO 4 supports were prepared by a hydrothermal method previously described. 8 The obtained materials were calcined in air at two different temperatures: 400 °C, to obtain the rhabdophane-type phase of CePO 4 (CeP400) and 600 °C, to obtain the monazite-type phase (CeP600). Pt catalysts with a nominal content of 2 wt % were prepared by wet impregnation and calcined at 350 °C.…”

“…3,4 However, in the last few years, some studies have been devoted to the use of phosphate-type solids as WGS catalytic supports. 5−7 In a previous study, 8 we reported the use of Pt/CePO 4 catalysts as highly active and selective catalytic systems for the WGS reaction. CePO 4 can present two different crystal structures: the hexagonal (rhabdophane-type) phase, which contains structural channels able to hold water molecules, and the monoclinic (monazite-type) phase in which the vanishing of the structural channels takes place.…”

Ligand-Functionalization-Controlled Activity of Metal–Organic Framework-Encapsulated Pt Nanocatalyst toward Activation of Water

“…To address the reactivity of H 2 O absorbed in MOFs, we focused on the water–gas shift (WGS) reaction (H 2 O + CO → H 2 + CO 2 ), in which the activation of H 2 O is the rate-determining step of the reaction . One of the representative catalysts in the WGS reaction is the Pt nanocrystal (NC), , and we hence covered Pt NCs with UiO-66 (Pt@UiO-66) to control the reactivity of H 2 O by the pores. In this report, we demonstrate systematic control of the WGS reaction activity of Pt@UiO-66 by changing the functional group of the BDC ligand of UiO-66.…”

Tuning the structure of cerium phosphate nanorods

“…Rare-earth orthophosphates (LnPO 4 ) are an important family of functional materials with uses in luminescence 1-3 catalysis 4,5 , heat-resistance 6 , cosmetics 7 , radioactive waste storage 8 and electrochemistry. 9 They often have multiple crystal forms, cerium phosphate for example has two well documented crystal structures: rhabdophane (hexagonal) and monazite (monoclinic) with the hexagonal form usually including structural water, (CePO 4 .nH 2 O ) and formed at low temperatures while the monoclinic form is anhydrous and formed at high temperatures.…”