Sulfur-Tolerant Pt/CeO₂ Catalyst with Enhanced Oxygen Storage Capacity by Controlling the Pt Content for the Waste-to-Hydrogen Processes

Abstract

In the Pt/CeO2 catalyst, we found that the loading amount of Pt affects not only the dispersion of Pt but also the interaction between Pt and CeO2, specifically to the oxygen storage capacity. The interface between Pt and CeO2 has some special properties due to oxygen reverse spillover, which affects the oxygen storage capacity of the catalyst. The loading amount of Pt in the Pt/CeO2 catalyst was varied from 0.1 to 10.0 wt %, and the physicochemical properties were compared. The prepared samples were tested to the water–gas shift reaction in the waste-to-hydrogen process with the existence of 500 ppm of H2S to evaluate the sulfur tolerant catalytic performance. Among the samples, the 2.0% Pt/CeO2 catalyst showed the highest sulfur tolerance. Considering the catalytic reaction result and physicochemical properties, the sulfur tolerant catalytic activity can be mainly related to the oxygen storage capacity. From this result, we have concluded that the loading amount of Pt not only affects the dispersion of Pt0 but also affects the oxygen storage capacity of the catalyst.

The Effect of Precursor Concentration on the Crystallite Size of CeO2 to Enhance the Sulfur Resistance of Pt/CeO2 for Water Gas Shift

“…The quantity of this property by the Ce 3+ /Ce 4+ redox couple, which can be reversibly converted in the fluorite structure of CeO 2 , is called the oxygen storage capacity (OSC). In our previous studies, we confirmed that the oxygen reverse spillover caused by the interaction between the active metal Pt and the CeO 2 support and the excellent OSC of the CeO 2 support positively influenced the catalyst activity and sulfur tolerance in the WGS reaction [11][12][13][14][15]. It is noteworthy that various preparation parameters, such as reaction temperature, reaction time, precursor concentration, solvent, and pH, can be used to modify the characteristics of nanomaterials, including OSC, active metal dispersion, and redox properties.…”

“…Consequently, a catalyst with a higher OSC facilitates the acceleration of the redox mechanism governing the WGS reaction [16,36]. Furthermore, previous studies have identified OSC as a key factor in the sulfur resistance of catalysts in the WGS reaction [11,[13][14][15]. Specifically, sulfur adsorbed on the active metal of the Pt/CeO 2 catalyst can react with mobile oxygen derived from the CeO 2 support and subsequently be desorbed in the form of SO 2 [11].…”

“…Our research team previously developed a Pt catalyst supported on CeO 2 with sulfur tolerance for the WGS reaction using waste-derived synthesis gas [10][11][12][13][14][15]. The support plays a crucial role in determining the activity of the metal catalyst because it affects the electronic state of the active metal through the interaction between the active metal and the support.…”

Pt Nanoparticles and NiO Nanosheets on Ni Foam for Photothermal Degradation of Toluene

“…Another two sharp peaks at 71.0 and 74.4 eV are assigned to Pt 4f 7/2 and Pt 4f 5/2 , respectively, further confirming the existence of Pt species. 37,38 The remaining two small satellite peaks are related to the oxidation state of Pt, implying that Pt species grown on the NF existed mainly in the form of metallic Pt, and only a small proportion is in the oxidation state. 39 Notably, as the acid etching concentration increases, the peak area of positivelycharged Pt decreases gradually, which indicates that the acidic conditions can inhibit the adsorption of oxidized Pt on the surface of nickel foam so that the content of positively charged Pt decreases.…”

Hydrogen reverse spillover eliminating methanation over efficient Pt–Ni catalysts for the water–gas shift reaction

“…8,9 In dehydrogenation reactions, due to a concentration gradient of surface hydrogen atoms between generation sites of hydrogen atoms and recombination/desorption sites, "hydrogen reverse spillover" (HRS) is usually observed. 10,11 For example, Rh can recombine hydrogen atoms transferred from metal oxides by reverse spillover to enhance H 2 release over Rh/Fe 3 O 4 -Cr 2 O 3 for the HT-WGSR. 12 In the ammonia borane hydrolysis reaction over NiO/Al 2 O 3 /Pt, using reverse spillover, generated hydrogen atoms on NiO sites are transferred readily to Pt sites for H 2 desorption because the desorption barrier of H 2 is nearly free on Pt.…”