Improved Water–Gas Shift Performance of Au/NiAl LDHs Nanostructured Catalysts via CeO2 Addition

Abstract

Supported gold on co-precipitated nanosized NiAl layered double hydroxides (LDHs) was studied as an effective catalyst for medium-temperature water–gas shift (WGS) reaction, an industrial catalytic process traditionally applied for the reduction in the amount of CO in the synthesis gas and production of pure hydrogen. The motivation of the present study was to improve the performance of the Au/NiAl catalyst via modification by CeO2. An innovative approach for the direct deposition of ceria (1, 3 or 5 wt.%) on NiAl-LDH, based on the precipitation of Ce3+ ions with 1M NaOH, was developed. The proposed method allows us to obtain the CeO2 phase and to preserve the NiAl layered structure by avoiding the calcination treatment. The synthesis of Au-containing samples was performed through the deposition–precipitation method. The as-prepared and WGS-tested samples were characterized by X-ray powder diffraction, N2-physisorption and X-ray photoelectron spectroscopy in order to clarify the effects of Au and CeO2 loading on the structure, phase composition, textural and electronic properties and activity of the catalysts. The reduction behavior of the studied samples was evaluated by temperature-programmed reduction. The WGS performance of Au/NiAl catalysts was significantly affected by the addition of CeO2. A favorable role of ceria was revealed by comparison of CO conversion degree at 220 °C reached by 3 wt.% CeO2-modified and ceria-free Au/NiAl samples (98.8 and 83.4%, respectively). It can be stated that tuning the properties of Au/NiAl LDH via CeO2 addition offers catalysts with possibilities for practical application owing to innovative synthesis and improved WGS performance.

Facet-dependent activity of shape-controlled TiO2 supported Au nanoparticles for the water–gas shift reaction

“…33 The ratios between the peak areas of O − and O 2− are listed in Table S2, † which can be related to the concentration of O v . Since O v can assist the dissociation of H 2 O and production of active hydroxyl groups, 34,35 the concentrations of O v of Au/TiO 2 catalysts are also consistent with their WGS activities. The results of Au 4f and Ti 2p have also been analyzed and the results are shown in Fig.…”

Preparation of a Water–Gas Shift Database to Evaluate the Performance of Noble Metal Catalysts Using Theory-Guided Machine Learning

“…In Table , we list all 32 preparation methods with the references in which these methods are utilized. − This number of preparation methods is much higher than the 12 preparation methods reported in the early database prepared by Odabaşı et al 12 preparation methods (index 1–12 in Table ) such as wet impregnation, coprecipitation, deposition precipitation, and incipient to wetness impregnation method can be found in both databases; however, 19 methods (index 13–31 in Table ) such as hydrothermal and liquid-phase reductive deposition can be found in our database only. The significant increase in preparation methods suggests a growing research focus on catalyst design innovation.…”

The Route from Green H2 Production through Bioethanol Reforming to CO2 Catalytic Conversion: A Review

“…The performance was attributed to the dual role of magnesium, which contributes to improving the Ni 2+ ion dispersion and reducing the surface acidity of Ni-Mg-Al metal oxide formed during the reaction at high temperatures. Moreover, the addition of ceria to gold supported on nanosized NiAl layered double hydroxides showed improved performance in the WGS reaction because it resulted in the highest dispersion of gold particles [84]. CeO 2 -ZnO porous nanorods have been used to control the size and to prevent the sintering of Au nanoparticles; moreover, the presence of zinc oxide prevents the formation of undesired side products such as CH 4 and CH 3 OH [85].…”