CO2 methanation over Ni/Al2O3-ZrO2 catalysts: Optimizing metal-oxide interfaces by calcinating-induced phase transformation of support

Dual-Element Modulation Excitation XAS to Probe the Redox Surface Chemistry of a Ni–Fe Dry Reforming Catalyst

“…A second contribution to enhanced CO 2 activation originates from material restructuring during redox cycling; this results in oxidic Fe formation, which provides additional CO 2 -activating interfaces with Ni. Such metal–oxide interfaces, either at the metal–support interface or at nanoparticle decorations, have been recognized to play an important role in the activation of CO 2 for Ni-based CO 2 methanation catalysts. ,− Therefore, their appearance under the present CO 2 /H 2 modulations is plausible. Their formation occurs within the transient regime of the MEXAS experiments, as indicated by the Fe K edge MCR-ALS (Figure B), and also in the CO 2 -rich regimes of the modulation, since PSD analysis (Figure ) indicates Fe 2+ formation prior to Fe 3+ .…”

Nitric Acid-Pretreated Natural Halloysite Nanotubes as Ni Nanoparticle Catalyst Supports for CO2 Methanation

“…To analyze the chemical state of Ni on the catalyst surface, XPS characterization was carried out, and the results are shown in Figure d. The binding energies centered at 852.8 eV (Ni 2p 3/2 ) and 870.3 eV (Ni 2p 1/2 ) can be ascribed to Ni 0 , while the peaks around 856.1 and 873.5 eV can correspond to Ni 2p 3/2 and Ni 2p 1/2 orbitals for Ni 2+ , respectively, due to the oxidization of metal Ni. , Additionally, the peaks located at 861.4 and 880.1 eV can be attributed to the satellite peaks of Ni 2+ . As listed in Table S2, Ni(30%)/HNTs-8AC presents a larger ratio of Ni 0 /(Ni 0 +Ni 2+ ) among all the catalysts, which can provide more active sites for CO 2 methanation …”

“…59,60 Additionally, the peaks located at 861.4 and 880.1 eV can be attributed to the satellite peaks of Ni 2+ . 61 As listed in Table S2, Ni(30%)/HNTs-8AC presents a larger ratio of Ni 0 /(Ni 0 +Ni 2+ ) among all the catalysts, which can provide more active sites for CO 2 methanation. 53 The activity test results of Ni(x%)/HNTs-8AC show that increasing Ni loading can effectively improve the catalytic performance, especially at low temperatures of 300 and 350 °C (Figure 6e,f), considering that there are more reducible Ni species on the catalyst surface, as supported by H 2 -TPR results.…”

Effect of catalyst properties on selectivity in CO2 methanation with coupling pathway of RWGS and CO methanation

“…The loading of La–Ni–O x and La–Ce–Ni–O x on an AZ600 support (Al 2 O 3 –ZrO 2 composite oxide, as prepared in our previous work, 28 denoted as AZ in this work) was performed according to citrate complexation combined with the impregnation method. High-purity reagent-grade Ni(NO 3 ) 3 ·6H 2 O, Ce(NO 3 ) 3 ·6H 2 O, and La(NO 3 ) 3 ·6H 2 O were used as metal precursors.…”