Highly Efficient La_xCe_1–xO_2–x/2 Nanorod-Supported Nickel Catalysts for CO Methanation: Effect of La Addition

Abstract

A group of ternary La x Ce1–x O2–x/2 nanorods with varying La/Ce ratios have been prepared by the hydrothermal strategy and further used to synthesize supported nickel catalysts for CO methanation. The optimal Ni/La0.15Ce0.85O1.925 catalyst showed remarkably improved activity and excellent resistance against coke formation compared with Ni/CeO2. The characterization results demonstrated that doping of La2O3 into CeO2 resulted in decreased grain size of Ni particles and increased Ni electron cloud density induced by the creation of more oxygen vacancies due to substituting La3+ for Ce4+, which were responsible for accelerating CO dissociation and eventually improved CO methanation activity. More importantly, the enhanced oxygen vacancies were helpful to improve the anticoking properties through eliminating the deposited carbon species. These studies shed light on the design of a catalyst with both outstanding activity at low temperatures and reliable stability at high temperatures for the CO methanation reaction.

Investigation on YSZ- and SiO2-Doped Mn-Fe Oxide Granules Based on Drop Technique for Thermochemical Energy Storage

“…In the XRD tests, many factors could result in the peak shift, such as the structure strain from the doping of a heterogeneous atom, the inhomogeneity and impurity in the sample, the morphological characteristics of the sample (powder, coating, and film), the conditions of the test instrument, etc. Generally, the peak shift would show a regular trend with heterogeneous atoms doping as the change in the cell volume because of the replacement of the host atom by the doped atom [33][34][35]. Therefore, the shifts of the characteristic peak in Figure 1a may not only be ascribed to the doping effects.…”