Solid oxide electrolysis cells (SOECs) have attracted increasing attention as a promising device for the electrochemical CO2 reduction reaction (CO2RR) due to their high efficiency and fast kinetics. Exploring active cathode catalysts for the CO2RR is highly desirable for the research and development of SOECs. Herein, in situ exsolved FeNi3 nanoparticles on a Sr2Fe1.35Mo0.45Ni0.2O6−δ (SFMN) double perovskite substrate (FeNi3@SFMN) is developed to efficiently catalyze the CO2RR in SOECs. The SOEC with the FeNi3@SFMN–GDC (Gd0.2Ce0.8O1.9) cathode shows a current density of 0.934 A cm−2 at 1.6 V and 800 °C, as well as high stability and no coke deposition for 40 h at 1.2 V. CO2-temperature programmed desorption and quasi in situ Fourier-transform infrared spectroscopy measurements verify the intensive adsorption of CO2 on the FeNi3@SFMN–GDC cathode. Distribution of relaxation time analysis combined with density functional theory calculations discloses the stimulative activation of CO2 at the interface between the exsolved FeNi3 nanoparticles and the SFMN substrate with abundant oxygen vacancies, which improves the CO2RR performance at the FeNi3@SFMN–GDC cathode.

In situ exsolved FeNi3 nanoparticles on nickel doped Sr2Fe1.5Mo0.5O6−δ perovskite for efficient electrochemical CO2 reduction reaction

Bi and Sn co-doped perovskite BaFe0.8−XSn0.2BiXO3−δ materials have been designed and characterized as a series of new cathodes for proton-conducting solid oxide fuel cells (SOFCs), providing a new life for the traditional BaFeO3-based cathodes. Proton uptake of the cathode increases significantly with bismuth-doping, favoring the application of Bi and Sn co-doped perovskite BaFe0.8−XSn0.2BiXO3−δ materials in proton-conducting SOFCs. The density functional theory (DFT) calculation also suggests that the bismuth-doping leads to a dramatic increase of hydration energy and acceleration of proton migration for the BFS material. The XPS results show that the oxygen reduction reaction (ORR) activity of the cathode is enhanced after bismuth is added, which is consistent with the experimental results of the power density of the single cell. The maximum power density of the single cells with the structure of NiO-BaZr0.1Ce0.7Y0.2O3−δ|BaZr0.1Ce0.7Y0.2O3−δ| BaFe0.5Sn0.2Bi0.3O3−δ (BFSBi0.3) reached 1277 mW cm−2 at 700 °C, which is a record-high performance for proton-conducting SOFCs using cobalt-free cathodes, compared with previous reports. The outstanding fuel cell performance and good long term stability indicate that bismuth-doping is an effective way of promoting proton-conduction in traditional cathodes. This study opens a new door to the design of high performance cathodes for proton-conducting SOFCs.

A novel cobalt-free cathode with triple-conduction for proton-conducting solid oxide fuel cells with unprecedented performance

XPS study on La0.67Ca0.33Mn1−xCoxO3 compounds

Perovskites type oxides La1−xCaxRu1−xNixO3 were synthesized by the citrate sol–gel method. Characterization was carried out underlying the modification of metal catalysts by promoters by total or partial substitution of A- and B-site cations. The influence of Ru partial substitution by Ni in the LaRuO3 structure and of La by Ca on LaRu0.8Ni0.2O3 was also investigated in the dry and combine reforming of methane. All perovskites series, showed a well-defined perovskite structure with surface areas between 2 and 17 m2/g. After reduction Ru(Ni) crystallites size in the order of 10–15 nm were produced. An oxygen deficiency was shown by most perovskites. Substitution of La by Ca of smaller ionic radium decreases the stability of the perovskites and lowers their reduction temperature. Among the calcium series, La0.8Ca0.2Ru0.8Ni0.2O3, proved to be the most active precursor catalyst with the highest selectivity to syngas. Correlation between the effect of partial or total substitution of La by Ca as A-site cation of the precursor perovskite, the catalytic activity and stability of in situ formed Ru(Ni) particles was established.

Perovskites as catalysts precursors: synthesis and characterization

Combined methane reforming in presence of CO2 and O2 over LaFe1−xCoxO3 mixed-oxide perovskites as catalysts precursors

X-ray photoelectron spectroscopy investigation on chemical states of oxygen on surfaces of mixed electronic–ionic conducting La0.6Sr0.4Co1−yFeyO3 ceramics

Run-zhang Yuan

Papers

X-ray photoelectron spectroscopy investigation on chemical states of oxygen on surfaces of mixed electronic–ionic conducting La0.6Sr0.4Co1−yFeyO3 ceramics