Photothermal steam reforming (PTR) has emerged as an attractive approach for catalytic tar removal, due to the excitation of the photothermal synergistic effect. However, the role of oxygen species in PTR is still unclear. In this paper, the effect of alkaline earth metals (Ca and Sr) A-site-substitution on perovskite LaNi 0.6 Mn 0.5 O 3 was investigated to reveal the role of oxygen species in PTR. The substitution of alkaline earth metals into perovskite lattice affected the dispersion of nickel and significantly adjusted the active oxygen species content on the catalyst surface. Oxygen species are crucial to the carbon deposition behavior of catalysts in PTR. La 0.7 Ca 0.3 Ni 0.6 Mn 0.5 O 3 was rich in reactive oxygen species, which effectively inhibited the deposition and graphitization of coke, resulting in its good coke resistance and catalytic stability in PTR. Ultraviolet–visible light (UV–vis) supported the formation of oxygen vacancies and the dissociation of H 2 O to hydroxyl radicals through the photochemical reaction, which ultimately increased the surface adsorbed oxygen contents. Meanwhile, UV–vis promoted the migration and reaction of lattice oxygen. The photoactivation of oxygen species by UV–vis effectively enriched active oxygen species and improved the coke resistance, which resulted in enhanced catalytic stability of PTR at low-temperature.
A-site doping with Ca 2+ , Sr 2+ for the cobalt-free BaFeO 3-δ -based cathode materials for proton-conducting ceramic fuel cells (PCFCs) is studied. The composite Ba 0·8 Ca 0·2 FeO 3-δ (BCF0.2)-BaZr 0.1 Ce 0·7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) and Ba 0·8 Sr 0·2 FeO 3-δ (BSF0.2)-BZCYYb electrode show polarization resistance (R p ) of 0.156 Ω cm 2 and 0.308 Ω cm 2 at 700 °C, respectively. It is found that the Ca or Sr doping not only benefits oxygen vacancy formation and ion migration but also optimizes the surface oxygen reduction reaction (ORR) process. The density functional theory (DFT) calculations show that the Gibbs energies of *OOH and *OH intermediates are decreased, indicating an enhanced surface ORR. The PCFC with BCF0.2-BZCYYb composite cathode achieves the maximum power density of 299.75 mW cm −2 at 700 °C and shows good stability at 650 °C for 65 h under a constant voltage of 0.75 V. These findings suggest that the BCF0.2-BZCYYb has the potential to serve as cobalt-free cathode materials for PCFCs.
危险品化学品经营许可证（带存储）