The PtCo 3 nanoparticles (NPs of 2–5 nm) were synthesized by the organic phase reduction method and the PtCo 3 -C samples were obtained by physically loading the bimetallic NPs on the carbon black. The catalytic activity and stability of PtCo 3 -C for toluene oxidation under different reaction conditions were studied. The PtCo 3 -C can completely oxidize and decompose 1000 ppm toluene at 238 ℃ for at least 120 h, which has excellent low-temperature catalytic activity and thermal stability. In addition, PtCo 3 -C displays a great water and CO 2 resistance when 3.5 to 20 vol% water vapor (at least 110 h) or 3.5 to 10 vol% CO 2 (at least 60 h) is introduced into the reaction gas at 238 ℃. Moreover, the adsorption energy of toluene (−73.68 kJ mol −1 ) is much higher than that of water (−24.5 kJ mol −1 ) and CO 2 (−37.56 kJ mol −1 ), which were calculated by the density functional theory (DFT). Furthermore, catalytic mechanism of the oxidation of toluene over the PtCo 3 -C catalyst was also proposed. This study presents a good catalyst candidate obtaining high catalytic activity and stability with great water and CO 2 resistance for the removal of toluene.
The cathodes of solid oxide fuel cells (SOFCs) often suffer from detrimental cation segregations and associated impurities poisoning, leading to insufficient electroactivity and poor stability. Here we developed a medium-entropy double perovskite GdBa(Co 1.2 Mn 0.2 Fe 0.2 Ni 0.2 Cu 0.2 )O 5-δ (ME-GBCO) for promising SOFC cathode. The increased configuration entropy can effectively tailor the surface composition with in situ formed active BaCoO 3-δ (BCO) species, rather than inert and deleterious BaO x segregation on parent GdBaCo 2 O 5-δ (GBCO) surface. Accordingly, the layered ME-GBCO cathode with beneficial surface reconstruction exhibited not only high oxygen reduction activity but excellent durability against CO 2 impurity, enabling it a very attractive cathode for intermediate temperature SOFCs (IT-SOFCs). Our study provides a new idea for development of efficient and durable cathodes via configurational entropy induced rational surface reconstruction.
Peng Qiu,Ao Wang,Haoyu Zheng,Lichao Jia,Bo Chi,Jian Pu,Jian Li
LaCoO 3-δ (LC)-coated Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) cathode is fabricated by the solution impregnation method and promoted electrochemical performance is obtained. After being coated by LC shell, the polarization resistance can be as low as 0.197 Ω cm 2 and the peak power density is 0.243 W cm −2 at the operating temperature of 600 °C. The excellent CO 2 resistance of LC-coated BSCF cathode is verified by the CO 2 -poisoning test. Even in the operating atmosphere with high CO 2 concentration, the polarization resistance change of LC-coated BSCF cathode is much smaller than that of the blank BSCF cathode. By long-term test of single cells, the remarkable electrochemical performance stability of LC-coated BSCF cathode is shown. The promoted electrochemical performance, excellent CO 2 resistance and remarkable long-term stability make LC-coated BSCF cathode promising for intermediate temperature solid oxide fuel cells.
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