Wang Xintao,Zhong Jianyi,Li Zhanggui,Xiang Jiali,Hou Bingxue,Tan Zanxiong,Liu Lisha,Wang Cheng Cheng
The development of high-performance and chromium-tolerant stable hierarchical cathodes is crucial for practical applications of solid oxide fuel cells (SOFCs). This work presents a synergistic strategy to manufacture hierarchical cathodes, focusing on optimizing microstructural and electrochemical properties. By integrating advanced fabrication techniques, including nanostructuring and surface engineering, we achieved a significant enhancement in high entropy double perovskite cathode. The electrochemical activities and chromium tolerance of BaO impregnated on (La 0.2 Pr 0.2 Sm 0.2 Gd 0.2 Nd 0.2 )Ba 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5 (LPSGNBSCF) high-entropy double perovskite cathodes in SOFCs were investigated in this study. Here, an optimum coated amount of BaO-LPSGNBSCF-0.15 mol/L electrode exhibited smaller electrode polarization resistance ( R p ) of 0.22 Ω cm 2 than pure LPSGNBSCF electrode with R p of 0.5 Ω cm 2 operating at 800 °C in the presence of Cr 2 O 3 for 100 h. The synergistic catalyst coating of BaO-LPSGNBSCF-0.15 M could lead to less Cr deposition and SrCrO 4 formation on LPSGNBSCF after exposure to Cr 2 O 3 . Moreover, the cell delivered the maximum power density of 985.9 mW/cm 2 at 800 °C, higher than 803.1 mW/cm 2 of bare LPSGNBSCF single cell and showed good stability with 100 h in short-term test. This work elucidated a rational design of efficient and durable high-entropy-based chromium tolerant cathode for SOFCs.
An efficient and facile water dissociation process plays a crucial role in enhancing the activity of alkaline hydrogen evolution reaction (HER). Considering the intricate influence between interfacial water and intermediates in typical catalytic systems, meticulously engineered catalysts should be developed by modulating electron configurations and optimizing surface chemical bonds. Here, a high-entropy double perovskite (HEDP) electrocatalyst La 2 (Co 1/6 Ni 1/6 Mg 1/6 Zn 1/6 Na 1/6 Li 1/6 )RuO 6 , achieving a reduced overpotential of 40.7 mV at 10 mA cm −2 and maintaining exemplary stability over 82 h in a 1 m KOH electrolyte is reported. Advanced spectral characterization and first-principles calculations elucidate the electron transfer from Ru to Co and Ni positions, facilitated by alkali metal-induced super-exchange interaction in high-entropy crystals. This significantly optimizes hydrogen adsorption energy and lowers the water decomposition barrier. Concurrently, the super-exchange interaction enhances orbital hybridization and narrows the bandgap, thus improving catalytic efficiency and adsorption capacity while mitigating hysteresis-driven proton transfer. The high-entropy framework also ensures structural stability and longevity in alkaline environments. The work provides further insights into the formation mechanisms of HEDP and offers guidelines for discovering advanced, efficient hydrogen evolution catalysts through super-exchange interaction.
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