Self-Assembly Dual Active Site Nanocomposite Anode Ce0.6Mn0.3Fe0.1O2-δ/NiFe/MnOx for Electrooxidative Dehydrogenation of Ethane to Ethylene.

As the demand for ethylene grows continuously in industry, conversion of ethane to ethylene has become more and more important; however, it still faces fundamental challenges of low ethane conversion, low ethylene selectivity, overoxidation, and instability of catalysts. Electrooxidative dehydrogenation of ethane (EODHE) in a solid oxide electrolysis cell (SOEC) is an alternative process. Here, a multiphase oxide Ce0.6Mn0.3Fe0.1O2-δ-NiFe-MnOx has been fabricated by a self-assembly process and utilized as the SOEC anode material for EODHE. The highest ethane conversions reached 52.23% with 94.11% ethylene selectivity at the anode side and CO with 10.9 mL min-1 cm-2 at the cathode side, at 1.8 V at 700 °C. The remarkable electrooxidative performance of CMF-NiFe-MnOx is ascribed to the NiFe alloy and MnOx nanoparticles and improvement of the concentration of oxygen vacancies within the fluorite substrate, generating dual active sites for C2H6 adsorption, dehydrogenation, and selective transformation of hydrogen without overoxidizing the ethylene generated. Such a tailored strategy achieves no significant degradation observed after 120 h of operation and constitutes a promising basis for EODHE.

Enhanced Electrochemical Performance of the Fe-Based Layered Perovskite Oxygen Electrode for Reversible Solid Oxide Cells.

Reversible solid oxide cells (RSOCs) present a conceivable potential for addressing energy storage and conversion issues through realizing efficient cycles between fuels and electricity based on the reversible operation of the fuel cell (FC) mode and electrolysis cell (EC) mode. Reliable electrode materials with high electrochemical catalytic activity and sufficient durability are imperatively desired to stretch the talents of RSOCs. Herein, oxygen vacancy engineering is successfully implemented on the Fe-based layered perovskite by introducing Zr4+, which is demonstrated to greatly improve the pristine intrinsic performance, and a novel efficient and durable oxygen electrode material is synthesized. The substitution of Zr at the Fe site of PrBaFe2O5+δ (PBF) enables enlarging the lattice free volume and generating more oxygen vacancies. Simultaneously, the target material delivers more rapid oxygen surface exchange coefficients and bulk diffusion coefficients. The performance of both the FC mode and EC mode is greatly enhanced, exhibiting an FC peak power density (PPD) of 1.26 W cm-2 and an electrolysis current density of 2.21 A cm-2 of single button cells at 700 °C, respectively. The reversible operation is carried out for 70 h under representative conditions, that is, in air and 50% H2O + 50% H2 fuel. Eventually, the optimized material (PBFZr), mixed with Gd0.1Ce0.9O2, is applied as the composite oxygen electrode for the reversible tubular cell and presents excellent performance, achieving 4W and 5.8 A at 750 °C and the corresponding PPDs of 140 and 200 mW cm-2 at 700 and 750 °C, respectively. The enhanced performance verifies that PBFZr is a promising oxygen electrode material for the tubular RSOCs.

Pr-Doping Motivating the Phase Transformation of the BaFeO3-δ Perovskite as a High-Performance Solid Oxide Fuel Cell Cathode.

Intermediate temperature solid oxide fuel cells (IT-SOFCs) have been extensively studied due to high efficiency, cleanliness, and fuel flexibility. To develop highly active and stable IT-SOFCs for the practical application, preparing an efficient cathode is necessary to address the challenges such as poor catalytic activity and CO2 poisoning. Herein, an efficient optimized strategy for designing a high-performance cathode is demonstrated. By motivating the phase transformation of BaFeO3-δ perovskites, achieved by doping Pr at the B site, remarkably enhanced electrochemical activity and CO2 resistance are thus achieved. The appropriate content of Pr substitution at Fe sites increases the oxygen vacancy concentration of the material, promotes the reaction on the oxygen electrode, and shows excellent electrochemical performance and efficient catalytic activity. The improved reaction kinetics of the BaFe0.95Pr0.05O3-δ (BFP05) cathode is also reflected by a lower electrochemical impedance value (0.061 Ω·cm2 at 750 °C) and activation energy, which is attributed to high surface oxygen exchange and chemical bulk diffusion. The single cells with the BFP05 cathode achieve a peak power density of 798.7 mW·cm-2 at 750 °C and a stability over 50 h with no observed performance degradation in CO2-containing gas. In conclusion, these results represent a promising optimized strategy in developing electrode materials of IT-SOFCs.

Achieving Highly Efficient Carbon Dioxide Electrolysis by In Situ Construction of the Heterostructure.

The design of active cathode catalysts, with abundant active sites and outstanding catalytic activity for CO2 electroreduction, is important to promote the development of solid oxide electrolysis cells (SOECs). Herein, A-site-deficient perovskite oxide (La0.2Sr0.8)0.9Ti0.5Mn0.4Cu0.1O3-δ (LSTMC) is synthesized and studied as a promising cathode for SOECs. Cu nanoparticles can be rapidly and uniformly in situ-exsolved under reducing conditions. The heterostructure formed by the exsoluted Cu and LSTMC provides abundant active sites for the catalytic conversion of CO2 to CO. Combined with the remarkable oxygen-ion transport capacity of the LSTMC substrate, the specially designed Cu@LSTMC cathode exhibits a dramatically improved electrochemical performance. Furthermore, first-principles calculations proposed a mechanism for the adsorption and activation of CO2 by the heterostructure. Electrochemically, the Cu@LSTMC presents a high current density of 2.82 A cm-2 at 1.8 V and 800 °C, which is about 2.5 times higher than that of LSTM (1.09A cm-2).

Honeycombed Porous, Size-Matching Architecture for High-Performance Hybrid Direct Carbon Fuel Cell Anode.

Direct carbon fuel cells (DCFCs) demonstrate both superior electrical efficiency and fuel utilization compared to all other types of fuel cells, and it will be the most promising carbon utilization technology if the sluggish anode reaction kinetics that derives from the use of solid fuel can be addressed. Herein, the electrode morphology and fuel particle size are comprehensively considered to fabricate an efficient DCFC anode skeleton. A honeycombed and size-matching anode architecture with dual-scale porous structure is developed by water droplet templating, which demonstrates an efficient strategy to address the challenge of poor carbon reactivity and improve the electrochemical performance of DCFCs. Single cell with this designed anode framework demonstrates excellent performance, and the maximum power density is as high as 765 mW cm-2 at 800 °C when using the matching carbon fuel. The size-matching between carbon fuel and anode framework shows a remarkable effect on the improvement of mass-transfer processes at the anodes. The significant contribution of the difficult electrochemical oxidation of carbon to the output performance is also demonstrated. These results represent a promising structural design strategy in developing high-performing fuel cells.

Boosting the Electrochemical Performance of Fe-Based Layered Double Perovskite Cathodes by Zn2+ Doping for Solid Oxide Fuel Cells.

Mixed oxygen ionic and electronic conduction is a vital function for cathode materials of solid oxide fuel cells (SOFCs), ensuring high efficiency and low-temperature operation. However, Fe-based layered double perovskites, as a classical family of mixed oxygen ionic and electronic conducting (MIEC) oxides, are generally inactive toward the oxygen reduction reaction due to their intrinsic low electronic and oxygen-ion conductivity. Herein, Zn doping is presented as a novel pathway to improve the electrochemical performance of Fe-based layered double perovskite oxides in SOFC applications. The results demonstrate that the incorporation of Zn ions at Fe sites of the PrBaFe2O5+δ (PBF) lattice simultaneously regulates the concentration of holes and oxygen vacancies. Consequently, the oxygen surface exchange coefficient and oxygen-ion bulk diffusion coefficient of Zn-doped PBF are significantly tuned. The enhanced mixed oxygen ionic and electronic conduction is further confirmed by a lower polarization resistance of 0.0615 and 0.231 Ω·cm2 for PrBaFe1.9Zn0.1O5+δ (PBFZ0.1) and PBF, respectively, which is measured using symmetric cells at 750 °C. Moreover, the PBFZ0.1-based single cell demonstrates the highest output performance among the reported Fe-based layered double perovskite cathodes, rendering a peak power density of 1.06 W·cm-2 at 750 °C and outstanding stability over 240 h at 700 °C. The current work provides a highly effective strategy for designing cathode materials for next-generation SOFCs.

Enhanced Stability and Catalytic Activity on Layered Perovskite Anode for High-Performance Hybrid Direct Carbon Fuel Cells.

In this work, we investigate a novel A-site ordered layered perovskite oxide, (PrBa)0.95Fe1.8-xCuxNb0.2O5+δ (PBFCN), as an anode material for hybrid direct carbon fuel cells (HDCFCs). We study the effect of anode composition on the electrochemical performance of HDCFCs. The electrolyte-supported single cell with (PrBa)0.95Fe1.4Cu0.4Nb0.2O5+δ (PBFCu0.4N) anode achieves the highest peak power density of 431 mW cm-2 at 800 °C with activated carbon as the fuel. Moreover, a power generation unit is also made to demonstrate the practical utilization of PBFCN, which delivers a peak power of 0.51 W at 800 °C without any carrier gas, and a small fan can operate for more than 10 h by using the as-fabricated HDCFC as a power generation unit. The PBFCN anode achieves greatly enhanced catalytic activity by improving the chemical adsorption and electrochemical oxidation of CO at the anode/CO interface, which is mainly due to the high-activity Cu ions in PBFCN. The inactive element Nb doping and ordered layered structure endow the material with excellent redox structural stability. The present study provides a new idea for the design and development of high-performance anode materials for HDCFCs applications.

Cu-Doped Sr2Fe1.5Mo0.5O6-δ as a highly active cathode for solid oxide electrolytic cells.

Perovskite oxide Sr2Fe1.3Cu0.2Mo0.5O6-δ (SFCM) is prepared and evaluated as a novel cathode material for solid oxide electrolytic cells (SOECs). At 750 °C, the interfacial polarization resistance value decreased from 1.834 to 1.125 Ω cm2 and the SFCM cathode exhibited excellent stability for 100 h, without any significant attenuation, at an electrolytic voltage of 1.5 V.

[Comparative study on normal tongue manifestation in patients with primary liver cancer and healthy adults].

OBJECTIVE: To find out some microscopically visible morphological differences in normal tongue manifestation between patients with primary liver cancer and healthy adults, and provide some beneficial evidences for microcosmic syndrome differentiation of tongue inspection. METHODS: Microcirculations of the tongue tip, which represented the macroscopical normal tongue manifestation, were observed under an optical microscope in patients with primary liver cancer and healthy adults. Exfoliated cells from tongue coating were examined by hematoxylin-eosin staining. RESULTS: The proportion of normal tongue manifestation was larger in healthy adults (38.89%) than that in patients with primary liver cancer (2.32%). The total score of microcirculation of tongue tip and the maturation index of exfoliated cells from tongue coating were both higher in patients with primary liver cancer than those in healthy adults with normal tongue manifestation (P<0.01, P<0.05). CONCLUSION: Normal tongue manifestation, which is macroscopically visible, can be observed in both patients with primary liver cancer and healthy adults, but there exists obvious difference in microcosmic view.

[Characteristics of sublingual venae in primary liver cancer patients in different clinical stages].

OBJECTIVE: To explore the characteristics of the sublingual venae in patients with primary liver cancer (PLC). METHODS: The shape, color and the red, green and blue values of the sublingual venae were analyzed quantitatively for PLC patients in different clinical stages by analysis system for comprehensive information of tongue diagnosis. RESULTS: With the aggravating of the disease, the patients' sublingual venae became wide and tortuous, and their color became blue and purple. The abnormality of the sublingual venae was more serious in clinical stage III than in stages I and II (P < 0.05). CONCLUSION: The shape, color and abnormality degree of the sublingual venae in patients with PLC in different clinical stages are distinct.

[Quantitative study on tongue color in primary liver cancer patients by analysis system for comprehensive information of tongue diagnosis].

OBJECTIVE: To explore the characteristics of tongue color in patients with primary liver cancer (PLC). METHODS: Tongue color and its RGB value were analyzed quantitatively for PLC patients in different clinical periods and other cancer patients by analysis system for comprehensive information of tongue diagnosis. RESULTS: The rate of blue and purple tongue was higher (P<0.05) and all the values of RGB were lower (P<0.01) in PLC patients compared with other cancer patients. In different clinical periods, the rate of blue and purple tongue in stage III was the highest (P<0.05). CONCLUSION: The blue and purple tongue is one of the most important tongue characteristics of PLC patients.