APPLIED ENERGY
·
2019
·
IF 8.426
Rong-hua Yuan,Yun He,Wei He,Meng Ni,Michael K.H. Leung
The development of efficient noble-metal free electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great importance for energy storage devices, such as fuel cell and zinc-air battery. In this work, we report a facile approach to enhance the electrocatalytic activity of La 0.8 Sr 0.2 MnO 3 -based perovskite by introducing the deficiency in the A-site and transition-metal Fe in the B-site. Bifunctional electrocatalysts La 0.8 Sr 0.2 MnO 3 , (La 0.8 Sr 0.2 ) 0.98 MnO 3 , (La 0.8 Sr 0.2 ) 0.95 MnO 3 and (La 0.8 Sr 0.2 ) 0.95 Mn 0.5 Fe 0.5 O 3 were prepared by a facile sol–gel process. The material characterization results showed that compared with La 0.8 Sr 0.2 MnO 3 , (La 0.8 Sr 0.2 ) 0.98 MnO 3 and (La 0.8 Sr 0.2 ) 0.95 MnO 3 have smaller particle size, more oxygen vacancies and proper Mn valence, which will benefit both ORR and OER. The results were verified by testing the electrocatalytic activities using rotating-disk electrode (RDE) in alkaline media. For the perovskite oxides with only A-site cation deficiency, the bifunctional electrocatalytic activities increase in the following order: La 0.8 Sr 0.2 MnO 3 < (La 0.8 Sr 0.2 ) 0.98 MnO 3 < (La 0.8 Sr 0.2 ) 0.95 MnO 3 . With partial substitution of Mn by Fe in the B-site, the (La 0.8 Sr 0.2 ) 0.95 Mn 0.5 Fe 0.5 O 3 perovskite oxide exhibits even better electrocatalytic activity. Further experiments reveal that (La 0.8 Sr 0.2 ) 0.95 Mn 0.5 Fe 0.5 O 3 has the highest current density (4.5 mA cm −2 ) in ORR which is comparable to commercial Pt/C (5 mA cm −2 ) and the enhancement of the OER is more obvious than that of the ORR. Subsequently, the perovskite samples were used as the cathode catalysts in zinc-air batteries. The results further prove that proper use of A-site deficiency and B-site Fe doping in perovskite oxides can boost up the electrocatalytic activities.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2023
·
IF 8.7
Qunwei Guo,Jiaqi Geng,Jiawen Pan,Bo Chi,Chunyan Xiong,Jian Pu
Liquid fuels like diesel, biodiesel , and alcohols can be utilized for onboard hydrogen production in auxiliary power systems by steam reforming , in which hydrogen productivity and carbon deposition are key issues. A-site deficient La 1-x Cr 0.95 Ru 0.05 O 3 catalysts are prepared using the Glycine-nitrate method and characterized by multiple techniques. The catalyst with 20 % A-site deficiency exhibits about 95 % fuel conversion and stable performance over a 100 h continuous test at 750 °C and a steam/carbon ratio of 3.0 using n-hexadecane. However, the catalyst with a 10 % deficiency shows fluctuating fuel conversion with higher ethylene and ethane contents. Catalyst performance is mainly determined by active oxygen. The activation of steam on oxygen vacancies and Cr ions with variable valences could produce surface-free oxygen and freely migrating lattice oxygen respectively, which can react with CH x intermediates to form CO and H 2 .
研究领域:
能源材料化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 45
·17180-17191
·
IF 4.569
Liang Li,Qianwen Cao,Jing Xie,Wenming Wang,Yubei Wang,Hongmei Chen,Zhongyuan Li,Yan Pan,Xiantao Wei,Yong Li
Altering the local symmetry of an activator by lattice tuning is considered an effective strategy to optimize the luminescence performance of phosphors. Herein, the novel Mn4+-activated double perovskite phosphor La1.67MgTaO6 (LMTO) with A-site defects was successfully prepared. Benefiting from the random occupation of the nearest A-site by cations and vacancies, the distorted [MnO6] octahedra lack the inversion center. The LMTO:0.4 mol%Mn4+ phosphor has a significant zero-phonon line intensity with a high internal quantum efficiency (IQE) value of 62.97% after the Laporte selection rule is broken. Furthermore, local lattice tuning was performed by increasing the randomness of the A-site and the distortion index of the [MnO6] octahedron by co-doping with Ca2+ or Sr2+ ions. Importantly, the IQE value of the samples was enhanced from 62.97% to 72.65% and the activation energy increased from 0.497 eV to 0.548 eV, which can be well applied in the fields of plant cultivation and warm white light-emitting diodes. These studies provide valid fundamental insights for the selection of excellent luminescent matrices to obtain efficient Mn4+-activated phosphors via local lattice tuning.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2023
·
IF 6.4
Ziyi Zhu,Mingyang Zhou,Zidai Fan,Qiwen Wu,Kai Tan,Yan Liu,Yu Chen,Jiang Liu
Proton-conducting solid oxide cells are regarded as promising solid-state energy conversion devices to realize the high-efficiency conversion between electrical energy and chemical energy. However, the high cost, easily reducible ion characteristics, and large thermal expansion coefficient related to the valence state of the traditional high-catalytic cobalt-based oxygen electrode are unavoidable problems. Cobalt-free barium ferrite-based oxides with triple-conducting properties are considered the most promising prospective candidates for highly active oxygen electrode materials because of the increased electrochemical reaction active sites, excellent thermal stability, and low thermal expansion coefficient. In this work, by introducing 5% A-site deficiency at the atomic scale, the oxygen vacancy concentration is increased so that the catalytic reaction kinetics and proton-conduction ability of ABO3-type perovskite oxygen electrode material BaFe0.5Sn0.2Bi0.3O3−δ are improved. The effects of non-stoichiometry on the phase composition, microstructure, hydration capacity, thermal expansion characteristics, conductivity, and chemical stability are investigated. In both fuel cell and electrolysis cell operation modes, the proton-conducting solid oxide cells with the A-site-deficient Ba0.95Fe0.5Sn0.2Bi0.3O3−δ oxygen electrode demonstrate excellent electrochemical performance, giving a peak power density of 0.69 W cm–2 (increased by 19.0%) and an electrolysis current density of 1.64 A cm–2 (increased by 30.2%) at 700 °C. Moreover, even at 600 °C with 50% high steam partial pressure, electrolysis for hydrogen production is maintained for about 100 h without significant attenuation, confirming the vital role of A-site defect engineering in the design of advanced oxygen electrode materials.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Anqi Jiao,Yiran Zhang,Lin Yang,Xuteng Zhao,Chunping Wu,Ting Chen,Reggie Zhan,Zhen Huang,He Lin
Measuring the CO 2 concentration is the base of carbon accounting which aims to abate the greenhouse gas emission. This paper pays attention to developing sensitive material for CO 2 detection in vehicle exhaust. For this purpose, La 1-x FeO 3-δ nanoparticles with A-site deficiency were synthesized by flame spray pyrolysis (FSP). The dynamic response of the prototype CO 2 sensors was evaluated by checking the gas-mixture with 5%–15% CO 2 . It was observed that the amount of A-site deficiency would obviously affect the performance of the material. La 0.95 FeO 3-δ sensor exhibits the highest response (S = 3.38) and a relatively short response time (t 90 = 114s) among the serial La 1-x FeO 3-δ sensors (x = 0, 0.02, 0.05, 0.07 and 0.1). The improvement of the response might be attributed to the increase of oxygen vacancies and the higher valence of B-site cations caused by the introduction of A-site deficiency. Furthermore, the sensor exhibited good selectivity against NH 3 , NO, NO 2 and CO, as well as good repeatability. However, water vapor is still a disturbance in the response. The response at 40% RH and 80% RH are 2.11 and 1.73, respectively. Finally, the sensing mechanism based on the participation of the oxygen vacancies was discussed.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Small
·
2023
·Vol. 19
·期 41
·2303305
·
IF 13.3
Wanbin Lin,Weibin Su,Yanpu Li,Te-Wei Chiu,Manish Singh,Zehua Pan,Liangdong Fan
Solid oxide electrolysis cells (SOECs) hold enormous potential for efficient conversion of CO 2 to CO at low cost and high reaction kinetics. The identification of active cathodes is highly desirable to promote the SOEC's performance. This study explores a lithium-doped perovskite La 0.6- x Li x Sr 0.4 Co 0.7 Mn 0.3 O 3- δ ( x = 0, 0.025 0.05, and 0.10) material with in situ generated A-site deficiency and surface carbonate as SOEC cathodes for CO 2 reduction. The experimental results indicate that the SOEC with the La 0.55 Li 0.05 Sr 0.4 Co 0.7 Mn 0.3 O 3- δ cathode exhibits a current density of 0.991 A cm −2 at 1.5 V/800 °C, which is an improvement of ≈30% over the pristine sample. Furthermore, SOECs based on the proposed cathode demonstrate excellent stability over 300 h for pure CO 2 electrolysis. The addition of lithium with high basicity, low valance, and small radius, coupled with A-site deficiency, promotes the formation of oxygen vacancy and modifies the electronic structure of active sites, thus enhancing CO 2 adsorption, dissociation process, and CO desorption steps as corroborated by the experimental analysis and the density functional theory calculation. It is further confirmed that Li-ion migration to the cathode surface forms carbonate and consequently provides the perovskite cathode with an impressive anti-carbon deposition capability, as well as electrolysis activity.
研究领域:
材料科学
·
电化学
·
能源材料
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Small
·
2025
·
IF 12.1
Shupan Zhang,Lianfeng Ma,Yufan Wu,Mingyuan Xie,Wei Liu,Haoran Jiang,Bingyao Du,Yingqiao Jiang,Ling Wang,Lei Dai,Jing Zhu,Zhangxing He
Due to the inadequate electrochemical properties of the original graphite felt (GF), catalysts are needed to improve the performance of vanadium redox flow batteries (VRFBs). Introducing structural defects including oxygen vacancy defects and A-site defects in perovskite AZrO 3 (A = Ca, Sr, Ba) are used to promote the kinetics of vanadium ion redox reactions. The A-site ions are selectively etched and release lattice oxygen to form oxygen vacancies by acid treatment. Structural defects add additional active sites to enhance the adsorption capacity for vanadium ions and promote redox reactions. The electrochemical properties are influenced by a combination of the number of defects and the type of defects. In summary, SrZrO 3 shows the best electrochemical performance. SrZrO 3 -GF cell achieves 64% energy efficiency ( EE ) at 200 mA cm −2 , representing a 14.3% improvement over the pristine. The material also demonstrates excellent stability over 500 cycles in long-term testing. The strategy of introducing structural defects on the perovskite surface provides valuable insights and new strategies for catalysts in VRFBs, paving the way for more efficient battery systems.
研究领域:
电化学
·
材料科学
·
储能技术
·
表面工程
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Kai Ma,Yao Luo,Jietao Wang,Xu Chang,Tong Liu,Yao Wang,Mingyue Ding
Developing robust fuel electrodes with high catalytic activity and stability under CO/CO 2 atmospheres is critical for reversible solid oxide fuel cells (RSOFCs). Here, we report a novel A-site-deficient perovskite Sr 1.95 Fe 1.5 Mo 0.3 Ni 0.2 F 0.1 O 6-δ (SFMNF) synthesized via electrospinning, combining Ni 2+ (B-site cation) and F - (anion) co-doping to enhance CO 2 electrolysis and syngas oxidation performance. Physicochemical characterization reveals that F-doping lowers the crystallization temperature, increases oxygen vacancy concentration, and strengthens CO 2 chemisorption. Reduction under H 2 induces exsolution of Ni 3 Fe alloy nanoparticles. The SFMNF electrode achieves a current density of 233 mA cm -2 at 1.3 V and 750°C in CO:CO 2 =2:1 atmosphere, with 36.2% higher activity than the pre-reduced state. Electrochemical impedance and distribution of relaxation time analyses identify CO 2 adsorption/dissociation as the rate-limiting step. The cell demonstrates exceptional durability over 50 redox cycles and 85-hour of operation without carbon deposition. This work highlights dual doping as an effective strategy to tailor perovskite properties for efficient CO 2 utilization in RSOFCs.
研究领域:
能源材料
·
电化学
·
催化
·
纳米技术
·
固体氧化物燃料电池
·
CO2利用
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Pengyu Wei,Yaxin Lv,Changyang Liu,Ziliang Liu,Lilin Yang,Ruixue Tian,Jun Peng,Liuzhen Bian,Shengli An
Perovskite oxide-based materials are promising electrode materials for reversible symmetric solid oxide cells (RSSOCs) as they exhibit good catalytic activity and stability in oxidizing and reducing atmospheres. In this study, A-site deficient (La 0.5 Sr 0.5 ) 0.95 Fe 0.9 Mo 0.1 O 3-δ (95LSFMo) is synthesized as an electrode material for RSSOCs. The A-site defect in La 0.5 Sr 0.5 Fe 0.9 Mo 0.1 O 3-δ increases the surface oxygen vacancy concentration, promoting the transport of oxygen ions and enhancing the catalytic activities of oxygen reduction (ORR) and hydrogen oxidization reaction (HOR). 95LSFMo|LSGM|95LSFMo symmetric cell achieves a maximum power density (MPD) of 1.14 W cm −2 at 850 °C. Furthermore, the adsorption and reduction of H 2 O is also improved. In 50 %H 2 O-H 2 , 95LSFMo cell shows a current density of −1.71 A cm −2 at 850 °C and 1.3 V in electrolysis mode and a peak power density of 0.82 W cm −2 in fuel cell mode. The corresponding hydrogen production rate reaches 714.78 ml cm -2 h −1 . Moreover, the 95LSFMo cell exhibits good reversibility as well as SOEC stability.
研究领域:
材料科学
·
电化学
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）