Inorganic Chemistry Frontiers
·
2022
·Vol. 10
·期 3
·804-814
·
IF 7.779
Hu Yao,Yinan Zheng,Siliang Yue,Songjie Hu,Wenyu Yuan,Xiaohui Guo
The oxygen evolution reaction (OER) has slow chemical dynamics in the electrochemical decomposition of water. Herein, we demonstrate that B-site substitution engineering on ABF3 is an efficient strategy to boost the OER activity due to the modified electronic structure. A series of perovskite fluorides with the formula NaCo1−2xFexNixF3 were fabricated via a simple hydrothermal process, in which Co was partially substituted by both Fe and Ni. The optimized perovskite fluoride exhibited a low overpotential of 265 mV at a current density of 10 mA cm−2 and outstanding electrochemical stability after 100 h continuous electrocatalysis for the OER. These results are superior to the state-of-the-art perovskite-based OER catalysts. The X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) results showed that the dual-substitution of Fe and Ni atoms not only produced higher valence Co3+ ions but also generated the more active species Fe3+. In addition, the produced metal oxyhydroxides (MOOH, M = Co, Fe, Ni) on the catalyst surface during OER activation could contribute both excellent catalytic activity and ultralong stability.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Tongzhou Li,Tao Huang,Qilin Wei,Wenchao Lin,Xiaoyan Lu,Xiaodong Shen,Shichao Zhou,Weizheng Liang,Bingsuo Zou
The [InX 4 ] − tetrahedron is a structure with stronger rigidity than the [InX 6 ] 3− octahedron, which makes it a possible blue light emitting material. In this study, the method of mixed B-sites is used to control the polyhedral transition in the crystal structure. In 3+ ions partially replace Pb 2+ ions to form the mixed B sites of Pb-In. The electronegativity difference of both causes clear energy transfer between Pb and In. The movement of the electron cloud causes a change in the polyhedral structure, which promotes the formation of [PbBr 5 ] 3− pyramid and [InBr 4 ] − tetrahedra. In this way, we have achieved the efficient blue light emission of [InBr 4 ] − tetrahedron for the first time. Under 372 nm UV light excitation, (PPh 3 H) 4 [PbBr 5 ][InBr 4 ] can achieve efficient blue emission, the photoluminescence quantum yield is 74.03 %, and the emission center at 463 nm. The rigid environment and the [InBr 4 ] − tetrahedron are the sources of the minor Stokes shift, and the self-trapping exciton of the zero dimensions [InBr 4 ] − tetrahedron is the source of efficient blue light emission. Meanwhile, we found that there are two optical transition processes between [PbBr 5 ] 3− and [InBr 4 ] − . One is the transfer from the excited state of [PbBr 5 ] 3− to the excited state of [InBr 4 ] − , and triphenylphosphine acts as the energy transfer medium of the two. The other is the transfer from the ground state of [PbBr 5 ] 3− (donor) to the excited state of [InBr 4 ] − (acceptor).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Yang Yang,Yifan Zhai,Huaicheng Xiang,Jie Li,Ying Tang,Liang Fang
Herein two cubic garnet ceramics Ca 3 TiBGe 3 O 12 (B = Mg, Zn) were prepared with optimal sintering temperatures of 1300 ℃ and 1200 ℃, respectively. Both ceramics exhibited promising microwave dielectric properties as well as rather low coefficient of thermal expansion ( α L ) of ε r = 11.95, Q×f = 83,000 GHz, τ f = −34.1 ppm/℃ and α L = 3.9 ppm/℃ for Ca 3 TiMgGe 3 O 12 , and ε r = 11.80, Q×f = 79,000 GHz, τ f = −42.9 ppm/℃ and α L = 4.0 ppm/℃ for Ca 3 TiZnGe 3 O 12 . Bond valence calculation reveals that Ca 2+ at the A-site is slightly compressed, Ge 4+ at C-site is rattling, and compressed Mg 2+ /Zn 2+ coexists with rattling Ti 4+ in the B-site. The large positive deviations (17.22% for Ca 3 TiMgGe 3 O 12 and 10.90% for Ca 3 TiZnGe 3 O 12 ) between the porosity corrected ε r (Corr) (12.32 and 12.41) and calculated ε r (C-M) (10.51 and 11.19) by the C-M equation were observed, which might be attributed to the combination of rattling effects in B-site and C-site. The relatively stronger rattling effect in Ca 3 TiMgGe 3 O 12 leads to a higher ε r and a τ f closer to zero than those of Ca 3 TiZnGe 3 O 12 . Besides, the Q×f values of Ca 3 TiBGe 3 O 12 (B = Mg, Zn) ceramics are mainly affected by relative density, packing fraction, and Raman mode (A 1 g ).
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Xiaowei Jia,Ruyu Zhang,Xianchun Liu,Yunfeng Li,Yueran Li,Xiaodan Yu,Yan Xing
Perovskite-like metal oxides (PLMOs), featuring unique structural and optical properties , exhibit great potential in photocatalytic water splitting field. However, the wide bandgap and strong carrier recombination severely suppress their photocatalytic hydrogen production activity. Thus, design and development of novel PLMO photocatalyst with extended photo-response range and enhanced photo-generated charge separation/transport efficiency remains an ongoing challenge. Herein, a series of novel B-site substituted KCuTa 3-x Nb x O 9 solid solution photocatalysts were synthesized via a simple solid-state reaction method. With an increased content of Nb, a distinct red-shifted of the optical absorption edge of KCuTa 3-x Nb x O 9 solid solution was observed, leading to a decreased bandgap (from 2.69 to 1.91 eV), and a positive shift of the conduction band bottom (from −0.54 to −0.49 eV vs RHE). All of the Nb-substituted KCuTa 3 O 9 solid solutions exhibit enhanced separation efficiency of photoinduced charge carriers, which leads to increased hydrogen evolution activity, among which KCuTa 0.75 Nb 2.25 O 9 exhibits the highest hydrogen evolution rate of 2.16 μmol h −1 under the visible light irradiation (λ > 420 nm), which is approximately 7-fold higher than that of the pure KCuTa 3 O 9 . This study demonstrates the potential of modulating band structure through constructing solid solutions for efficient perovskite-like metal oxides photocatalysis .
研究领域:
材料科学
·
光催化
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Shibo Wu,Jingrui Cao,Yang Zhou,Jiahao He,Jiangjie Zhou,Muslum Demir,Hongye Yang,Zaizai Tong,Pianpian Ma
High-entropy perovskite oxides, an emerging electrocatalytic electrode material, integrates the distinctive features of high-entropy materials and perovskites, offering significant potential in electrocatalysis. While adjusting the B-site elements has been a widely adopted approach for modulating the electrocatalytic activity of HEPs, there was a notable lack of systematic investigations into the role of A-site ions in regulating their electrocatalytic performance. To overcome this deficiency, in the present study, La 1-x Na x (CrMnFeCoNi) 1/5 O 3 HEPs were synthesized using carbon nanotubes-based sacrificial template method. It was found that the Na substitution at the A-site not only significantly reduced the synthesis temperature but also facilitated the preservation of carbon nanotubes. This retention contributed to the formation of a three-dimensional network structure, exposing a greater number of active sites. The Na modification induced significant valence fluctuations at the B-site and tailored the oxygen vacancy concentrations, enhancing the synergistic "cocktail effect" among the various metal atoms. Furthermore, the introduction of Na stimulated the formation of surface M-OOH species, which serve as active intermediates to enhance OER activity. As a result, the Na-modified HEPs demonstrated exceptional OER performance compared to their parent phases. Among these, La 0.6 Na 0.4 (CrMnFeCoNi) 1/5 O 3 (L6N4-5M) sample exhibited a lower overpotential of 313 mV at a current density of 10 mA cm −2 and a Tafel slope of 47.4 mV dec −1 . Additionally, the A-site Na modification strategy and the in-depth investigation of the OER mechanism provide valuable insights for the future design and development of high-performance HEP electrocatalysts.
研究领域:
材料科学
·
电催化领域
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Zhengrong Liu,Zilin Zhou,Jiaming Yang,Yueyue Sun,Chaofan Yin,Ruhuan Li,Kai Wu,Athanasios Chatzitakis,Jun Zhou
The traditional oxygen electrode in solid oxide electrolysis cells (SOECs), (La,Sr)(Co,Fe)O3 (LSCF), suffers from high cost, evaporation at high temperatures, and societal aspects of the use of Co. In this work, a Co-free B-site multielement (so-called high-entropy) perovskite oxide, La0.6Sr0.4Cu0.2Fe0.2Ti0.2Mn0.2Ni0.2O3-δ (LSCuFTMN), has been synthesized and successfully applied as a novel oxygen electrode. X-ray photoelectron spectroscopy (XPS) data indicate that the multiple transition elements in the B-site exist in various valence states, leading to a spatially variable electron structure. Electrochemical measurements of LSCuFTMN suggest that the material exhibits extraordinary catalytic activity and stability under the studied working atmospheres and a decrease in polarization resistance by 24% compared to LSCF. By distribution of relaxation time (DRT) analysis, LSCuFTMN possesses better mass and charge transfer performance than traditional LSCF. An SOEC with LSCuFTMN as the oxygen electrode has been assembled and tested, and a current density of 1.2 A cm–2 is obtained at 2.0 V and 800 °C in electrolysis of pure CO2, higher by nearly 50% compared to LSCF. The faradaic efficiency is over 95%. No clear recession is observed in the long term stability test. It is evident that multication – so-called high-entropy – oxides could be promising materials for improving the working performance of SOECs.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2020
·Vol. 8
·期 23
·2001073
·
IF 8.286
Junnan Li,Xuechun Wang,Yeshu Tan,Dong Liang,Yatao Zou,Lei Cai,Tian Wu,Kaichuan Wen,Yusheng Wang,Yajuan Li,Tao Song,Lu Wang,Baoquan Sun
Halide perovskites are promising emitters for light-emitting diodes (LEDs) due to their outstanding optoelectronic properties, i.e., tunable bandgap, high photoluminescence quantum efficiency, and excellent color purity. However, in contrast to their green and red cousins, the present blue perovskite LEDs are still suffering from poor operational lifetime and electroluminescence shift during bias operation, hindering their practical applications in full-color information displays. Developing rational strategies to achieve efficient and stable blue perovskite LEDs is one of the urgent tasks in this community. Herein, through substituting the Pb site with strontium ions, blue perovskite films with stable emission under relatively harsh working conditions, i.e., high electrical bias, constant thermal heating, and UV illumination, are obtained, which accordingly guarantees spectrally stable blue perovskite LEDs with external quantum efficiency of 4.1%. Moreover, different alkaline-earth metal ions are also investigated to further explore the effects of B-site ion substitution on the performance of perovskite LEDs. This work demonstrates an alternative path for the development of spectral-stable blue perovskite LEDs.
研究领域:
材料科学
·
光电技术
·
半导体物理
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2023
·Vol. 57
·期 1
·015301
·
IF 3.4
Xiao Zhang,Zhe Xiong,Bin Tang,Chengtao Yang
The rapid advancement of mobile communications technology is imposing greater demands on electronic components. Microwave dielectric ceramics with a high dielectric constant (r) are crucial for the miniaturization and integration of microwave devices. Herein, The perovskite-structured (Ca0.61Nd0.26)1−x(Li0.5Nd0.5)xTiO3 (0 ⩽ x ⩽ 0.8) microwave dielectric ceramics with high r value were prepared by solid-state reaction method. The results demonstrated that the r value reached its peak at x = 0.6, which was influenced by the bond valence at B-sites. The τf and Q× f values decreased with increasing x value. Doping (Li0.5Nd0.5)2+ at A-sites led to an increase in the full width at half maximum of Raman peaks, indicating higher internal loss. A high dielectric constant and temperature-stable (Ca0.61Nd0.26)0.27(Li0.5Nd0.5)0.73TiO3 ceramic can be sintered with good microwave dielectric properties of r = 129.4, Q× f= 2,787 GHz, and τf = +1.9 ppm/°C.
研究领域:
材料科学
·
电气工程
·
微波技术
·
陶瓷
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）