Advanced Energy Materials
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2022
·Vol. 12
·期 22
·2200392
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IF 29.698
Peng Zhong,Kazuaki Toyoura,Lulu Jiang,Lubing Chen,Sara Adeeba Ismail,Naoyuki Hatada,Truls Norby,Donglin Han
A significant hydration and protonic conduction in La 2 NiO 4+ δ -based Ruddlesden–Popper (RP) oxides will enable their use as positrode materials in proton ceramic electrochemical cells (PCECs). Unlike perovskite electrolytes and positrode materials, where protons reside and jump on regular oxide ions, RP oxides such as La 2 NiO 4+ δ may contain oxygen interstitials and offer the possibility that protons locate on and migrate by help of these, suggesting a mechanism by which positrodes may operate by triple conduction. Here, theoretical calculations that support proton migration between interstitial oxide ions in the rock-salt layer via unshared oxide ions in the perovskite layer are reported. Furthermore, water contents of pristine La 2 NiO 4+ δ and La 2- x A x NiO 4+ δ ( A = Ca, Sr, Ba) are reported, showing that hydration increases with the level and basicity of the dopant. Hebb-Wagner blocking electrode measurements show significant partial protonic conductivity in all samples. The effects of doping on hydration and of p H 2 O on the p-type conductivity suggest that protons reside primarily on structural oxide ion, but a role of interstitial oxide ions for dissolution and migration of protons cannot be ruled out in cases with oxygen excess. The results are instructive for further studies and optimization of RP oxides as potential positrode materials for PCECs.
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
Liping Fang,Kai Wang,Chen Han,Xinyong Li,Pei Li,Jieshan Qiu,Shaomin Liu
Piezocatalysis utilizes mechanical energy to achieve the required charge separation for redox reactions, a promising method for clean H 2 O 2 production. However, the efficiency of conventional piezocatalysts is limited by the undesirable low piezoelectricity. Herein, novel piezocatalysts composed of La, Sr, Co (Fe) in simple single perovskites (La 0.5 Sr 0.5 FeO 3-δ and La 0.5 Sr 0.5 CoO 3-δ ) and Ruddlesden-Popper (R-P) type perovskites (LaSrFeO 4-δ and LaSrCoO 4-δ ) are developed for piezocatalytic H 2 O 2 production. Results indicate that Fe-containing catalysts outperform Co-containing counterparts and the unique R-P perovskite oxides demonstrate significantly enhanced piezocatalytic performance than the corresponding single perovskites. For example, via piezocatalysis, the LaSrFeO 4-δ exhibits H 2 O 2 yields of 548 (in 10 % ethanol) and 247 µmol g −1 h −1 (without sacrificial agent), improved by a factor of 1.14, 4.94, or 21.73 compared to La 0.5 Sr 0.5 FeO 3-δ , LaSrCoO 4-δ , or La 0.5 Sr 0.5 CoO 3-δ , respectively. The piezoelectricity is an overwhelming factor in determining the H 2 O 2 generation. Furthermore, the piezoelectricity and oxygen vacancy (OV) content is well correlated. The R-P phase with lower OV exhibits a higher piezoelectricity because of the eliminated pining effect to the polarization domain reversion. Mechanism exploration suggests that H 2 O 2 formation stems from the efficient O 2 reduction via a 2-electron transferring pathway, during which the piezoelectric polarization drives the charge separation and transportation, favoring the redox reactions.
研究领域:
材料科学
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环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2024
·
IF 13
Lubing Chen,Guanchao Wang,Kazuaki Toyoura,Donglin Han
Oxygen-excess La 2 NiO 4+ δ (LNO) conducts oxide ions, electron holes, and hydroxide ions simultaneously on exposing to wet oxygen, exhibiting the potential as a cathode material in protonic ceramic fuel cells. Since the incorporation of protons in oxygen-excess LNO is via the hydration reaction assisted by interstitial oxide ions, in this work, the concentration of interstitial oxide ions is reduced and increased by substituting Ni with Cu and Co, respectively. A higher concentration of interstitial oxide ions leads to a high proton concentration, indicating the predominant role of interstitial oxide ions in the hydration reaction, different from that in the oxygen-deficient oxides, where protons are introduced by dissociative absorption of water molecules by oxygen vacancies. The theoretical calculation indicates that protons in Co-doped LNO prefer to locate between the interstitial oxide ions and unshared apical oxide ions. A trapping effect is found between protons and the oxide ions near Cu, leading to decreased proton mobility. Protonic conductivity at 400–575 °C is then directly measured by a Hebb–Wagner direct current polarization method with La 0.99 Ca 0.01 NbO 4− δ as the blocking electrode, enabling the observation that Co-doped LNO has the highest protonic conductivity among the samples studied in this work.
研究领域:
材料科学
·
燃料电池研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhiyuan Pan,Sihan Feng,Fan Li,Xuejiao Wang,Qi Zhu,Ji-Guang Li
Near-infrared phosphor converted light-emitting diodes (NIR pc-LEDs), as a state-of-the-art type of NIR sources, are finding multifaceted applications, where phosphor is a crucial component. In hope to provide new choices for NIR lighting, we synthesized in this work the two series of Ruddlesden -Popper type layered perovskite phosphors of SrLa 2 Al 2- x O 7 : x Cr 3+ ( x = 0–0.02) and SrLa 2- y Gd y Al 1.984 O 7 :0.016Cr 3+ ( y = 0–2), followed by detailed structure and luminescence investigation. SrLa 2 Al 2- x O 7 : x Cr 3+ was found to emit ∼700–800 nm NIR light under UV excitation and be able to maintain ∼54.3 % of its room temperature intensity at 423 K, which is remarkably higher than those (∼25–30 %@423 K) of the Mn 4+ activated perovskite NIR phosphors. Luminescence regulation was achieved by substituting La 3+ with Gd 3+ , and it was revealed that Gd 3+ may act as a sensitizer to significantly enhance Cr 3+ luminescence (∼346 % at 77 K) through Gd 3+ → Cr 3+ energy transfer, which was confirmed by spectral and fluorescence lifetime analysis. The observed spectral features and the influence of Gd 3+ were rationalized by considering crystal structure, local coordination, and crystal field. Finally, an NIR pc-LED device showing strong ∼700–900 nm luminescence was fabricated to show potential application of the phosphor in night vision and plant lighting.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Wen-Jian Yang,Li-Hui Yang,Han-Jun Peng,Si-Hao Lv,Hafiz Muhammad Adeel Sharif,Wei Sun,Wei Li,Cao Yang,Hui Lin
Electroreduction removal of nitrate (NO 3 – -N) is considered as a promising approach to solve its adverse effects on environment and human health, where efficient and cheap catalysts are required. Perovskite-based catalysts showed a versatile catalytic ability for wide range of redox reactions, but seldom applied for NO 3 – -N reduction. Herein, four perovskite oxide cathodes, LaMO 3-δ (M = Fe, Co, Ni and Cu) were prepared and used for the reduction of NO 3 – -N. The Ruddlesden-Popper (RP) type La 2 CuO 4 exhibited the best NO 3 – -N catalytic activity among the four perovskite oxide cathodes, with a removal rate of 11.7 × 10 -3 min −1 . The high selectivity of NH 4 + -N (82.4 ± 2.2%) indicated that NH 4 + -N was the main final product for NO 3 – -N electroreduction at La 2 CuO 4 cathode, but 100% of N 2 selectivity could be obtained with addition of 1000 and 1500 mg/L Cl - as the electro-assisted chlorination process. The mechanism of NO 3 – -N electroreduction occurred by both electron- and H*-mediated pathway, and the oxygen vacancies and redox cycle of Cu(I)-Cu(II)-Cu(I) were proposed as the accommodation sties and direct electron sources for NO 3 – -N reduction. Generally, this study opens a novel avenue for the development of earth-abundant, cost-effective catalyst with effective NO 3 – -N electroreduction.
研究领域:
环境科学
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催化
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2021
·
IF 9.811
Feiyi Lyu,Xiaoqi Zheng,Ziyue Li,Zhuo Chen,Ruowen Shi,Zefeng Wang,Haiming Liu,Bo-Lin Lin
The motion of organic cations and its possible correlation with excited-state photodynamics are important to the fundamental understanding of the superior performances of two-dimensional (2D) and three-dimensional (3D) hybrid lead-halide perovskites in optoelectronic applications. Herein, variable-temperature (VT) solid-state 1H and 13C CP (cross polarization) NMR spectroscopy without isotope enrichments, combined with VT powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and time-resolved photoluminescence (TRPL), was employed to study the phase transition, local structure, motion dynamics, and photodynamic behaviors of organic cations in hybrid 2D Ruddlesden–Popper perovskites (RPPs) (BA)2(MA)n−1PbnI3n+1 (BA denotes butylammonium and MA denotes methylammonium). Two types of BA conformations in various crystalline phases of 2D RPPs and conformational transition associated with phase transition were clearly revealed. Quantitative NMR analyses suggest that the rotation dynamics of MA in 2D RPPs are comparable to that of MA in 3D MAPbI3. A surprising linear relationship was discovered between the estimated activation energy of the MA rotation and the logarithm of photoluminescence (PL) lifetimes (τ) of 2D RPPs and MAPbI3, strongly supporting the presence of coupling between the cation spatial dynamics and the excited-state photodynamic behaviors.
研究领域:
材料科学
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光电学
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固体物理
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2021
·
IF 9.229
Hualin Zheng,Ting Zhang,Yafei Wang,Canzhou Li,Zhenhuang Su,Ze Wang,Hao Chen,Shihao Yuan,Yiding Gu,Long Ji,Jian Li,Shibin Li
Despite two-dimensional (2D) Ruddlesden–Popper-phase layered perovskites (RPLPs) exhibiting excellent environmental stability, most solar cells based on 2D RPLP films are fabricated in a controlled inert atmosphere. Meanwhile, the poor charge transport of 2D RPLP films owing to the unfavorable phase arrangement and defects limits the efficiency of 2D RPLP solar cells. Here, we fabricate high-efficiency 2D RPLP solar cells in ambient air assisted by a zwitterion (ZW) additive. We show that the ZW additive suppresses the formation of the bottom 2D phases (n ≤ 2) and the top 3D-like phases in 2D RPLP films. These 2D phases usually grow parallel to the substrate and act as trap sites that inhibit charge transport in the vertical direction. The 3D-like phases, on the other hand, aggravate the long-term stability due to the intrinsic instability of MA+ cations. With improved phase distribution, crystal orientation, and reduced trap states in 2D RPLP films, efficient charge transport is obtained. Finally, a record-high open-circuit voltage (Voc) of 1.19 V and a power conversion efficiency of 17.04% with an enhanced stability are achieved for (BA0.9PEA0.1)2MA3Pb4I13-based (n = 4) solar cells fabricated under high humidity (∼65% RH).
研究领域:
材料科学
·
太阳能
·
纳米技术
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）