CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Qiuyu Cheng,Xin Chen,Lin Liu,Peng Jiang,Deshi Song,M.A. Subramanian
Novel green and blue chromophores based on Ni/Co/Cr doped BaMg 6 Ti 6 O 19 solid solutions are successfully synthesized through a solid-state reaction. The crystal structure of all the samples belongs to the magnetoplumbite structure with the space group of P 6 3 / mmc . The BaMg 6- x /2 Ti 6- x /2 Ni x O 19 (0 ≤ x ≤ 0.3) compounds exhibit a light green ( x = 0.1) to yellow-green ( x = 0.3) color. The oxidation state of Ni is confirmed to be +2 valence and the d-d transition of Ni 2+ in octahedral sites is responsible for color. BaMg 6- x /2 Ti 6- x /2 Co x O 19 (0 ≤ x ≤ 0.3) series show a blue color and the intensity of blueness is increasing with the increase of Co content. The blue color is due to d-d transitions within Co 2+ present in the tetrahedral sites. For BaMg 6- x /2 Ti 6- x /2 Cr x O 19 (0 ≤ x ≤ 2) phases the color varies from light green ( x = 0.2) to green ( x = 2). Chromium exists in +3 and + 6 oxidation states and the observed color is due to charge transfer transition between Cr 3+ –Ti 4+ and d-d transitions within octahedral Cr 3+ sites resulting in strong absorption in the visible region. The synthesized colored oxides are mixed with PMMA to prepare novel green and blue PMMA polymer composites to evaluate their compatibility in plastics.
研究领域:
材料科学
·
固体化学
·
光学材料
·
聚合物科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2024
·
IF 3.1
Yu Yan,Dongxiao Li,Zhimin Guo,Hao Ren,Yubiao Huang,Bei Yan,Ruihuan Zhao,Xin Yao
Developing efficient, low-price non-noble metal-based electrocatalysts for overall water splitting in alkaline medium remains a formidable challenge. In our work, Cr-doped CoP/Fe2P (Cr-CoP/Fe2P) flower-like microsphere was synthesized through a simple hydrothermal and phosphating process. The resulting Cr-CoP/Fe2P electrocatalyst shows significantly enhanced oxygen evolution reaction performance (262 mV @ 10 mA cm-2) and has a satisfactory hydrogen evolution reaction performance (114 mV @ 10 mA cm-2), coupled with favorable stability in an alkaline medium. Furthermore, when assembling Cr-CoP/Fe2P into an electrolytic cell, the two-electrode system can provide a current density of 10 mA cm-2 at a voltage of 1.61 V. At high current density, the performance of the electrolytic cell composed of Cr-CoP/Fe2P is superior to that of noble metal catalyst electrode pair. Electronic structure analysis and various characterizations confirm that Cr doping and the formation of CoP/Fe2P heterogeneous interfaces redistribute the electron densities of the active sites, enlarge the specific surface area, and enhance the aerophobicity of the catalysts, thereby improving the electrocatalytic property. This work provides a referable method for engineering highly efficient and stable non-noble polymetallic phosphides, which serve as bifunctional electrocatalyst for overall water splitting.
研究领域:
材料科学
·
电化学
·
催化
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Jiangping Jing,Zhuoyuan Chen,Yuyu Bu,Mengmeng Sun,Wenqiang Zheng,Weibing Li
SrTiO 3 is a promising material for the photoelectrochemical (PEC) cathodic protection technology due to its intrinsic band structure . Its disadvantage of light absorption only in the ultraviolet region can be effectively solved by Cr doping. The Cr dopant usually exists as two states of Cr 3+ and Cr 6+ , among which the latter one usually behaves as the trapping center for the photoinduced electrons and leads to the decrease of the PEC performance. In this paper, a hydrogen treatment process is performed on the Cr-doped SrTiO 3 to reduce the Cr 6+ . It is verified that hydrogen treatment reduces Cr 6+ to Cr 3+ , leading to the increase of the concentration of the charge carriers and the decrease of the charge transfer resistance. And also, hydrogen treatment induces the formation of oxygen vacancy , which leads to the negative shift of conduction band potential and the increase of the concentration of the charge carriers. The effect of the hydrogen treatment temperature is further studied in this work. Higher temperature will promote the reduction degree of Cr 6+ and increase the concentration of oxygen vacancy . However, hydrogen treatment with excessively high temperature will induce too high concentration of oxygen vacancy, which would act as the recombination centers of the photogenerated charge carriers, suppress the mobility conduction and thus lead to the decrease of the PEC performance. Therefore, benefiting from the Cr 6+ reduction and modification with appropriate concentration of oxygen vacancy, the Cr-doped SrTiO 3 with hydrogen treatment at 250 °C shows the optimal PEC cathodic protection performance in NaCl solution.
研究领域:
材料科学
·
电化学
·
光电化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Yu Liu,Yingying Xing,Xinyu Zheng,Shengjie Xu,Di Li,Deli Jiang
Designing high-performance and earth-abundant bifunctional catalysts for electrocatalytic water splitting remains a great challenge. Herein, a novel electrode composed of Cr-doped Co 2 P with P vacancies nanowire arrays (denoted as CrCo 2 P(V p ) NWs) grown on nickel foam was fabricated via a hydrothermal and successive calcination method. The Cr doping and vacancy engineering synergistically enable the exposure of more active sites, optimize electronic structure, and accelerate the charge transport capability, thus enhancing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances. As a result, the obtained Cr 0.4 Co 2 P(V p ) NWs catalyst exhibits superior catalytic activities in 1.0 M KOH solution with low overpotentials of 37 mV at −10 mA cm −2 for HER and 253 mV at 20 mA cm −2 for OER, respectively. Furthermore, using Cr 0.4 Co 2 P(V p ) NWs as a dual-function catalyst only requires 1.54 V voltage at 10 mA cm −2 for overall water splitting. Notably, the Cr 0.4 Co 2 P(V p ) NWs catalyst displays satisfactory stability with only a small attenuation of 3.2% after 50 h in a constant current testing. This study highlights the synergistic effect between doping and anion-vacancies in the enhancement of electrocatalytic activities and provides a feasible strategy to design effective, earth-abundant, and stable bifunctional electrocatalysts for water splitting.
研究领域:
材料科学
·
电化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Guiying Tian,Jian Gao,Minrui Wang,Xintao Wen,Yutong Liu,Jun Xiang,Lei Zhang,Penggao Cheng,Jianping Zhang,Na Tang
Current explosive demand in raw lithium greatly boosts lithium mining, and electrochemical Li-extraction using spinel LiMn 2 O 4 (LMO) from original brine has gained much attentions. In this study, Cr-doped LMO is prepared via a facile precipitation-calcination to elucidate the structural alterations and suppress Jahn-Teller distortion, and a novel hybrid capacitive deionization (HCDI) system of “Li-poor LiMn 1.8 Cr 0.2 O 4 ||brine (recovery liquid)||activated carbon” is constructed for electrochemical Li-extraction. The results prove that Cr-doping effectively suppresses Mn 3+ disproportionation induced by Jahn–Teller distortion, leading to a stabilized spinel framework for long lifespan. Importantly, the Cr-doping LMO realizes a stable (de)lithiation over 500 cycles with low manganese dissolution rate of 0.027% per cycle. Meanwhile, the Li-extraction capacity can reach 22 mg g −1 in 1.0 M LiCl electrolyte with retention rate of 86.05% after 500 cycles. In the assembled HCDI system, average Li-extraction capacity in brine reaches ∼15 mg g −1 after 15 cycles. Therefore, the HCDI system using Cr-doping LMO could introduce a new perspective for the industrial Li-extraction facing original brine.
研究领域:
材料科学
·
电化学
·
能源存储
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Fanjia Sun,Yanhui Wang,Hongwei Gao,Xueqing Tian,Rui Zhu,Youbin Zheng,Jianbing Zang,Liang Dong
To address the challenges of the chlorine evolution reaction (CER) and catalyst corrosion in seawater electrolysis, this study developed a chromium-doped nickel-iron layered double hydroxide catalyst. This catalyst operates continuously for 100 h in alkaline seawater, showing consistent increases in activity. Chromium (Cr) doping strengthens the metal-oxygen (M-O) bond, inhibits the loss of lattice oxygen, and facilitates a shift toward the adsorbate evolution mechanism in the reaction pathway. Additionally, CrO 4 2- , produced by the in-situ oxidation and dissolution of Cr 3+ , establishes a dynamic “oxidation-dissolution-adsorption” equilibrium at the interface. This significantly reduces chloride ion (Cl - ) adsorption, corrosion, and the energy barriers of reactions. The introduction of a methanol-assisted system further decreases the overpotential. An electrolyzer that incorporates this system with Pt/C achieves efficient hydrogen production at a current density of 100 mA cm −2 and a voltage of 1.45 V.
研究领域:
电催化
·
材料化学
·
能源科学
·
界面化学
·
腐蚀防护
·
可持续能源技术
·
纳米材料
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 150
·期 9
·2497-2509
·
IF 2.482
Yang Qiang,Liu Jiali,Yan Dejian,Liu Jikai,Luo He’an
Abstract Boron-rich alloy boron suboxide (B 6 O) as a novel metal-free photocatalyst was recently explored for photocatalytic CO 2 reduction and water splitting. However, to broaden the potential applications of B 6 O in the field, further improving its activity and understanding its fundamental chemical properties are essential. Herein, transition metal doping (Cr or Co) is designed to engineer the band structure of B 6 O via a solid state reaction. The valence band edge of Cr or Co doped B 6 O is proposed to be more positive than that of pristine B 6 O while the original conduction band of B 6 O is not much influenced by doping, contributing to the better light harvesting ability and lower charge recombination rate of doped B 6 O. The photocatalytic and photoelectrochemical (PEC) performances of doped B 6 O were therefore remarkably enhanced. The apparent quantum yields (AQY) of 20 wt% Cr or Co doped B 6 O are much higher than that of pristine B 6 O. In addition, the 20 wt% Cr doped B 6 O exhibits the best electrical conductivity and photocatalytic performance compared with the Co doped B 6 O and pristine B 6 O. The present work demonstrates a facile and effective strategy to engineer the band structure and reduce the charge migration resistance of B 6 O. Graphic Abstract
研究领域:
材料科学
·
光催化
·
可再生能源
✓ 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）