FUEL
·
2024
·
IF 6.7
Yang Liu,Shaokai Ma,Shiqing Zhang,Fang Liu,Ying Wang,Xinyu Sun,Ying Li,Yanming Xue,Chengchun Tang,Jun Zhang
Efficient and sustainable hydrogen production via water electrolysis relies on the utilization of highly active electrocatalysts for the oxygen evolution reaction (OER). Birnessite (δ-MnO 2 ), a type of manganese oxide with a local atomic structure similar to the oxygen-evolving complex in photosystem II, has emerged as a highly promising OER catalyst. Despite considerable efforts have been dedicated to enhancing its activity, the crucial aspect of stability has been often overlooked. Herein, Ti ions have been selectively incorporated into the in-layered lattice of δ-MnO 2 nanosheet arrays using a hydrothermal method, aiming to enhance the stability without reducing its activity. The resulting optimal Ti-MnO 2 catalyst demonstrates enhanced OER activity in alkaline electrolyte, exhibiting an impressive 85 mV reduction in overpotential at 10 mA cm −2 , surpassing the initial MnO 2 (495 mV reduced to 410 mV). Remarkably, it shows exceptional durability, with negligible performance decrease observed over the entire 50-hour testing period. It has been demonstrated that the incorporation of Ti serves a dual purpose: it adjusts the electronic structure around Mn, enhancing activity, and simultaneously stabilizes the Mn 3+ active sites, resulting in exceptional durability. Furthermore, density functional theory (DFT) calculations provide additional confirmation of the optimized electronic structure of MnO 2 achieved through Ti doping, leading to a reduction in the free energy of adsorbed intermediates and expediting the kinetics of the OER process. Our findings open a pathway for enhancing OER stability and activity by doping electrocatalytic inert ions into the lattice of MnO 2 , applicable not only to Mn-based oxides but also other non-precious metal-based electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2019
·Vol. 19
·期 6
·3437-3446
·
IF 1.093
Niu Yakun,Zhou Yi,Niu Ping,Shen Haiyan,Ma Ying
Ti doped hematite photoanodes have been intensively investigated due to their excellent activity for photoelectrochemical water oxidation. However, little attention has been paid to the doping effect on the photocurrent onset potential of hematite and the underlying mechanism. In this
paper, Ti doped hematite nanorod arrays were successfully prepared through a facile treatment of hematite with TiCl3 solution. The photocurrent of the Ti doped hematite photoanode increases by three times, and its onset potential shifts more positively as compared with that of the
undoped one. Electrochemical analyses were employed to unravel the mechanism of anodic shift of the onset potential. Cyclic voltammograms and electrochemical impedance spectra confirmed that more surface states were formed in Ti doped hematite than the undoped one. As a result, lower activity
towards oxygen evolution reaction (OER) and increased electron–hole recombination after light on/off in low potential region were observed in Ti doped hematite. It is concluded that these doping induced surface states may be a hindrance to charge transfer and the onset potential of Ti
doped hematite shifts anodically.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Yanhong Gu,Jianguo Zhao,Weiying Zhang,Haiwu Zheng,Laimei Liu,Wanping Chen
Sm and Ti co-doped BiFeO 3 (BFO) ceramics with Fe vacancies—Bi 0.86 Sm 0.14 FeO 3 , Bi 0.86 Sm 0.14 Fe 0.99 Ti 0.01 O 3 , and Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 —were prepared by a solid-state method using a rapid liquid process. X-ray diffraction indicated that all samples exhibited a rhombohedral structure with a minor secondary phase. The structural transformation from a rhombohedral (space group: R 3 c ) to orthorhombic structure (space group: Pnma ) was observed in the sample of Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 , which was also confirmed by Raman scattering spectra. Microstructural investigations with scanning electron microscopy showed a reduction in grain size with doping of BFO. The dielectric loss of Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 reaches 0.05 (at 100 Hz) owing to the introduction of Ti and Fe vacancies. Ferroelectromagnetic measurements revealed the existence of ferroelectricity with a remanent polarization of 0.24 µC/cm 2 in Bi 0.86 Sm 0.14 FeO 3 , paraelectricity in Bi 0.86 Sm 0.14 Fe 0.9 Ti 0.05 O 3 , and weak ferromagnetism with a remanent magnetization of 0.2 emu/g in Bi 0.86 Sm 0.14 Fe 0.99 Ti 0.01 O 3 . The two composition-driven phases exist simultaneously and the different coercive field might be related to the jumps in the ferromagnetic hysteresis loops. Both the ferroelectric and magnetic properties were shown to correlate with the composition-driven structural evolution.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2017
·
IF 4.536
Chaonan Mu,Kaixiang Lei,Haixia Li,Fujun Li,Jun Chen
Tunnel-type Li3VO4 (LVO) has become of great interest as a promising anode material for lithium-ion batteries owing to its large capacity, low cost, and safe potentials. However, the poor conductivity of LVO limits its wide applications. Here, LVO was doped with 0.05 unit of Ti4+ in each formula (LTVO) via a solid-state synthetic method to increase its conductivity and structural stability. The partial replacement of V5+ with Ti4+ leads to formation of additional interstitial Li+ ions in the octahedrons between MO4 (M = Li, V) tetrahedrons and hence improves Li+ ion diffusion kinetics. The resultant LTVO electrode exhibits a high discharge/charge capacity of ∼376 mAh g–1 at 20 mA g–1. Good cycling stability over 500 cycles with small polarization is achieved at 1000 mA g–1. This makes it a promising anode for Li-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 13
·期 22
·6561-6569
·
IF 5
Songlei Mo,Yong Guo,Xiaohui Liu,Yanqin Wang
The glycolysis of polyethylene terephthalate (PET) is considered as the most promising PET recycling strategy due to its mild reaction conditions and circularity. Herein, several metal-doped SBA-15 (M/SBA-15) as heterogeneous Lewis acid catalysts were investigated to screen the best catalyst and to understand the essence for their differences in PET glycolysis. It is found that the catalytic activity is positively correlated with the acid amount in different metal-doped SBA-15 and Ti/SBA-15 with different Ti loadings, with the exception of Nb/SBA-15. 4Ti/SBA-15 with abundant Lewis acid sites shows excellent PET glycolysis ability, with the yield of bis(2-hydroxyethyl) terephthalate (BHET) reaching 87.2% within 45 min at 190 °C (isolated yield 73%). While 4Nb/SBA-15 has a similar acid amount as that in 4Ti/SBA-15, but it has very low catalytic activity probably due to its strong oxygen affinity. Acetone–methanol-adsorption DRIFTS confirms its strong oxygen affinity, which would poison the acid sites by ethylene glycol (EG) and result in very low activity. This study demonstrates that PET glycolysis activity is really correlated with the amount of Lewis acid sites, but species with very strong oxygen affinity would lower its activity. Further diffuse reflection ultraviolet-visible (DR UV-vis) spectra analysis confirms that tetrahedral Ti4+ species in Ti/SBA-15 is the real active center. In addition, 4Ti/SBA-15 has good reusability and can be used in common real PET (dyed polyester fabric, PET bottles) glycolysis. These results indicate that increasing the amount of Lewis acid sites is a promising way to enhance PET glycolysis and 4Ti/SBA-15 with high activity and stability is a potential catalyst for industrial application.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2016
·Vol. 51
·期 12
·5712-5723
·
IF 2.302
Rong Nannan,Chu Mengsha,Tang Yulin,Zhang Chao,Cui Xun,He Huichao,Zhang Yunhuai,Xiao Peng
Because of the potential application in photoelectrochemical cells for water splitting, the synthesis of BiFeO 3 (BFO) is receiving increasing attention. A simple, low-cost drop-casting route was used to synthesize Ti ions doped BiFeO 3 thin films and the effects of the Ti ions doping on their crystal structure, morphology, and photoelectrocatalytic activity had been studied. X-ray diffraction results of Ti-BFO films showed that the doping of Ti ions lead to the distortion of crystal structure. Photoelectrochemical measurements indicated that the photoelectrocatalytic activities of BFO film doped with 5 % Ti ions showed the best performance. The UV–Vis absorption spectra of Ti-BFO films showed that the absorption wavelength of BFO doped with 5 % Ti had obvious shift and the band gap decreased. From the results of Mott–Schottky (M–S) plots, we calculated the positions of valence band (VB) and conduction band (CB) for Ti-BFO film. The outcomes showed that the band gap structure of BFO samples doped with 5 % Ti had more positive CB and more negative VB. The calculated photogenic charge carrier concentrations of BFO and Ti (0.05)-BFO were 5.07 × 10 19 and 6.32 × 10 19 cm −3 , respectively. The reduced band gap and increased photogenic charge carrier concentration are the major factors contributing to the enhancement of photoelectrocatalytic performances of Ti-BFO films.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2020
·
IF 3.407
Longqing Chen,Wenbin Qiu,Hao Deng,Xiaoliang Yang,Yangyipeng Song,Jun Zhu,Jun Tang
The shrinkages presented in sintering process of tungsten alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑potassium (WK) alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten alloys with less shrinkages and ultra-fine grains.
研究领域:
材料科学
·
核能工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Materials Interfaces
·
2024
·Vol. 11
·期 22
·2400190
·
IF 4.3
Junhua Zhou,Huimin Hu,Jiaqi Wang,Qitao Shi,Xueyu Lian,Lijun Liu,Alicja Bachmatiuk,Jingyu Sun,Ruizhi Yang,Jin-Ho Choi,Mark H. Rümmeli
Sodium layered oxide with anion redox activity (SLO-A) stands out as a promising cathode material for sodium-ion batteries due to its impressive capacity and high voltage resulting from Mn- and O-redox processes. However, the SLO-A faces significant challenges in cycling stability and rate performance, primarily due to the poor reversibility and sluggish kinetics of the O-redox. In this study,a novel Ti-doped material, Na 2/3 Li 2/9 Mn 53/72 Ti 1/24 O 2 (NLMTO), exhibiting remarkable characteristics such as a notable rate capacity (130 mAh g −1 at 3C, where 1C equals 200 mA g −1 ) and excellent cycling retention (85.4% after 100 cycles at 0.5C) is introduced. Employing electrochemical differential analyses, the contributions to the superior performance arising from the Mn- and O-redox processes are quantitatively delineated. The optimized performance of NLMTO is attributed, in part, to the enhanced stability of both bulk and interface structures. The introduction of Ti through substitution not only contributes to this stability but also allows for the fine-tuning of the material's electron configurations. This is achieved by augmenting the density of states near the Fermi energy level, as well as elevating the O 2p and Mn 3d orbits. This research advances sodium-ion battery technology.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2014
·
IF 2.726
Wei Cai,Chunlin Fu,Rongli Gao,Weihai Jiang,Xiaoling Deng,Gang Chen
Ti-doped bismuth ferrite thin films were prepared via sol–gel spin-coating method. The effects of titanium on the microstructure, optical, leakage, ferroelectric and photovoltaic characteristics have been investigated systematically. The result shows that bismuth ferrite thin films doped with 0–8 at.% Ti are rhombohedral distortion perovskite structure. The addition of titanium inhibits the grain growth and enhances the thickness uniformity and can decrease the band gap of bismuth ferrite thin films. The leakage current of bismuth ferrite thin films is effectively reduced by adding a certain amount of titanium and the leakage mechanism has been investigated. Addition of titanium increases the remnant polarization of the films. As titanium content increases, the short circuit photocurrent density decrease first and then increase, while the open circuit photovoltage increase first and then decrease. The power conversion efficiency of Ti-doped bismuth ferrite thin films increases as titanium content increases, which can be explained as a result of the increased remnant polarization and decreased band gap.
研究领域:
材料科学
·
光伏技术
·
物理学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Junyan Zhang,Jiaqi Shen,Haomin Chu,Yingchun Xie,Zhenzhen Jiang,Daolin Gao,Tianlong Deng,Xiaoping Yu
With the rapid development of the new energy industry, the recovery or extraction of lithium from different resources is currently a global research hotspot. In this work, Li 3 V 2 (PO 4 ) 3 was used as the active component for electrochemical extraction of lithium from aqueous solutions. The results showed that although Li 3 V 2 (PO 4 ) 3 exhibited the reversible de-intercalation/intercalation of Li + , it suffered from severe irreversible dissolution loss in aqueous solutions. This problem was successfully solved by titanium doping. The experiments and DFT calculations showed that when the V(2)-site vanadium in Li 3 V 2 (PO 4 ) 3 was replaced by titanium, the resulting material exhibited superhigh cycle stability and lithium extraction rate. After ten cycles of de-intercalation/intercalation, the extraction capacity still reached 11.5 mg·g −1 , and the attenuation was within the error range. Particularly, because of the decrease of the band gap after doping, the electronic conductivity of the material was significantly improved, and the equilibrium time for lithium extraction was within only 5 min, which was more than 10 times faster than that of the conventional LiFePO 4 and Li 2 MnO 4 materials. This work provides a new solution for the green, efficient, and highly stable extraction of lithium from liquid lithium resources.
研究领域:
材料科学
·
电化学
·
新能源技术
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2017
·Vol. 4
·期 11
·1870-1880
·
IF 4.036
Yitong Han,Min Liu,Keyan Li,Qiao Sun,Wensheng Zhang,Chunshan Song,Guoliang Zhang,Z. Conrad Zhang,Xinwen Guo
Titanium in different amounts has been successfully doped into the zirconium-based metal–organic framework UiO-66 via an in situ synthesis method, resulting in a series of hybrid UiO-66-nTi MOFs. These materials maintain a relatively high crystallinity and excellent structural stability. The addition of titanium has a significant effect on the crystal size and morphology of UiO-66. The UiO-66-nTi MOFs exhibit a sphere-like crystal morphology with a smaller crystal size and a rougher surface compared to the octahedral UiO-66 crystals. The framework order and porosity of the UiO-66-nTi MOFs decrease slightly due to titanium doping. The UiO-66-nTi MOFs were studied as adsorbents for the removal of an organic dye from water. The results demonstrate that these hybrid materials have enhanced adsorption capacity for the organic dye Conge red in comparison with the parent UiO-66. UiO-66-2.7Ti with 2.7% titanium doping shows the highest adsorption capacity of 979 mg g−1, which is three times higher than that of the parent UiO-66. The strong electrostatic attraction between the positively charged surface of UiO-66-2.7Ti and the negatively charged Congo red molecules was identified as the main driving force for the high adsorption capacity.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2023
·Vol. 25
·期 15
·2271-2279
·
IF 3.1
Jingwen Hou,Bernard A. Goodman,Yuchen Lu,Qunyue Zhang,Bin Huang,Long Chen,Shoulei Xu,Wen Deng,Dingkang Xiong
Synthetic Ti-doped delafossite (CuFe1−xTixO2) was prepared by solid state reaction of Fe2O3, CuO and TiO2, and crystals were successfully prepared by the optical floating zone method using a modified experimental protocol that produced crystals in <10% of the time used in previous work. The effects of Ti on the microstructure and magnetic properties of CuFeO2 were investigated. The nonlinear change of cell size may be the result of Ti4+ reduction to Ti3+. However, the Fe oxidation state was not affected by Ti doping, although some oxidation of Cu+ to Cu2+ was observed with the highest Ti contents. The two characteristic magnetic transition temperatures of CuFeO2 occurred at 17 K (TN1) and 11 K (TN2) in the undoped crystal, and these increased to 51 K and 20 K, respectively, in the crystal with x = 0.007, although there was no major change in the two magnetic transition temperatures in crystals with other doping concentrations. In an applied magnetic field of 500 Oe, the magnetization of the x = 0.007 sample was 22 times that of CuFeO2, and its magnetization curve shows the coexistence of regions with ferrimagnetic and antiferromagnetic properties. Furthermore, magnetic hysteresis loops revealed that the saturation magnetization (M) of the sample x = 0.007 is 4.15 emu g−1, but at higher Ti concentrations the M–H curves returned to pairwise linear temperature dependence. Overall, crystals of synthetic delafossite with greatly affected magnetic properties can be prepared by doping with a limited range of Ti contents.
研究领域:
材料科学
·
固体物理学
✓ 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）