查找使用阿拉丁产品的科研文献

Significantly enhanced photoelectrochemical cathodic protection performance of hydrogen treated Cr-doped SrTiO3 by Cr6+ reduction and oxygen vacancy modification

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.

Au nanoparticles decorated SrTiO3−x hollow structure for plasmatic enhanced hydrogen production in UV–visible and near-infrared region

Meng Liu,Xiangyu Xu,Wanying Xiao,Yipeng Liu,Yongbo Cui,Haojie Zhang,Amin Ju,Bo Feng,Lijing Wang,Weilong Shi

Designing photocatalysts with a broad reaction to sunlight is crucial for efficient clean energy conversion. However, most catalysts reported so far can only respond to UV and visible light for photocatalysis, neglecting the utilization of near-infrared light, which accounts for almost 50 % of sunlight. In this study, we obtained Au nanoparticles (NPs) decorated porous hollow SrTiO 3 material rich in oxygen defects using an acid etching-assisted hydrothermal method. The formation of a Schottky heterojunction between Au and SrTiO 3−x with matched Fermi levels enhances the electron transfer ability of SrTiO 3−x . Additionally, Au NPs exhibit two types of surface plasma resonance (SPR) effects at 480 nm (transverse SPR) and 800 nm (longitudinal SPR in the near-infrared region) by absorbing specific photons emitted by SrTiO 3−x . The "hot" electrons of the photoexcited SPR state can be further injected into the CB of SrTiO 3−x . Furthermore, the local electromagnetic field around the SPR-enhanced Au NPs effectively promotes the excitation and transfer kinetics of photoelectrons, allowing more "hot" electrons to participate in the photocatalytic reaction. Besides, the unique hollow porous structure of the catalyst ensures multiple reflections of sunlight within SrTiO 3−x . As a result, the hydrogen production efficiency of Au-SrTiO 3−x under near-infrared (NIR) and UV–vis-NIR light irradiation reaches 850 and 3206 μmol h −1 g −1 , with apparent quantum efficiency of 6.4 % and 7.2 % at 820 nm and 420 nm, respectively. The possible photocatalytic mechanism was proposed based on thorough systematic experimental analysis and theoretical calculations.

Synthesis of SrTiO3-TiO2-CaTiO3/Cu2O composite for stable and efficient H2 generation in deionized water and river water

Junfeng Yang,Jinsong Lu,Liangsheng Xie,Jingfeng Wu,Yu Wen,Qin Zhang

Herein, the SrTiO 3 -TiO 2 -CaTiO 3 /Cu 2 O quaternary composite has been designed and prepared via one-step hydrothermal process followed by a NaBH 4 reduction treatment. By comparing the H 2 production rate (HPR) of Sr-Ti-Ca/Cu samples prepared by different Cu sources, it is found that Sr-Ti-Ca/Cu has the best H 2 production performance when CuCl 2 is as Cu source. As expected, the highest HPR of Sr-Ti-Ca/Cu sample is up to 5.088 mmol g −1  h −1 , which is 195.7 times as higher as that of the Sr-Ti-Ca sample (0.026 mmol g −1  h −1 ) under the same conditions. Moreover, the HPR reached 0.692, 0.530 and 0.647 mmol g −1  h −1 in tap water, lake water and river water, indicating that the photocatalyst has high practicability in natural water sources. In addition, the experiment of the tap water composition effect on H 2 production performance shows that NO 3 − and SO 4 2− ions have great negative influence on the HPR. Compared with Sr-Ti-Ca, the light absorption of Sr-Ti-Ca/Cu extends over the entire visible region, the interface resistance decreases, and the photocurrent density increases. These results suggest that the well-designed dual p-n heterojunctions and dual type-II heterojunctions in Sr-Ti-Ca/Cu sample can enhance the light absorption in the ultraviolet region and realize the rapid separation and migration of photogenerated charge, thereby accelerating the production of H 2 . This work shows the strong advantage and potential of non-precious metal efficient photocatalyst system for producing H 2 from deionized water and natural fresh water.

Transparent, low dark current, fast response ultraviolet and short-wavelength blue photons photodetector based on Graphene/SrTiO3 single crystal

Lujia Cong,Huimin Zhao,Yurui Han,Shan Zhang,Chunyue Gao,Ziwen Cheng,Jiben Yang,Hongbin Wang

Ultraviolet light and short-wavelength blue photons (UV-SWB) can cause damage to the human body under excessive exposure. Strontium titanate (SrTiO 3 ), which is a crucial perovskite oxide with a direct energy band gap of ∼3.2 eV, has great potential for UV-SWB photodetection . In this work, UV-SWB photodetector with high transparency based on Graphene/SrTiO 3 heterojunction was fabricated by graphene transfer method. The Graphene/SrTiO 3 photodetector exhibits an ultra-low dark current of 6 pA at a 30 V bias. The response spectrum of the Graphene/SrTiO 3 photodetector was 220–410 nm, covering the UV-SWB band. Under 385 nm light irradiation, the photodetector exhibits a response of 3.4 mA/W, a detectivity of 1.5 × 10 10 Jones, a response time of 186 ms, and a light-to-dark current ratio of 10 3 magnitude at a 30 V bias. In addition, the transmittance of the photodetector in the visible light band reaches 80 %, which has excellent visualization performance. The excellent performance of Graphene/SrTiO 3 photodetector is attributed to the high crystal quality of SrTiO 3 wafer and the van der Waals interface constructed by Graphene/SrTiO 3 reduces the bulk defect density and interfacial state density, which could be beneficial the separation and transport of photogenerated carriers in the active layer and heterojunction . This study has important reference value for the design and manufacture of UV-SWB photodetectors.

Large electrostrain achieved by the regulation of phase structure in Ba(Zr0.5Ti0.5)O3-Modified Bi0.5Na0.5TiO3–SrTiO3 lead-free ceramics

Xinyu Chen,Xinyu liu,Taotao Ai,Qian Qiu,Minghui Hao,Yang He,Minghui He,Haoyu Wang,Chunlin Song,Daniel Q. Tan,Gang Liu,Yan Yan

Herein, a series of lead-free ceramics, (1− x )(0.78Bi 0.5 Na 0.5 TiO 3 –0.22SrTiO 3 )– x Ba(Zr 0.5 Ti 0.5 )O 3 (abbreviated as BNST–BZT), were synthesized via the conventional solid-state reaction approach. The effects of introducing the BZT component on the electromechanical transformation properties and phase transition of BNST were thoroughly investigated, leading to the development of a corresponding phase diagram. The addition of BZT significantly influenced phase transitions and domain structures, with phase coexistence involving ferroelectric rhombohedral and relaxor tetragonal phases. XRD analysis and temperature-dependent measurements of dielectric and ferroelectric properties demonstrated that the relaxor phase content could be modulated by adjusting the BZT content and varying the temperature. Domain changes were also observed through PFM testing. With the addition of BZT, the RE-FE phase transition temperature T F-R is successfully adjusted to near room temperature, accompanied by the disruption of long-range ferroelectric domains and the formation of polar nanoregions. This transition marks a shift from NR to ER state. Specifically, with an optimized BZT content of 0.006, the material demonstrates a significant strain of 0.41 % under a 70 kV/cm and achieves a maximum normalized strain of 715 p.m./V at 50 kV/cm. This research introduces an effective doping strategy that offers valuable insights into the design and development of high-performance lead-free ceramics. Additionally, it investigates the mechanisms underlying the observed high strain responses, highlighting their potential application in lead-free piezoelectric actuators.

Defect-mediated Q×f degradation and near-zero temperature coefficient of resonant frequency in CeO2-SrTiO3 microwave dielectric ceramics

Zhijian Wang,Lizi Chen,Baoyu Wang

(1- x )CeO 2 -xSrTiO 3 ( x = 0.04-0.10) ceramics were prepared by the conventional solid-state reaction method, and their phase constitution, microstructure, defect behavior, and microwave dielectric properties were systematically investigated. XRD combined with Rietveld refinement confirmed a two-phase composite of cubic CeO 2 and SrTiO 3 , and EDS mapping provided direct evidence of Sr-Ce cation interdiffusion across the phase boundaries. The relative density and ε r increased with both SrTiO 3 content and sintering temperature. For the x = 0.04 composition sintered at 1550 °C, a near-zero τ f (+6.5 ppm/°C), ε r ≈ 25.21, and a maximum Q×f (∼20,540 GHz) were obtained. However, increasing the sintering temperature to 1600 °C increased the relative density to ∼95.7% and the mean grain size from 2.98 to 4.15 μm but reduced Q×f to ∼13,588 GHz, indicating that the variation of Q×f does not follow the density trend. EPR, XPS and ac conductivity analyses showed that oxygen-vacancy-related defects and grain-boundary barrier-layer conduction contribute significantly to the Q×f degradation, whereas the increasing SrTiO 3 phase fraction, its intrinsically low Q×f , residual porosity and grain size also play a role. This work identifies defect migration and interfacial electrical heterogeneity as important contributors to the Q×f variation in CeO 2 -SrTiO 3 composite ceramics.

Ion selection criteria for effective A/B site co-doping in SrTiO3: achieving comprehensive dielectric performance via synergistic pinning effect

Yuhang Zhang,Yanzhao Zhang,Meiling Yang,Kunpeng Lin,Zhe Zhao,Ning Xie,Guoxiang Zhou,Yang Zhihua,Dechang Jia,Yu Zhou

Microwave dielectric ceramics with a high dielectric constant and low dielectric loss are essential for 5   G/6   G miniaturized communication devices; however, inherent property trade-offs hinder further performance optimization. Although A-site rare-earth or B-site composite ion doping has been employed to address this challenge in perovskites, overall performance remains limited by suboptimal A-site selection and B-site ionic mismatch. Here, we synthesized compositionally varied Sr 1-1.5 x Ce x Ti 0.98 (Zn/Mg 1/3 Nb 2/3 ) 0.02 O 3 materials through selective Ce and Zn/MgNb co-doping to simultaneously overcome sintering and dielectric performance challenges. Incorporation of small-radius A-site Ce provides additional solid-solution space for large-radius B-site Zn/MgNb, effectively promoting a single-phase composition and dense microstructure. Crucially, the valence transition of Ce, combined with its synergistic electron-pinning effect with Zn/MgNb, immobilizes free electrons and significantly suppresses Ti 4+ reduction. This synergistic interaction enhances the quality factor beyond 14,000   GHz, surpassing the Q×f values reported in previous studies. Additionally, the controlled reduction in ionic polarizability, coupled with enhanced octahedral distortion, maintains the dielectric constant above 115 while reducing the temperature coefficient from +1400 ppm/°C to +259 ppm/°C. At a doping level of 0.30, the co-doped material exhibits superior comprehensive properties: ε r = 123.9, Q×f = 14,447   GHz, and τ f = +337 ppm/°C. This study highlights the considerable potential of rational co-doping strategies to enhance material performance.

Defect-Driven TiO2– x /SrTiO3– x Heterostructure with Ferroelectricity Enables Shuttle Suppression and Dendrite-Free Growth

Dongqi Fan,Zicheng Wang,Yuan Tian,Cheng Wang

Abstract The inherent Li dendrite growth, notorious shuttle effect, and severe redox reaction kinetics of lithium polysulfides (LiPSs) impede the feasibility of practical development of lithium–sulfur (Li–S) batteries. Herein, a bi-functional defect-rich TiO2–x/SrTiO3–x nanocube, embedded in a N-doped carbon (NC) freestanding fabric, was prepared and effectively used as a sulfur host and an interlayer between the separator and lithium anode for Li–S full batteries. The spontaneous formation of a built-in electric field (BIEF) between TiO2–x and SrTiO3–x guides self-driven charge rearrangement, resulting in strong directional LiPS migration to boost sulfur redox kinetics and fast, uniform Li+ transfer to avoid Li dendrite growth. Meanwhile, the introduction of oxygen vacancies can induce a ferroelectric phase and provide more active sites for lithium/sulfur storage. The whole 3D framework, enabled with fast electron/ion transport, reduces the Li nucleation overpotential and lowers the energy barrier for LiPS conversion. Consequently, Li||Li cells with the TiO2–x/SrTiO3–x@NC interlayer cycled stably over 600 h at 5 mA cm–2 and 5 mAh cm–2. Furthermore, Li–S full batteries delivered 1285 mAh g–1 at 0.1 C with merely 0.074% per-cycle capacity decay. Our findings emphasized the efficacy of a defect-rich TiO2–x/SrTiO3–x ferroelectric heterostructure implanted into a 3D conductive framework.

Synergistic charge redistribution at SrTiO3@NH2-MIL-125 S-scheme heterostructure: steering photogenerated reactive species for efficient NO-to-nitrate conversion

Wenrui Dai,Chenxiang Wang,Jiajia Gao,Haotong Ma,Yingchun Miao,Shuo Wang,Zhanshuo Tao,Shuning Xiao

Tunable self-powered n-SrTiO3 photodetectors based on varying CuS-ZnS nanocomposite film (p-CuZnS, p-CuS, and n-ZnS)

Yong Zhang,Xiaojie Xu,Xiaosheng Fang

The heterojunction photodetector between n-SrTiO 3 (n-STO) and p-CuS-ZnS (p-CZS) is prepared by a simple chemical bath deposition. The p-CZS/n-STO photodetector exhibits excellent self-powered characteristics under 390-nm light illumination, including high photosensitivity (on/off ratio of 300), fast response speed (0.7/94.6 ms), and good wavelength selectivity (410-380 nm). More importantly, the self-powered n-STO photodetectors can be regulated by varying the composition of CZS film (p-CZS, p-CuS, and n-ZnS). All devices exhibit a large open-circuit voltage and show different self-powered behaviors because of the different built-in electric fields. The open-circuit voltages of the CZS/STO, CuS/STO, and ZnS/STO devices are measured to be 0.56, 0.30, and 0.35 V, respectively. This work provides a simple and effective way to fabricate tunable self-powered photodetectors by varying the composition of the nanocomposite film.

A unique octadecahedron SrTiO3 perovskite oxide with a nano step-shaped facet structure for enhanced photoredox and hydrogen evolution performance

Chuyu Wang,Yan Li,Xiaojiao Cai,Dongping Duan,Qibo Jia

As a typical perovskite-type crystal, strontium titanate (SrTiO3, STO) has remarkable photocatalytic activity and is broadly used in solar-driven overall water splitting. The research on controlling the synthesis of polyhedral STO with different exposures of crystal facets to obtain different optoelectronic properties has been greatly carried out in recent years. However, there are few reports of research on the construction of a nano step-shaped facet structure by the reconstruction of the STO crystal facet at a certain temperature, and the formation mechanism and composition analysis have not been explained clearly. In particular, the influence of crystal surface recombination on the hydrogen production reaction hasn't been thoroughly studied. This work presents the existence of a novel STO with the nano step-shaped facet structure parallel to (100) and (110) facets based on octadecahedron STO by a solid-state reaction, and the formation has been monitored by thermogravimetric analysis and in situ X-ray diffraction. In addition, more importantly, the step-shaped facet structure is rich in Sr, and lacks O and Ti, which is evidenced by EPR and XPS characterization, and it affects the transfer and separation of photo carriers. The complex STO catalysts were prepared by photodeposition of Rh, Cr, and Co to compare the hydrogen production capacity of overall water splitting. The novel step-shaped facet SrTiO3 has a good deposition effect on the cocatalysts, and the synthesized catalyst can effectively shorten the band gap to 1.92 eV and prolong the photogenerated carriers' lifetime to 3.7356 ns. Consequently, the novel SrTiO3 sample deposited co-catalysts achieve remarkable activity with the highest H2 evolution rate of 172.0 μmol h−1, which is 4.6 times higher than that of the original octadecahedron SrTiO3 prepared by the hydrothermal method. The DFT calculation results prove that the excellent photocatalytic performance is due to the lower work function and effective electron transfer of the SrTiO3 (100) crystal facet and Sr-rich (110) crystal facet, which is verified by the obvious electron transfer between the CrO42− and the two kinds of crystal facets.

Anchoring SrTiO3 nanoparticles on layered ZnIn2S4 to construct S-scheme heterojunctions as novel photocatalysts for efficient degradation of MO dye

Xia Xu,Changchun Chen,Lingxiu Shu,Cheng Cheng,Zhonghai Tang,Yifeng Wang,Lin Pan,Zishen Guan

Water pollution can be efficiently treated by semiconductor photocatalysts under sunlight irradiation. In this study, novel S-scheme SrTiO 3 /ZnIn 2 S 4 composites were successfully fabricated via a facile oil-bath method. And the synthesized samples were then characterized by various characterization techniques together with Density Functional Theory (DFT) calculation. The X-Ray Diffraction(XRD)patterns show that SrTiO 3 /ZnIn 2 S 4 composites are composed of cubic perovskite structure SrTiO 3 and hexagonal phase ZnIn 2 S 4 . The High Resolution Transmission Electron Microscope(HRTEM)and Field Emission Scanning Electron Microscope (FESEM) images showed the intimate contacts between SrTiO 3 and ZnIn 2 S 4 are established to form the heterojunction. The photocatalytic activity of the composite was excellent when degrading organic pollutants, which outperformed that of pristine SrTiO 3 and ZnIn 2 S 4 . The prepared SrTiO 3 /ZnIn 2 S 4 -33% composite sample was proved to have the best photocatalytic activity, with 98 % degradation of organic pollutants under 32 min. The ·O 2 – is the main active reaction species for the degradation of organic pollutants, which was demonstrated by free radical trapping experiment. In addition, the mineralization of organic pollutants during the degradation process was analyzed by Total Organic Carbon (TOC) test. According to a series of experimental and theoretical calculations, the S-scheme heterojunction formed in the SrTiO 3 /ZnIn 2 S 4 composite is put forward for comprehending the photocatalytic degradation of organic pollutants and the formation of free radicals.