MATERIALS RESEARCH BULLETIN
·
2017
·
IF 2.446
Xiao-yu Sun,Chang Liu,Zheng Chen,Yong-qing Ma
In order to reveal the effects of dopant average valence on the photocatalytic performance, Ta and Rh co-doped Ti 0.96 Ta 0.04−x Rh x O 2 (x = 0, 0.008, 0.016, 0.02, 0.024, 0.032, and 0.04) samples were crystallized at 450 °C and 800 °C, respectively; then the 800 °C crystallized x = 0.02 sample was subsequently reduced in the H 2 /N 2 mixture gases at 600, 700, 800, and 900 °C. Under different processing conditions, Ta remains the valence of +5, while the valence of Rh varies. Rh exhibits Rh 3+ and Rh 4+ in the 450 °C crystallized samples and is completely oxidized to Rh 4+ in the 800 °C crystallized samples. In the reduced samples, Rh exists in the forms of Rh, Rh 3+ and Rh 4+ . The optimal photocatalyst is obtained as the ratio of Rh 3+ /Rh 4+ is 2.11 or the average valence of doped Ta and Rh is closest to the +4 valence of substituted Ti.
研究领域:
材料科学
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化学
·
催化
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产品关联
DOI
高影响因子
iScience
·
2025
·
IF 4.1
Hong Qian,Binxia Yuan,Yuhao Liu,Li Wang,Rui Zhu,Pengyu Dong
TiO 2 has low photocatalytic activity due to its easy recombination of photogenerated charges and low visible light utilization efficiency. This study utilized the keto-enol tautomerism principle of fructose in an alkaline environment to successfully obtain Cu 2 O/TiO 2 (CT), Cu 2 O/TiO 2 /Cu (CTC), and TiO 2 /Cu (TC) catalysts. As Cu(I) transformed into Cu(0), the bandgap narrowed, significantly enhancing visible light absorption. Photocatalytic tests showed that CT-0.15 exhibited the highest hydrogen production rate (279.53 μmol g −1 h −1 ), which was 25.18 times higher than that of TC-2. However, CTC-1 had the highest CO production rate (10.58 μmol g −1 h −1 ). Optoelectronic test revealed that CT-0.15 and CTC-1 had higher separation efficiency of photogenerated exciton. Density functional theory (DFT) calculations indicated that the change in the valence state of Cu influenced the reaction mechanism, with CT being favorable for the adsorption of H + in HER and CTC promoting the adsorption of CO 2 in carbon dioxide reduction reaction (CO2RR).
研究领域:
材料科学
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环境科学
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产品关联
DOI
PubMed
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2014
·Vol. 30
·期 12
·3245-3250
·
IF 1.353
Guo Xuena,Liu Wei,Bai Xuejing,He Xiuping,Zhang Borun
High-performance liquid chromatography was used to separate Cr(III) and Cr(VI) in samples with detection by inductively coupled plasma mass spectrometry(ICP-MS). The separation was achieved on a weak anion exchange column. The mobile phase was pH 7.0 ammonium nitrate solution. The redox reaction between Cr(III) and Cr(VI) was avoided during separation and determination. This separation method could be used to separate the samples with large concentration differences between Cr(III) and Cr(VI). The alkaline digestion was used to extract chromium in solid sample, which had no effect on the retention time and the peak area of the Cr(VI). However, the conversion of Cr(VI) from Cr(III) was observed during alkaline digestion, which displayed positive relation with the ratio of Cr(III) and Cr(VI) in samples. Both Cr(III) and Cr(VI) contents of chromium yeasts cultured in media with different chromium additions were determined. The spike recoveries of Cr(VI) for chromium yeasts were in the range of 95–108 %.
研究领域:
分析化学
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环境科学
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生物化学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
·
IF 24.319
Zesheng Deng,Songchang Hu,Jiahui Ji,Shiqun Wu,Haijiao Xie,Mingyang Xing,Jinlong Zhang
Cu is widely used to prepare high-value products in photocatalytic CO 2 reduction reaction (CO2PR). The valence state of transition metals usually has a great impact on the catalytic process. However, the research on Cu valence in CO2PR is lack for its complex valence change. In current work, Cu x /P25 with stable Cu valence composition in CO2PR is prepared. The results show that Cu is composed of Cu 0 and Cu 2 O, and their proportions change regularly as Cu loading changing, which are linearly related to the selectivity of the corresponding products of CO2PR. Combined with thermodynamic and kinetic analysis, the CO adsorption and activation on the surface of Cu 0 and Cu 2 O are considered to be the key to determine the product of CO2PR, which is further confirmed by DFT calculation. Cu 0 and Cu 2 O are proved to be active site of producing CH 4 and CO, respectively. In this case, a reference for the study of highly selectivity Cu based photocatalysts is provided.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Yiping Wu,Meng Wu,Shiwei Yang,Cong He,Chunwen Ye,Yanjie Zhang
Herein, a series of Mn-activated ZnGa2O4 (ZGO) phosphors have been developed for multifunctional applications. The characteristic green and red emission at 503 and 668 nm of Mn-activated ZGO phosphors can be observed under excitation of 247 and 375 nm, respectively, attributed to the partial oxidation of Mn2+ ions resulting in the coexistence of Mn2+ and Mn4+ ions in the host lattice. The valence modulation of Mn content not only realizes the adjustment of red and green luminescence intensity but also achieves the management of persistent luminescence time and thermo-luminescence time. Further, the codoping of Mg2+ could transform the position occupancy preference of Mn and effectively facilitate the conversion of Mn2+ to Mn4+, leading to the regulation of the valence state of manganese ions. Surprisingly, the existence of Mg2+ ions broadens the emission band of Mn4+ and enhances the photoluminescence intensity to 3.8 times, which can be ascribed to the weakened crystal field leading to the downward shift of the 4T2 energy level and the increase of Mn4+ concentration. For this valence modulation behavior, two different hypotheses about the occupancy of Mg2+ have been proposed to explain the corresponding phenomenon. Finally, the potential applications of the synthesized phosphors have been explored in advanced anticounterfeiting strategies, information storage, and plant lighting field.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2025
·
IF 5.1
Siyu Wu,Xiaojuan Niu,Jiali Chen,Wangni Meng,Han Tao,Jianli Zhou,Yuangen Wu
Kanamycin (KAN) can generate a serious threat to human health due to its tendency to accumulate in food. Current colorimetric strategy for KAN detection still faces some challenges, and nanozyme-based colorimetry is an ideal alternative approach. Herein, a non‑copper-based multivalent laccase mimic named Mn-Car is first synthesized through a self-assembly of manganese ions and the endogenous biomolecule carnosine, which is further used to develop a novel colorimetric method for ultrasensitive and selective detection of KAN. The laccase-like catalytic center is formed through the multidentate chelation bonds between manganese ions and imidazolium groups of histidine as well as carboxyl groups of β-alanine in carnosine. The multivalent oxidation states of manganese dynamically regulate electron transfer pathways through synergistic coordination. The unique Mn-Car architecture drives the efficient generation of superoxide radicals (O 2 · − ) and semiquinone radicals (SQ· − ). Leveraging the excellent laccase-like activity of Mn-Car , a highly sensitive colorimetric method for KAN detection is developed. Mn-Car forms polydentate chelation with the amino and hydroxyl groups in KAN, which can trigger multi-step cascade oxidation reactions that disrupt the structural core of Mn-Car and lead to reduced colorimetric signals. The colorimetric method achieves a limit of detection (LOD) of 0.102 μM and is successfully applied for on-site detection of KAN in water samples and honey, providing a novel platform for antibiotic residue analysis.
研究领域:
分析化学
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纳米技术
·
生物传感
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
·
IF 8.1
Jing Ding,Chenhui Qiu,Zhiqiang Zhang,Qinghua Qu,Cheng Fang,Jinfeng Zhang,Guofeng Guan,Hui Wan
Manipulating the oxidation states of transition metals is an ideal solution to achieve selective generation of different products and copper is widely used in CO 2 photocatalytic reduction to methanol. However, the understanding on the effects of valence states of copper species in SrTiO 3 on its structure and the selectivity of the corresponding product in CO 2 photocatalysis are currently still limited. Here, copper-doped SrTiO 3 nanofibers with different controllable ratios of Cu + /Cu 2+ and Cu + /Cu 0 were prepared by the combination of the electrospinning with the in-situ reduction method. The proportion of copper with different valence states (Cu + /Cu 2+ and Cu + /Cu 0 ) was changed by rationally adjusting the time of hydrogen reduction. The presence of monovalent copper facilitated the generation of reactive intermediates, thereby enhancing its photocatalytic activity. The copper-doped SrTiO 3 nanofibers obtained after 3 h of hydrogen reduction (STCu 0.08 -H-3 h) had the highest proportion of Cu + /Cu 2+ and Cu + /Cu 0 with the highest methanol yield (6.96 μmol·g −1 ·h −1 ). Methanol generation rate and Cu + /Cu 2+ ratio of STCu 0.08 -H-xh (x = 1, 2, 3, 4,5) with different hydrogen reduction time were proven to be linearly positively correlated. Furthermore, theoretical investigation and in-situ CO 2 infrared spectrum deeply understood the difference of CO 2 adsorption behavior and CO 2 activation over Cu 2+ and Cu + of STCu 0.08 -H-3 h photocatalyst and the reaction intermediates involved in the photocatalytic CO 2 reduction to methanol.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
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2022
·
IF 5.436
Shuai Huang,Mengmeng Shang,Yu Yan,Peipei Dang,Jun Lin
Co-doping mixed-valence Eu2+/3+ in a single-phase phosphor is an efficient method to realize the emission color regulation, which holds great potential for anticounterfeiting and ratiometric temperature sensing. Here, the mixed-valence Eu-doped Sr1.95+xLi1–xSi1–xAlxO4F (0 ≤ x ≤ 0.25) phosphors were designed and prepared under a reducing atmosphere. The correlation of local phase structures and luminescence properties was discussed. Replacing Si4+–Li+ ion pairs with Al3+–Sr2+ ion pairs compresses the Sr sites occupied by Eu2+, and it stabilizes Eu3+ in a reducing atmosphere and leads to the coexistence of Eu2+ and Eu3+ in single-phase Sr1.95+xLi1–xSi1–xAlxO4F:0.05Eu (0 ≤ x ≤ 0.25) phosphors. Based on the wavelength-dependent luminescence color behaviors of Sr1.95+xLi1–xSi1–xAlxO4F:0.05Eu phosphors, the fluorescent anticounterfeit papers/patterns containing Sr1.95+xLi1–xSi1–xAlxO4F:0.05Eu phosphors were the same as ordinary paper under ambient conditions. However, the hidden colors or images can be read out with green-orange luminescence under 365/300 nm light excitation. Benefiting from the diverse thermal response emission behaviors of Eu2+ (530 nm) and Eu3+ (703 nm), Sr1.95+xLi1–xSi1–xAlxO4F:0.05Eu phosphors exhibit temperature sensing performances, with the maximum absolute and relative sensitivity being 0.0294 K–1 at 573 K and 0.83% K–1 at 348 K. More importantly, Sr1.95+xLi1–xSi1–xAlxO4F:0.05Eu phosphors showed excellent stability in humid, acid, and alkali environments, which contributed to applying mixed-valence Eu2+/3+-doped Sr1.95+xLi1–xSi1–xAlxO4F to the fields of multicolor anticounterfeiting and noncontact optical thermometry.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 11
·3864-3871
·
IF 4.099
Aolei Gao,Zhenhua Sun,Shaopeng Li,Xinjuan Hou,Huiquan Li,Qisheng Wu,Xinguo Xi
Li1.6Mn1.6O4 is a representative ion sieve material that is used to recover lithium from salt brines and bitterns owing to its high lithium ion adsorption capacity reaching 11.9–44 mg g−1. However, manganese dissolution during acid treatment hinders the industrial application of the material. For investigating the mechanism of manganese dissolution, the precursor Li1.6Mn1.6O4 and ion sieve H1.6Mn1.6O4 were prepared and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), chemical content analyses, diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS). The results of XRD, SEM, and FT-IR showed that the bulk phase of Li1.6Mn1.6O4 retained the spinel structure, whereas the lattice diminished during acid treatment. The results of chemical content analyses showed that the bulk phase of Li1.6Mn1.6O4 contained a few trivalent manganese atoms and that the mean valence of manganese in the material increased during acid treatment. DRIFTS and XPS exhibited that the surface of Li1.6Mn1.6O4 was mostly full of tetravalent manganese and retained the spinel structure during acid treatment. In the proposed mechanism of manganese dissolution, an electron of trivalent manganese in the bulk phase transfers to the surface and is captured by tetravalent manganese within the acidic environment. Then, tetravalent manganese is converted to bivalent manganese after acquiring sufficient electrons, and dissolution occurs simultaneously.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Huiyi Zhang,Zeming Wang,Zhe Wang,Liang Wang,Yong Wang
Hydrogen peroxide (H2O2) is a worthy chemical substance with comprehensive applications, but its practical industrial methods involve complex and energy-consuming procedures. Electrocatalytic oxygen reduction for the production of H2O2 is a flexible alternative strategy, which requires a low-cost catalyst with high activity and selectivity for the 2e– ORR pathway. Here, we first present a straightforward and universal one-step hydrothermal method that directly combines Cr-ABIm with commercial carbon black (BP2000) to prepare H2O2 electrochemically with high selectivity and energy saving. A variety of characterization analyses display that the introduction of Cr-ABIm increases the number of defects and active sites and also enlarges the surface area of the catalyst for electrochemical reactions. Importantly, the valence state of Cr is changed (Cr3+ of Cr-ABIm converted to Cr5+) when Cr-ABIm anchors on BP2000, which accelerates the activity of the reduction reaction. The selectivity of the catalyst for H2O2 preparation is also determined by Koutecky–Levich analysis and rotating ring disk electrochemical tests. In a potential range of 0.2–0.7 V (vs reversible hydrogen electrode (RHE)), the electron transfer number of the Cr-ABIm@BP2000 catalyst is on the verge of 2.5, and the electrogenerated yield of H2O2 is 65%. In addition, its mass activity at 0.5 V is up to 7.56 A g–1. Density functional theory (DFT) calculations clarify that suitable N, O coordination on the active surface of BP2000s acquires the changing capacity of the valence state of Cr, thereby regulating the adsorption of intermediate products and endowing it with superior H2O2 performance. It is believed that Cr-ABIm@BP2000 will be a viable electrocatalyst for sustainable in situ generation of H2O2 from oxygen.
研究领域:
化学
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2021
·
IF 3.196
Jingyan Zhu,Baolin Liu,Weibing Zhang,Jun Jiang,Xinhua Li
Single-molecule magnets in cobalt clusters is much less well known than it is in manganese(II)/(III)/(IV) clusters. To explore new types of cobalt clusters and their potential applications, a new mixed valence coordination polymer ([Co(III) 3 Co(II) 2 (mba) 6 (Hdtba) (H 2 O) 4 ] n , H 2 dtba=2,2’-dithiodibenzoic acid, H 2 mba=2-mercaptobenzoic acid) ( 1 ) is constructed by employing cobalt chloride hexahydrate and H 2 mba as starting reactants under hydrothermal conditions. Single-crystal XRD studies indicate that 1 consists of a trinuclear cobalt(III)-sulfur cluster moiety and two discrete cobalt(II) nodes, which result in the formation of a covalent three-dimensional complex network. Similarly, the cobalt(III) cluster moiety acts as a building unit in this infinite coordination polymer 1 instead of the discrete and tiara-like clusters previously reported in the literature. Magnetic studies show its slow magnetic relaxation in the absence of an applied dc field, which is characteristic behavior of single-ion magnets, caused by the individual Co(II) ions.
研究领域:
无机化学
·
材料科学
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产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Binghong Wu,Baoqian Yang,Xinru Wu,Dong-Hau Kuo,Zhengjie Su,Longyan Chen,Pengkun Zhang,Mengistu Tadesse Mosisa,Dongfang Lu,Zhanhui Yuan,Jinguo Lin,Xiaoyun Chen
Nitrogen fixation reaction via photocatalysis offers a green and promising strategy for renewable NH3 synthesis, and catalysts with high-efficiency photocatalytic properties are essential to the process. Herein, we demonstrate a W-doped Sb2OS2 bimetal oxysulfide catalyst (labeled as SbWOS) with abundant oxygen vacancies, heterovalent metal states, and hydrophilic surfaces for nitrogen photoreduction to ammonia. The SbWOS-3 with suitable W-doping exhibited excellent nitrogen fixation activity of 408.08 μmol·g–1·h–1 and an apparent quantum efficiency (AQE) of 1.88% at 420 nm and a solar-to-ammonia (STA) conversion efficiency of 0.082% in pure water under AM1.5G light irradiation. The W-doping not only transforms hydrophobic Sb2OS2 into a hydrophilic catalyst, making it easier for H2O molecules adsorbed on the SbWOS surface and catalyzed into protons, but also endows the SbWOS catalyst with rich oxygen vacancies, acting as the active sites for trapping and activating the N2 molecule, and for trapping and activating H2O to produce the protons for the N2 photocatalytic reduction reaction. The hydrazine drives the SbWOS catalyst with the heterovalent metal states, which acts as the photogenerate electrons quickly hopping between W5+ and W6+ to transfer for the N2 reduction reaction. This study provides a feasible scheme for applying oxygen vacancy defects, heterovalent metal states, and surface hydrophobic-to-hydrophilic wetting engineering in bimetal oxysulfide for N2 photoreduction to ammonia.
研究领域:
材料科学
·
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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