JOURNAL OF ALLOYS AND COMPOUNDS
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2021
·
IF 5.316
Xin Yu,Siran Xu,Xian Liu,Xiaohong Cheng,Yeshuang Du,Qi Wu
The development of self-supported nanosheet materials with porous multiple active sites has enormous potential for the application of oxygen evolution reaction (OER). Herein, we reported a three-dimensional (3D) porous nanosphere Mn-NiCo 2 S 4 /NF catalyst for OER. As a result, the simple Mn doping strategy results in good electrocatalytic performance and outstanding stability. During the OER, the Mn-NiCo 2 S 4 /NF only needs a small overpotential of 220 mV (40 mV lower than pure NiCo 2 S 4 /NF) to achieve the current density of 10 mA cm −2 , which is mainly due to a large number of exposed active sites and adequate pathways for mass diffusion and oxygen gas release. Moreover, Mn doping optimizes the electronic structure and thus facilitates electron transport , leading to superior electrocatalytic performance. The catalyst exhibits incredible corrosion resistance in 1 M KOH solution for 60 h or more. This work provides a valuable method to synthesize a low cost, high-efficiency, and corrosion resistant transition metal electrocatalyst for oxygen evolution using heteroatom doping strategy.
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 12
·4181-4195
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IF 6.119
Fan Fu,Yufan Zhang,Yan Zhang,Yuyue Chen
In this experiment, Mn@TiO2 nanofibers in the form of membranes were fabricated by ordinary electrospinning and a higher temperature calcination process. Field-emission scanning, X-ray diffraction analysis, X-ray photoelectron spectroscopy, Raman spectra, UV-visible diffuse spectra, UV-visible spectroscopy, and Brunauer–Emmett–Teller (BET) evaluation were used to characterize the resulting samples. The study revealed that, upon the addition of the manganese ion, the continuous and mechanical properties of the nanofibers and nanofilms were substantially enhanced. Notably, after 60 minutes, the Mn@TiO2-0.10 degradation efficiency reached 94.92% under ultraviolet light, which was 5 times greater than that for TiO2 nanofibers. It was due to the controlled mixture phase and palpable raised specific surface area, which ensured a pronounced enhanced photocatalytic activity of the nanofibers. In addition, the application of nanofibers on the capacitor aspect was explored by electrochemical workstations. The highest photoactivity sample performed mass-specific capacity as high as 5.09 F g−1. Such efficient capacity and higher photoactivity of the photocatalyst shed light on the preparation of soft inorganic materials and their application in energy conversion.
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JOURNAL OF LUMINESCENCE
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2021
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IF 3.599
Zhenxing Fang,Kuang Wu,Le Wang,Da Xu,Weiwei Wang,Yuhang Lin,Xiaohui Liu,Chun Sun
Mn doped two-dimensional (2D) layered perovskites , are becoming excellent candidates as red phosphor because of their high quantum yields (QY) and enhanced stability. However, these Mn doped 2D layered perovskites can only be excited by the near UV light , which largely limits the development of perovskites. Herein, blue-excitable Mn-doped PEA 2 (Pb/Mn)(Br/I) 4 PQDs are synthesized from anion exchange surface engineering strategy. After anion exchange, orange Mn 2+ emission from exciton-to-Mn energy transfer is acquired under the excitation of 450 nm. The PEA 2 (Pb/Mn)(Br/I) 4 compounds exhibit strong luminescence with photoluminescence (PL) QY of 52%, which is comparable to most of the reported red emitting phosphors. A prototype white light-emitting diode (WLED) with good optical performance was fabricated using commercial (Sr,Ba) 2 SiO 4 :Eu phosphor and as-prepared PEA 2 (Pb/Mn)(Br/I) 4 as green and orange color converters, showing great potential in the applications of solid state lighting.
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CHEMOSPHERE
·
2021
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IF 7.086
Han Qiao,Xiaoxiang Wang,Peng Liao,Cheng Zhang,Chongxuan Liu
A novel Mn(II) encapsulated mesoporous silica nanoparticles (Mn-MSNs) was developed for efficiently removing antibiotic tetracycline from aqueous solutions. The material has a well-ordered, hexagonal mesopore structure with a large specific surface area (720 m 2 /g) and maximum sorption capacity (229 mg/g) that is about an order of magnitude higher than that of mesoporous silica nanoparticles without Mn-encapsulated, or encapsulated with other transition metal cations Fe 3+ and Cu 2+ . Sorption results showed that the materials can sequestrate tetracycline within a large concentration range (5 μg/L–450 mg/L). Batch sorption experiment, spectroscopic analysis and density functional theory calculation collectively indicated that Mn–O complexation was the dominant mechanism for the tetracycline sorption. Electrostatic attraction and cation-π interaction also contributed to tetracycline sorption with their contribution levels varying with pH in a synergetic way with the Mn–O complexation. The Mn(II) encapsulated MSNs exhibited a good regeneration property over five repeated sorption-desorption cycles, demonstrating its promising potential in the cost-effective applications of sequestrating tetracycline from wastewater, drinking water , and contaminated solutions.
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Journal of Energy Chemistry
·
2021
·
IF 9.676
Zhiguo Zhang,Hua Huo,Zhenjiang Yu,Lizhi Xiang,Bingxing Xie,Chunyu Du,Jiajun Wang,Geping Yin
Mn doping is deemed as a promising strategy to improve the electrochemical performance of the α-Ni(OH) 2 battery-type supercapacitor electrode. However, the internal structure evolution, the pathways and the dynamics of the proton/intercalated anion migration, as well as the functioning mechanism of Mn dopant to stabilize the layered structure during cycles remain unclear. Here, we unveil that irreversible oxidization of Mn 3+ at the initial CV cycles, which will remain as Mn 4+ in the NiO 2 slabs after the first oxidization to effectively suppress the phase transformation from α-Ni(OH) 2 /γ-NiOOH to β-Ni(OH) 2 /β-NiOOH and further maintain the structural integrity of electrode. With a synergistic combination of theoretical calculations and various structural probes including XRD and 2 H MAS solid state NMR, we decode the structure evolution and dynamics in the initial CV (cyclic voltammetry) cycles, including the absorption/desorption of hydrogen containing species, migration of intercalated anions/water molecules and the change of interlayer space. This present work elucidates a close relationship between doping chemistry and structural reliability, paving a novel way of reengineering supercapacitor electrode materials.
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Molecular Catalysis
·
2020
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IF 3.687
Anwei Wang,WeiYou Zhou,Zhonghua Sun,Zhong Zhang,Zhihui Zhang,MingYang He,Qun Chen
Developing efficient heterogeneous catalytic systems based on easily available materials and molecular oxygen for the selective oxidation of alkylarenes is highly desirable. In the present research, NiMn hydrotalcite (Ni 2 Mn-LDH) has been found as an efficient catalyst in the oxidation of alkylarenes using molecular oxygen as the sole oxidant without any additive. Impressive catalytic performance, excellent stability and recyclability, broad applicable scope and practical potential for the catalytic system have been observed. Mn 3+ species was proposed to be the efficient active site, and Ni 2+ played an important role in stabilizing the Mn 3+ species in the hydrotalcite structure. The kinetic study showed that the aerobic oxidation of diphenylmethane is a first-order reaction over Ni 2 Mn-LDH with the activation energy ( E a ) and pre-exponential factor ( A 0 ) being 85.7 kJ mol −1 and 1.8 × 10 9 min −1 , respectively. The Gibbs free energy (Δ G ≠ ) was determined to be -10.4 kJ mol -1 K -1 for the oxidation based on Eyring-Polanyi equation, indicating the reaction is exergonic. The mechanism study indicated that the reaction proceeded through both radical and carbocation intermediates. The two species were then trapped by molecular oxygen and H 2 O or hydroxyl species, respectively, to yield the corresponding products. The present research might provide information for constructing highly efficient and stable active site for the catalytic aerobic oxidation based on available and economic material.
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NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 4
·2285-2294
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IF 3.591
Nannan Liu,Simin Shang,Dajun Shi,Qingrong Cheng,Zhiquan Pan
Thanks to the unique structure and properties of MOFs, a well-designed novel hollow ZnO/Mn-ZIF-67 composite photocatalyst was synthesized by a facile sonocrystallization approach successfully. The hollow ZnO/Mn-ZIF-67 composites exhibited higher photocatalytic activity in degrading Bismarck brown R than pure hollow ZnO spheres and Mn-ZIF-67. The optimal ZnO/Mn0.5-ZIF-67 showed the highest catalytic activity with 89.5% Bismarck brown R removal within 100 min. The improved photocatalytic activity of the composites could be mainly attributed to effective photogenerated charge separation and transfer through the coupled Z-scheme heterojunction between hollow ZnO spheres and Mn-ZIF-67. The composite photocatalyst exhibited obviously good stability and recyclability after recycling 4 times. Finally, a possible Z-scheme electron transfer mechanism was proposed based on the active radical trapping experiments and ESR which could explain the improved photocatalytic performance of the photocatalytic system. This work provides a promising approach to construct a direct Z-scheme heterojunction for the degradation of environmental pollutants.
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Journal of Physical Chemistry C
·
2020
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IF 4.189
Yubin Zhao,Xiao Zhang,Cong Xie,Wenbin Shi,Ping Yang,San Ping Jiang
Although inorganic cesium halide lead perovskite nanocrystals (NCs) exhibited tunable photoluminescence (PL), it is still a challenge for such NCs with multicolor and white emission for application. In this article, as-synthesized Mn:CsPbCl3 NCs were treated using an oleoamine solution of CdX2 (X = Cl, Br) to get a high PL quantum yield (PLQY) and stability. CdCl2 passivated the surface defects of Mn:CsPbCl3 NCs through anion exchange to get high PL intensity, especially to increase Mn emission. The PLQY of the sample was increased from 15 to 85% after ion exchange. Furthermore, the treatment of CdBr2 resulted in the appearance of a powerful blue emission peak, and the PLQY increased to 95.7%. The PL decay kinetics of samples was studied before and after treatment. Mn2+ emission in Mn:CsPb(Cl/Br)3 NCs was increased because of the reaction of CdBr2 and Mn:CsPbCl3 NCs. Interestingly, the tunable and bright white emission from Mn:CsPb(Cl/Br)3 NCs was obtained by controlling the amount of Br. The controlling of Mn emission plays an important role in changing the Commission Internationale de l’Eclairage color coordinates. Because of bright and tunable PL, the NCs may be used in white-light-emitting diodes.
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Nature Communications
·
2020
·Vol. 11
·期 1
·1-8
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IF 12.121
Feng Jiaqi,Gao Hongshuai,Zheng Lirong,Chen Zhipeng,Zeng Shaojuan,Jiang Chongyang,Dong Haifeng,Liu Licheng,Zhang Suojiang,Zhang Xiangping
Developing effective catalysts based on earth abundant elements is critical for CO 2 electroreduction. However, simultaneously achieving a high Faradaic efficiency (FE) and high current density of CO ( j CO ) remains a challenge. Herein, we prepare a Mn single-atom catalyst (SAC) with a Mn-N 3 site embedded in graphitic carbon nitride. The prepared catalyst exhibits a 98.8% CO FE with a j CO of 14.0 mA cm −2 at a low overpotential of 0.44 V in aqueous electrolyte, outperforming all reported Mn SACs. Moreover, a higher j CO of 29.7 mA cm −2 is obtained in an ionic liquid electrolyte at 0.62 V overpotential. In situ X-ray absorption spectra and density functional theory calculations demonstrate that the remarkable performance of the catalyst is attributed to the Mn-N 3 site, which facilitates the formation of the key intermediate COOH * through a lowered free energy barrier.
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ACS Biomaterials Science & Engineering
·
2020
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IF 4.152
Yijue Wang,Liqing Zou,Zhe Qiang,Jianhai Jiang,Zhengfei Zhu,Jie Ren
Radiotherapy (RT) is a major treatment method for non-small-cell lung cancer (NSCLC), and development of new treatment modality is now critical to amplify the negative effects of RT on tumors. In this study, we demonstrated a nanoparticle-loaded block copolymer micellar system for cancer hyperthermia treatment (HT) that can be used for synergistic therapy under alternating magnetic field (AMF) and radiation field. Block copolymer micelles (polyethylene glycol-block-polycaprolactone, or PEG-PCL) containing hyaluronic acid (HA) and Mn–Zn ferrite magnetic nanoparticles (MZF) were fabricated via a two-step preparation. HA-modified Mn–Zn ferrite magnetic nanoparticles (MZF-HA) can be enriched in CD44 highly expressing tumor cells, such as A549 (human lung adenocarcinoma cell line), through an active targeting mechanism via receptor–ligand binding of HA and CD44 (HA receptor). MZF can generate thermal energy under an AMF, leading to a local temperature increase to approximately 43 °C at tumor sites for mild HT, and the increased tumor oxygenation can enhance the therapeutic effect of RT. In vitro experiments show that MZF-HA is able to achieve excellent specific targeting performance toward A549 cells with excellent biocompatibility as well as enhanced therapy performance under HT and RT in vitro by apoptosis flow cytometry. In the A549 subcutaneous tumor xenografts model, MRI confirms the enrichment of MZF-HA in tumor, and hypoxia immunohistochemistry analysis (IHC) proved the increased tumor oxygenation after HT. Furthermore, the tumor volume decreases to 49.6% through the combination of HT and RT in comparison with the 58.8% increase of the untreated group. These results suggest that the application of MZF-HA is able to increase the therapeutic effect of RT on A549 and can be used for further clinical NSCLC treatment evaluation.
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CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Jing Su,Tao Lyu,Hao Yi,Lei Bi,Gang Pan
A major challenge for effective decontamination of arsenate from aqueous solution is the development of adsorbent possessing enormous high-active sites with strong affinity to realize both high adsorption capacity and reduction of arsenate down to permissive levels. Here we demonstrate that this challenge may be overcome by doping Mn atoms into La 2 O 2 CO 3 materials. The synthesized material (5.26%-MnL) achieved an arsenate capture ability superior to most other currently-reported adsorbents, with the maximum adsorption capacity of 555.6 mg/g. Additionally, this novel adsorbent could dramatically reduce the concentration of arsenate from 3775 μg/L to less than 4 μg/L, well below the acceptable value for drinking water (10 μg/L). The adsorption capacity of 5.26%-MnL was demonstrated to be >300 mg/g over a wide pH range from 4 to 9 and the efficiency was maintained >85% even after three cycles of adsorption/desorption. Through a series of characterizations, both surface complexation and ion exchange were proved to contribute to arsenate removal at low molar ratios of As(V)/5.26%-MnL while forming LaAsO 4 precipitation played a greater role at higher As(V)/5.26%-MnL ratios. Density Functional Theory (DFT) calculations suggested that Mn atoms acted as active species by not only increasing lattice defects and adsorption sites, but also by activating La 3+ in La 2 O 2 CO 3 , which lowered the adsorption energy and facilitated arsenate removal. Due to the high affinity and superior adsorption capacity towards arsenate, Mn-doped La 2 O 2 CO 3 has been demonstrated to be a promising prospect for the remediation of arsenate-polluted water.
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NANOTECHNOLOGY
·
2019
·Vol. 31
·期 6
·065603
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IF 3.399
Chun Sun,Le Wang,Sijing Su,Zhiyuan Gao,Hua Wu,Zi-hui Zhang,Wengang Bi
White light-emitting diodes (WLEDs) based on all-inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have attracted much attention and rely on mixing several colors of perovskites. However, this inevitably leads to a non-uniform light distribution and serious light loss. Here, a novel strategy was demonstrated to obtain white emission by combining the orange and blue emission from CsPb/Mn(Cl/Br)3 QDs. Notably, highly efficient white emission with a photoluminescence quantum yield of 94% was achieved by an anion exchange surface engineering (AESE) strategy. After AESE treatment the surface traps can be eliminated, resulting in improved exciton and Mn2+ emission. A prototype WLED device was fabricated and exhibited excellent optical stability, demonstrating great potential for perovskite QDs in the field of optoelectronics.
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