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Stress‐Transfer‐Induced In Situ Formation of Ultrathin Nickel Phosphide Nanosheets for Efficient Hydrogen Evolution 下载免费PDF全文
Shao‐Hai Li Dr. Nan Zhang Dr. Xiuqiang Xie Prof. Dr. Rafael Luque Prof. Dr. Yi‐Jun Xu 《Angewandte Chemie (International ed. in English)》2018,57(40):13082-13085
Ultrathin two‐dimensional (2D) nanostructures have attracted increasing research interest for energy storage and conversion. However, tackling the key problem of lattice mismatch inducing the instability of ulreathin nanostructures during phase transformations is still a critical challenge. Herein, we describe a facile and scalable strategy for the growth of ultrathin nickel phosphide (Ni2P) nanosheets (NSs) with exposed (001) facets. We show that single‐layer functionalized graphene with residual oxygen‐containing groups and a large lateral size contributes to reducing the lattice strain during phosphorization. The resulting nanostructure exhibits remarkable hydrogen evolution activity and good stability under alkaline conditions. 相似文献
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采用简便的一步水热合成法,在泡沫镍上原位生长微量W~(6+)掺入的Fe_(0.2)Ni(OH)_2双金属层状氢氧化物(LDH),以此来降低铁镍材料的过电势。通过场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和拉曼光谱(Raman)等分析方法对材料形貌、组成、结构等进行表征,发现钨掺杂使催化剂材料的晶体结构和电子结构发生变化,W_(0.03)Fe_(0.2)Ni(OH)_2LDH表现出优异的电化学析氧(OER)和析氢(HER)性能。电化学测试表明该催化剂在25 mA·cm~(-2)电流密度下OER和HER过电势分别仅有271和208 mV,塔菲尔斜率分别为61和181 mV·dec~(-1)。此外,经过长达20 h计时电位稳定性测试后,材料的催化性能未见明显下降。 相似文献
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Phosphorus‐Modified Tungsten Nitride/Reduced Graphene Oxide as a High‐Performance,Non‐Noble‐Metal Electrocatalyst for the Hydrogen Evolution Reaction 下载免费PDF全文
Dr. Haijing Yan Prof. Chungui Tian Dr. Lei Wang Dr. Aiping Wu Meichen Meng Lu Zhao Prof. Honggang Fu 《Angewandte Chemie (International ed. in English)》2015,54(21):6325-6329
Phosphorus‐modified tungsten nitride/reduced graphene oxide (P‐WN/rGO) is designed as a high‐efficient, low‐cost electrocatalyst for the hydrogen evolution reaction (HER). WN (ca. 3 nm in size) on rGO is first synthesized by using the H3[PO4(W3O9)4] cluster as a W source. Followed by phosphorization, the particle size increase slightly to about 4 nm with a P content of 2.52 at %. The interaction of P with rGO and WN results in an obvious increase of work function, being close to Pt metal. The P‐WN/rGO exhibits low onset overpotential of 46 mV, Tafel slope of 54 mV dec?1, and a large exchange current density of 0.35 mA cm?2 in acid media. It requires overpotential of only 85 mV at current density of 10 mA cm?2, while remaining good stability in accelerated durability testing. This work shows that the modification with a second anion is powerful way to design new catalysts for HER. 相似文献
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Real‐time Observation of Deep Lithiation of Tungsten Oxide Nanowires by In Situ Electron Microscopy 下载免费PDF全文
Kuo Qi Jiake Wei Muhua Sun Qianming Huang Xiaomin Li Zhi Xu Dr. Wenlong Wang Dr. Xuedong Bai 《Angewandte Chemie (International ed. in English)》2015,54(50):15222-15225
An in‐depth mechanistic understanding of the electrochemical lithiation process of tungsten oxide (WO3) is both of fundamental interest and relevant for potential applications. One of the most important features of WO3 lithiation is the formation of the chemically flexible, nonstoichiometric LixWO3, known as tungsten bronze. Herein, we achieved the real‐time observation of the deep electrochemical lithiation process of single‐crystal WO3 nanowires by constructing in situ transmission electron microscopy (TEM) electrochemical cells. As revealed by nanoscale imaging, diffraction, and spectroscopy, it is shown that the rapid and deep lithiation of WO3 nanowires leads to the formation of highly disordered and near‐amorphous LixWO3 phases, but with no detectable traces of elemental W and segregated Li2O phase formation. These results highlight the remarkable chemical and structural flexibility of the LixWO3 phases in accommodating the rapid and deep lithiation reaction. 相似文献
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Crystalline Covalent Triazine Frameworks by In Situ Oxidation of Alcohols to Aldehyde Monomers 下载免费PDF全文
Manying Liu Qi Huang Shaolei Wang Dr. Ziyong Li Dr. Buyi Li Prof. Shangbin Jin Prof. Bien Tan 《Angewandte Chemie (International ed. in English)》2018,57(37):11968-11972
Covalent triazine frameworks (CTFs) with aromatic triazine linkages have recently received increasing interest for various applications because of their rich nitrogen content and high chemical stability. Owing to the strong aromatic C=N bond and high chemical stability, only a few CTFs are crystalline, and most CTFs are amorphous. Herein we report a new general strategy to give highly crystalline CTFs by in situ formation of aldehyde monomers through the controlled oxidation of alcohols. This general strategy allows a series of crystalline CTFs with different monomers to be prepared, which are shown to have higher thermal stability and enhanced performance in photocatalysis as compared with the less crystalline or amorphous CTFs. This open‐system approach is very simple and convenient, which presents a potential pathway to large‐scale industrial production of crystalline CTFs. 相似文献
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Dr. Antonia Kagkoura Dr. Ruben Canton-Vitoria Dr. Lorenzo Vallan Dr. Javier Hernandez-Ferrer Dr. Ana M. Benito Dr. Wolfgang K. Maser Dr. Raul Arenal Dr. Nikos Tagmatarchis 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(29):6635-6642
The preparation of an MoS2–polymer carbon nanodot (MoS2-PCND) hybrid material was accomplished by employing an easy and fast bottom-up synthetic approach. Specifically, MoS2-PCND was realized by the thermal decomposition of ammonium tetrathiomolybdate and the in situ complexation of Mo with carboxylic acid units present on the surface of PCNDs. The newly prepared hybrid material was comprehensively characterized by spectroscopy, thermal means, and electron microscopy. The electrocatalytic activity of MoS2-PCND was examined in the hydrogen evolution reaction (HER) and compared with that of the corresponding hybrid material prepared by a top-down approach, namely MoS2-PCND(exf-fun), in which MoS2 was firstly exfoliated and then covalently functionalized with PCNDs. The MoS2-PCND hybrid material showed superior electrocatalytic activity toward the HER with low Tafel slope, excellent electrocatalytic stability, and an onset potential of −0.16 V versus RHE. The superior catalytic performance of MoS2-PCND was rationalized by considering the catalytically active sites of MoS2, the effective charge/energy-transfer phenomena from PCNDs to MoS2, and the synergetic effect between MoS2 and PCNDs in the hybrid material. 相似文献
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Large‐Area,Free‐Standing,Two‐Dimensional Supramolecular Polymer Single‐Layer Sheets for Highly Efficient Electrocatalytic Hydrogen Evolution 下载免费PDF全文
Dr. Renhao Dong Martin Pfeffermann Dr. Haiwei Liang Dr. Zhikun Zheng Dr. Xiang Zhu Dr. Jian Zhang Prof. Dr. Xinliang Feng 《Angewandte Chemie (International ed. in English)》2015,54(41):12058-12063
The rational construction of covalent or noncovalent organic two‐dimensional nanosheets is a fascinating target because of their promising applications in electronics, membrane technology, catalysis, sensing, and energy technologies. Herein, a large‐area (square millimeters) and free‐standing 2D supramolecular polymer (2DSP) single‐layer sheet (0.7–0.9 nm in thickness), comprising triphenylene‐fused nickel bis(dithiolene) complexes has been readily prepared by using the Langmuir–Blodgett method. Such 2DSPs exhibit excellent electrocatalytic activities for hydrogen generation from water with a Tafel slope of 80.5 mV decade?1 and an overpotential of 333 mV at 10 mA cm?2, which are superior to that of recently reported carbon nanotube supported molecular catalysts and heteroatom‐doped graphene catalysts. This work is promising for the development of novel free‐standing organic 2D materials for energy technologies. 相似文献
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Anodic Hydrazine Oxidation Assists Energy‐Efficient Hydrogen Evolution over a Bifunctional Cobalt Perselenide Nanosheet Electrode 下载免费PDF全文
Jun‐Ye Zhang Prof. Dr. Hongming Wang Yifan Tian Prof. Dr. Ya Yan Qi Xue Ting He Prof. Dr. Hongfang Liu Dr. Chundong Wang Prof. Dr. Yu Chen Prof. Dr. Bao Yu Xia 《Angewandte Chemie (International ed. in English)》2018,57(26):7649-7653
Water electrolysis is a promising source of hydrogen; however, technological challenges remain. Intensive efforts have focused on developing highly efficient and earth‐abundant electrocatalysts for water splitting. An effective strategy is proposed, using a bifunctional tubular cobalt perselenide nanosheet electrode, in which the sluggish oxygen evolution reaction is substituted with anodic hydrazine oxidation so as to assist energy‐efficient hydrogen production. Specifically, this electrode produces a current density of 10 mA cm?2 at ?84 mV for hydrogen evolution and ?17 mV for hydrazine oxidation in 1.0 m KOH and 0.5 m hydrazine electrolyte. An ultralow cell voltage of only 164 mV is required to generate a current density of 10 mA cm?2 for 14 hours of stable water electrolysis. 相似文献
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本文以石墨烯氧化物(GO)和硫代钼酸铵((NH4)2MoS4)为前体,曙红(EY)和三乙醇胺(TEOA)为光敏单元和电子牺牲体,通过一种环境友好的光还原方法原位制备了石墨烯-硫化钼(RGO-MoSx)产氢催化剂。RGO-MoSx表现出高效的催化产氢活性,石墨烯的引入使其催化产氢效率提高至原来的2.10倍。通过傅里叶红外光谱(FTIR)、拉曼光谱(Raman)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)表征,证实了RGO-MoSx的组成、结构及形貌特征。 相似文献
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An In Situ Depot for Continuous Evolution of Gaseous H2 Mediated by a Magnesium Passivation/Activation Cycle for Treating Osteoarthritis 下载免费PDF全文
Wei‐Lin Wan Dr. Yu‐Jung Lin Po‐Chien Shih Yu‐Ru Bow Dr. Qinghua Cui Dr. Yen Chang Dr. Wei‐Tso Chia Prof. Hsing‐Wen Sung 《Angewandte Chemie (International ed. in English)》2018,57(31):9875-9879
Inflammation is involved in many human pathologies, including osteoarthritis (OA). Hydrogen (H2) is known to have anti‐inflammatory effects; however, the bioavailability of directly administered H2 gas is typically poor. Herein, a local delivery system that can provide a high therapeutic concentration of gaseous H2 at inflamed tissues is proposed. The delivery system comprises poly(lactic‐co‐glycolic acid) microparticles that contain magnesium powder (Mg@PLGA MPs). Mg@PLGA MPs that are intra‐muscularly injected close to the OA knee in a mouse model can act as an in situ depot that can evolve gaseous H2 continuously, mediated by the cycle of passivation/activation of Mg in body fluids, at a concentration that exceeds its therapeutic threshold. The analytical data that are obtained in the biochemical and histological studies indicate that the proposed Mg@PLGA MPs can effectively mitigate tissue inflammation and prevent cartilage from destruction, arresting the progression of OA changes. 相似文献
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Dr. Qi Hu Guomin Li Zhen Han Ziyu Wang Xiaowan Huang Dr. Hengpan Yang Prof. Qianling Zhang Prof. Jianhong Liu Prof. Chuanxin He 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):3930-3942
Recently, nonmetal doping has exhibited its great potential for boosting the hydrogen evolution reaction (HER) of transition-metal (TM)-based electrocatalysts. To this end, this work overviews the recent achievements made on the design and development of the nonmetal-doped TM-based electrocatalysts and their performance for the HER. It is also shown that by rationally doping nonmetal elements, the electronic structures of TM-based electrocatalysts can be effectively tuned and in turn the Gibbs free energy of the TM for adsorption of H* intermediates (ΔGH*) optimized, consequently enhancing the intrinsic activity of TM-based electrocatalysts. Notably, we highlight that concurrently doping two nonmetal elements can continuously and precisely regulate the electronic structures of the TM, thereby maximizing the activity for HER. Moreover, nonmetal doping also accounts for enhancing the physical properties of the TM (i.e. surface area). Therefore, nonmetal doping is a robust strategy for simultaneous regulation of the chemical and physical features of the TM. 相似文献
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Lei Sun Jiahui Geng Dr. Mengyou Gao Dr. Dehua Zheng Zhongxin Jing Qingyun Zhao Prof. Jianjian Lin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(42):10998-11004
Fe0.95S1.05 with high reactivity and stability was incorporated into WS2 nanosheets via a one-step solvothermal method for the first time. The resulted hybrid catalyst has much higher catalytic activity than WS2 and Fe0.95S1.05 alone, and the optimal WS2/Fe0.95S1.05 hybrid catalyst was found by adjusting the feed ratio. The addition of Fe0.95S1.05 was proven to be able to enhance the hydrogen evolution reaction (HER) activity of WS2, and vice versa. At the same time, it was found that the catalytic effect of the hybrid catalyst was the best when the feed ratio was W : Fe=2 : 1. In other words, we confirmed that there is a synergistic effect between W- and Fe-based sulfide hybrid catalysts, and validated that the reason for the improved HER performance is the strong interaction between the two in the middle sulfur. WS2/Fe0.95S1.05-2 hybrid catalyst leads to enhanced HER activity, which shows a low overpotential of ∼0.172 V at 10 mA cm−2, low Tafel slope of ∼53.47 mV/decade. This study supplies innovative synthesis of a highly active WS2/Fe0.95S1.05 hybrid catalyst for HER. 相似文献
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Dr. Jaesung Yang Prof. Dr. Heungman Park Prof. Dr. Laura J. Kaufman 《Angewandte Chemie (International ed. in English)》2018,57(7):1826-1830
Understanding the mechanisms that contribute to conjugated polymer aggregate formation and growth may yield enhanced control of aggregate morphology and functional properties on the mesoscopic scale. In situ optical imaging of the growth of MEH‐PPV aggregates in real time in controlled swollen films shows that growth occurs through multiple mechanisms and is more complex than previously described. Direct evidence is provided for both Ostwald ripening and aggregate coalescence as operative modes of aggregate growth in solvent swollen films. These growth mechanisms have a distinct and strong impact on the evolution of morphological order of growing aggregates: while Ostwald ripening allows preservation of highly ordered morphology, aggregate coalescence occurs with no preferential orientation, leading to attenuation in degree of ordering. 相似文献
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In continuation of the work on establishing hydrogen donors in the hydrogen evolution reaction from different acid molecules, cathodic evolution of hydrogen on silver is investigated from solutions of monobasic acetic acid with the aim to establish the origin of reduced hydrogen. Solutions of 0.2 M acetic acid with 0.2 M perchloric acid, neutralized to different pH values by NaOH, are used. The earlier established criterion is used for discerning between two possible hydrogen evolution mechanisms: (1) from dissociated hydrogen ions and (2) from undissociated hydrogen atoms in the molecule. At medium pH values, the undissociated acid molecules participate as hydrogen donors. Rate constants for reactions 1 and 2, evaluated at a potential of –800 mV (SCE), at which the entire pH range can be scanned, are 2.9 × 10–6 and 1.9 × 10–8. 相似文献
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Yan Zhang Fei Ye Wei-Dong Z. Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(11):3766-3771
The development of high-efficiency bifunctional electrocatalysts toward the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline surroundings is essential and challenging for the large-scale generation of clean hydrogen. Herein, a novel self-assembled two-dimensional (2 D) NiO/CeO2 heterostructure (HS) consisting of NiO and CeO2 nanocrystals is prepared through a facile two-step approach, and utilized as an enhanced bifunctional electrocatalyst for the HER and OER under alkaline conditions. It is concluded that this 2 D NiO/CeO2 HS, rich in oxygen vacancies, demonstrates attractive electrocatalytic properties for both the HER and OER in 1 m KOH, including low onset overpotential (η1), η10 and Tafel slope, excellent durability, as well as large active surface area. Therefore, the self-assembled 2 D NiO/CeO2 HS is believed to be an efficient bifunctional electrocatalyst toward the HER and OER. 相似文献
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ZnO/ZnS Heterostructured Nanorod Arrays and Their Efficient Photocatalytic Hydrogen Evolution 下载免费PDF全文
Dr. Di Bao Prof. Peng Gao Dr. Xinyang Zhu Dr. Shuchao Sun Dr. Ying Wang Dr. Xiaobo Li Prof. Yujin Chen Dr. Han Zhou Dr. Yanbo Wang Prof. Piaoping Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12728-12734
Semiconducting heterostructures have been widely applied in photocatalytic hydrogen evolution due to their variable band gaps and high energy conversion efficiency. As typical semiconducting heterostructures, ZnO/ZnS heterostructured nanorod arrays (HNRAs) have been obtained through a simple anion‐exchange process in this work. Structural characterization indicates that the heterostructured nanorods (HNRs) are all composed of hexagonal wurtzite ZnO core and cubic zinc‐blende ZnS shell. As expected, the as‐obtained one‐dimensional heterostructures not only lower the energy barrier but also enhance the separation ability of photogenerated carriers in photocatalytic hydrogen evolution. Through comparisons, it is found that 1D ZnO/ZnS HNRAs exhibit much better performance in photocatalytic hydrogen evolution than 1D ZnO nanorod arrays (NRAs) and 1D ZnS NRAs. The maximum H2 production is 19.2 mmol h?1 for 0.05 g catalyst under solar‐simulated light irradiation at 25 °C and the corresponding quantum efficiency is 13.9 %, which goes beyond the economical threshold of photocatalytic hydrogen evolution technology. 相似文献