共查询到20条相似文献,搜索用时 15 毫秒
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Kang Xiao Yifan Wang Peiyuan Wu Liping Hou Prof. Zhao-Qing Liu 《Angewandte Chemie (International ed. in English)》2023,62(24):e202382461
The development of productive catalysts for the oxygen evolution reaction (OER) remains a major challenge requiring significant progress in both mechanism and material design. Conventionally, the thermodynamic barrier of lattice oxidation mechanism (LOM) is lower than that of absorbate evolution mechanism (AEM) because the former can overcome certain limitations. However, controlling the OER pathway from the AEM to the LOM by exploiting the intrinsic properties of the catalyst remains challenging. Herein, we incorporated F anions into the oxygen vacancies of spinel ZnCo2O4 and established a link between the electronic structure and the OER catalytic mechanism. Theoretical density calculations revealed that F upshifts the O 2p center and activates the redox capability of lattice O, successfully triggering the LOM pathway. Moreover, the high electronegativity of F anions is favourable for balancing the residual protonation, which can stabilize the structure of the catalyst. 相似文献
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Hongting Du Haoran Guo Kaike Wang Xiangning Du Bayu Admasu Beshiwork Shengjun Sun Yongsong Luo Dr. Qian Liu Prof. Tingshuai Li Prof. Xuping Sun 《Angewandte Chemie (International ed. in English)》2023,62(5):e202215782
We propose the pseudobrookite Fe2TiO5 nanofiber with abundant oxygen vacancies as a new electrocatalyst to ambiently reduce nitrate to ammonia. Such catalyst achieves a large NH3 yield of 0.73 mmol h−1 mg−1cat. and a high Faradaic Efficiency (FE) of 87.6 % in phosphate buffer saline solution with 0.1 M NaNO3, which is lifted to 1.36 mmol h−1 mg−1cat. and 96.06 % at −0.9 V vs. RHE for nitrite conversion to ammonia in 0.1 M NaNO2. It also shows excellent electrochemical durability and structural stability. Theoretical calculation reveals the enhanced conductivity of this catalyst and an extremely low free energy of −0.28 eV for nitrate adsorption at the presence of vacant oxygen. 相似文献
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Xiaofang Bai Xiuping Zhang Yujiao Sun Mingcheng Huang Prof. Dr. Jiantao Fan Prof. Dr. Shaoyi Xu Prof. Dr. Hui Li 《Angewandte Chemie (International ed. in English)》2023,62(38):e202308704
To date, only a few noble metal oxides exhibit the required efficiency and stability as oxygen evolution reaction (OER) catalysts under the acidic, high-voltage conditions that exist during proton exchange membrane water electrolysis (PEMWE). The high cost and scarcity of these catalysts hinder the large-scale application of PEMWE. Here, we report a novel OER electrocatalyst for OER comprised of uniformly dispersed Ru clusters confined on boron carbon nitride (BCN) support. Compared to RuO2, our BCN-supported catalyst shows enhanced charge transfer. It displays a low overpotential of 164 mV at a current density of 10 mA cm−2, suggesting its excellent OER catalytic activity. This catalyst was able to operate continuously for over 12 h under acidic conditions, whereas RuO2 without any support fails in 1 h. Density functional theory (DFT) calculations confirm that the interaction between the N on BCN support and Ru clusters changes the adsorption capacity and reduces the OER energy barrier, which increases the electrocatalytic activity of Ru. 相似文献
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Dr. Rhone P. Brocha Silalahi Yongsung Jo Dr. Jian-Hong Liao Tzu-Hao Chiu Eunsaem Park Dr. Woojun Choi Hao Liang Dr. Samia Kahlal Prof. Dr. Jean-Yves Saillard Prof. Dr. Dongil Lee Prof. Dr. C. W. Liu 《Angewandte Chemie (International ed. in English)》2023,62(16):e202301272
The first hydride-containing 2-electron palladium/copper alloys, [PdHCu11{S2P(OiPr)2}6(C≡CPh)4] ( PdHCu11 ) and [PdHCu12{S2P(OiPr)2}5{S2PO(OiPr)} (C≡CPh)4] ( PdHCu12 ), are synthesized from the reaction of [PdH2Cu14{S2P(OiPr)2}6(C≡CPh)6] ( PdH2Cu14 ) with trifluoroacetic acid (TFA). X-ray diffraction reveals that the PdHCu11 and PdHCu12 kernels consist of a central PdH unit encapsulated within a vertex-missing Cu11 cuboctahedron and complete Cu12 cuboctahedron, respectively. DFT calculations indicate that both PdHCu11 and PdHCu12 can be considered as axially-distorted 2-electron superatoms. PdHCu11 shows excellent HER activity, unprecedented within metal nanoclusters, with an onset potential of −0.05 V (at 10 mA cm−2), a Tafel slope of 40 mV dec−1, and consistent HER activity during 1000 cycles in 0.5 M H2SO4. Our study suggests that the accessible central Pd site is the key to HER activity and may provide guidelines for correlating catalyst structures and HER activity. 相似文献
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Pt/TiO2纳米纤维的制备及其对甲醇的电催化氧化活性 总被引:1,自引:0,他引:1
采用静电纺丝技术结合还原浸渍法制备了Pt/TiO2纳米纤维电催化剂, 通过X射线衍射(XRD)分析、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDS)等测试手段对样品的晶相、形貌、微结构和化学组成进行了表征. 测试结果表明, TiO2纳米纤维为锐钛矿和金红石组成的混晶, Pt 纳米颗粒均匀地分布于TiO2纳米纤维的表面, 且Pt 颗粒大小较均一, 平均粒径为4.0 nm, Pt/TiO2纳米纤维中Pt 的质量分数约为20%. 采用三电极体系的循环伏安和计时电流电化学分析方法研究了样品在酸性溶液中对甲醇的电催化氧化活性, 结果表明, 与负载相同质量分数Pt 的Pt/P25 和商业Pt/C 催化剂相比较, Pt/TiO2纳米纤维催化剂对甲醇呈现出较高的电催化氧化活性和更好的稳定性. 相似文献
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Luqi Wang Zipeng Xu Chun-Han Kuo Jian Peng Prof. Feng Hu Prof. Linlin Li Prof. Han-Yi Chen Prof. Jiazhao Wang Prof. Shengjie Peng 《Angewandte Chemie (International ed. in English)》2023,62(42):e202311937
Designing novel single-atom catalysts (SACs) supports to modulate the electronic structure is crucial to optimize the catalytic activity, but rather challenging. Herein, a general strategy is proposed to utilize the metalloid properties of supports to trap and stabilize single-atoms with low-valence states. A series of single-atoms supported on the surface of tungsten carbide (M-WCx, M=Ru, Ir, Pd) are rationally developed through a facile pyrolysis method. Benefiting from the metalloid properties of WCx, the single-atoms exhibit weak coordination with surface W and C atoms, resulting in the formation of low-valence active centers similar to metals. The unique metal-metal interaction effectively stabilizes the low-valence single atoms on the WCx surface and improves the electronic orbital energy level distribution of the active sites. As expected, the representative Ru-WCx exhibits superior mass activities of 7.84 and 62.52 A mgRu−1 for the hydrogen oxidation and evolution reactions (HOR/HER), respectively. In-depth mechanistic analysis demonstrates that an ideal dual-sites cooperative mechanism achieves a suitable adsorption balance of Had and OHad, resulting in an energetically favorable Volmer step. This work offers new guidance for the precise construction of highly active SACs. 相似文献
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Boyan Liu Xin Wang Yingjuan Zhang Liangcheng Xu Tingsheng Wang Xiong Xiao Prof. Songcan Wang Prof. Lianzhou Wang Prof. Wei Huang 《Angewandte Chemie (International ed. in English)》2023,62(10):e202217346
Sluggish oxygen evolution kinetics are one of the key limitations of bismuth vanadate (BiVO4) photoanodes for efficient photoelectrochemical (PEC) water splitting. To address this issue, we report a vanadium oxide (VOx) with enriched oxygen vacancies conformally grown on BiVO4 photoanodes by a simple photo-assisted electrodeposition process. The optimized BiVO4/VOx photoanode exhibits a photocurrent density of 6.29 mA cm−2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, which is ca. 385 % as high as that of its pristine counterpart. A high charge-transfer efficiency of 96 % is achieved and stable PEC water splitting is realized, with a photocurrent retention rate of 88.3 % upon 40 h of testing. The excellent PEC performance is attributed to the presence of oxygen vacancies in VOx that forms undercoordinated sites, which strengthen the adsorption of water molecules onto the active sites and promote charge transfer during the oxygen evolution reaction. This work demonstrates the potential of vanadium-based catalysts for PEC water oxidation. 相似文献
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利用对氧缺陷的TiO2-B材料进行密度泛函理论的计算,阐述了氧空穴对于TiO2-B材料的电化学性质的影响。计算研究主要聚焦于缺陷材料的锂离子迁移和电子导电性等基本问题。计算结果表明在低锂离子浓度下(x(Li/Ti)≤ 0.25),相比于无缺陷的TiO2-B,氧缺陷TiO2-B有着更高的插入电压和更低的b轴方向迁移活化能,意味着锂离子的嵌入也更容易,这对于可充电电池的充电过程是有利的。而在高浓度下(x(Li/Ti) = 1),锂饱和的氧缺陷TiO2-B相较于无缺陷的TiO2-B有着较低的插入电压,更有利于锂离子的脱嵌过程,这对于可充电电池的放电过程也是有利的。电子结构计算表明缺陷材料的禁带宽度在1.0-2.0 eV之间,低于无缺陷的材料的3.0 eV。主要态密度贡献者是Ti-Ov-3d,并且随着氧空穴的增加它的强度也变得更强。这就表明氧缺陷TiO2-B有更好的电子导电性。 相似文献
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几种低碳醇在Pt/TiO2上的光催化产氢速率的研究 总被引:4,自引:1,他引:4
主要考察了无氧条件下低碳醇(甲、乙、丙醇)在Pt/TiO2表面光催化重整反应制氢。深入探讨了几种低碳醇与其放氢速率的构-效关系,提出了低碳醇在Pt/TiO2光催化剂表面吸附态的模型。 相似文献
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Yang Yang Lijia Liu Shuai Chen Wenjun Yan Haiqing Zhou Xian-Ming Zhang Xiujun Fan 《Angewandte Chemie (International ed. in English)》2023,62(46):e202306896
Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8O26-NbNxOy supported on N-doped graphene (defined as Mo8O26-NbNxOy/NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O-exposed Mo8O26 clusters covalently confined on NbNxOy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH-universal electrolytes. Theoretical studies reveal that the Mo8O26-NbNxOy interface with electronic reconstruction affords near-optimal hydrogen adsorption energy and enhanced initial H2O adsorption. Furthermore, the terminal O atoms in Mo8O26 clusters cooperate with Nb atoms to promote the initial H2O adsorption, and subsequently reduce the H2O dissociation energy, accelerating the entire HER kinetics. 相似文献
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Hai-Jun Liu Shuo Zhang Prof. Yong-Ming Chai Prof. Bin Dong 《Angewandte Chemie (International ed. in English)》2023,62(48):e202313845
Highly efficient hydrogen evolution reaction (HER) electrocatalyst will determine the mass distributions of hydrogen-powered clean technologies, while still faces grand challenges. In this work, a synergistic ligand modulation plus Co doping strategy is applied to 1T−MoS2 catalyst via CoMo-metal-organic frameworks precursors, boosting the HER catalytic activity and durability of 1T−MoS2. Confirmed by Cs corrected transmission electron microscope and X-ray absorption spectroscopy, the polydentate 1,2-bis(4-pyridyl)ethane ligand can stably link with two-dimensional 1T−MoS2 layers through cobalt sites to expand interlayer spacing of MoS2 (Co−1T−MoS2-bpe), which promotes active site exposure, accelerates water dissociation, and optimizes the adsorption and desorption of H in alkaline HER processes. Theoretical calculations indicate the promotions in the electronic structure of 1T−MoS2 originate in the formation of three-dimensional metal-organic constructs by linking π-conjugated ligand, which weakens the hybridization between Mo-3d and S-2p orbitals, and in turn makes S-2p orbital more suitable for hybridization with H-1s orbital. Therefore, Co−1T−MoS2-bpe exhibits excellent stability and exceedingly low overpotential for alkaline HER (118 mV at 10 mA cm−2). In addition, integrated into an anion-exchange membrane water electrolyzer, Co−1T−MoS2-bpe is much superior to the Pt/C catalyst at the large current densities. This study provides a feasible ligand modulation strategy for designs of two-dimensional catalysts. 相似文献
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Xueping Yu Chan Yang Shan Zhang Yonglei Xing Chuntai Liu Juan Peng Qingyu Yan 《化学:亚洲杂志》2020,15(18):2892-2899
A novel MoS2 quantum dots/CoSe2 nanosheet (MoS2 QDs/CoSe2) hybrid with 0D/2D heterostructure has been developed. The CoSe2 nanosheets (NSs) enable an excellent oxygen evolution reaction (OER) activity with increasing vacancy configuration on one hand, while the MoS2 QDs serve as an eminent hydrogen evolution reaction (HER) catalyst on the other. By integrating MoS2 QDs and CoSe2 NSs, the hybrid exhibits excellent electrocatalytic performances in HER and OER. The unique 0D/2D hetero‐interface increases the exposed active sites and facilitates electron transfer, thereby boosting the electrocatalytic activity. Relatively low overpotentials of 82 mV and 280 mV are required to drive the current density of 10 mA/cm2 for HER and OER, with corresponding Tafel slopes of 69 and 75 mV/dec, respectively. As such, this work provides an efficient yet simple approach to construct bifunctional electrocatalysts with enhanced activity and stability. 相似文献
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采用溶剂热法制备了多种二维过渡金属硫化物(TMDCs), 在合成过程中通过调控反应前驱体的滴加速率来控制所得TMDCs的形貌和结构. 然后采用高温热处理来提高TMDCs的结晶性, 从而提升了其电催化活性. 在酸性电解液中进行电催化析氢性能测试. 结果表明, “花状”结构的金属性二维二硫化铌(NbS2)具有最佳的催化活性和稳定性, 在电流密度为10 mA/cm2时, 其过电位仅为146 mV, 持续工作24 h后电流密度几乎不衰减. 研究发现, 可充分暴露面内活性位点的“花状”结构以及高温处理后材料导电性的提高是二维NbS2具有优异电催化性能的主要因素. 相似文献
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Zisheng Zhang Dr. Tsugunosuke Masubuchi Prof. Philippe Sautet Prof. Scott L. Anderson Prof. Anastassia N. Alexandrova 《Angewandte Chemie (International ed. in English)》2023,62(20):e202218210
We report the size-dependent activity and stability of supported Pt1,4,7,8 for electrocatalytic hydrogen evolution reaction, and show that clusters outperform polycrystalline Pt in activity, with size-dependent stability. To understand the size effects, we use DFT calculations to study the structural fluxionality under varying potentials. We show that the clusters can reshape under H coverage and populate an ensemble of states with diverse stoichiometry, structure, and thus reactivity. Both experiment and theory suggest that electrocatalytic species are hydridic states of the clusters (≈2 H/Pt). An ensemble-based kinetic model reproduces the experimental activity trend and reveals the role of metastable states. The stability trend is rationalized by chemical bonding analysis. Our joint study demonstrates the potential- and adsorbate-coverage-dependent fluxionality of subnano clusters of different sizes and offers a systematic modeling strategy to tackle the complexities. 相似文献
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Based on previous works, most of the transition metal phosphides (TMPs) were directly prepared by decomposing NaH2PO2 with the precursors at high temperatures, which resulted in different degrees of phosphidation in the final product. Therefore, it is necessary to design an innovative approach to enhance the degree of phosphidation in the material using crystal defects. Here, oxygen-vacancy iron oxide/iron foam (Ov-Fe2O3/IF) was firstly prepared by generating oxygen vacancy in situ in an iron foam through heating in vacuum conditions. Subsequently, FeP/IF was formed by phosphating Ov-Fe2O3/IF. Under the effects of oxygen vacancies, oxygen-vacancy iron oxide could be completely phosphatized to produce more active sites on the surface of the material. This, in turn, could result in a catalyst with exceptional hydrogen evolution activity. Thus, the successful fabrication of FeP/IF demonstrated in this work provides an effective and feasible way for the preparation of other high-efficiency catalysts. 相似文献
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以Pt/TiO2为催化剂, 研究了以葡萄糖和蔗糖为电子给体的光催化制氢反应以及有机物自身的去除效果. 相似文献