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Dr. Cheng Tang Dr. Yan Jiao Prof. Bingyang Shi Jia-Ning Liu Dr. Zhenhua Xie Dr. Xiao Chen Prof. Qiang Zhang Prof. Shi-Zhang Qiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9256-9261
Single-atom catalysts (SACs) have great potential in electrocatalysis. Their performance can be rationally optimized by tailoring the metal atoms, adjacent coordinative dopants, and metal loading. However, doing so is still a great challenge because of the limited synthesis approach and insufficient understanding of the structure–property relationships. Herein, we report a new kind of Mo SAC with a unique O,S coordination and a high metal loading over 10 wt %. The isolation and local environment was identified by high-angle annular dark-field scanning transmission electron microscopy and extended X-ray absorption fine structure. The SACs catalyze the oxygen reduction reaction (ORR) via a 2 e− pathway with a high H2O2 selectivity of over 95 % in 0.10 m KOH. The critical role of the Mo single atoms and the coordination structure was revealed by both electrochemical tests and theoretical calculations. 相似文献
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Dr. Zhengping Zhang Dr. Junting Sun Prof. Feng Wang Prof. Liming Dai 《Angewandte Chemie (International ed. in English)》2018,57(29):9038-9043
Single Fe atoms dispersed on hierarchically structured porous carbon (SA‐Fe‐HPC) frameworks are prepared by pyrolysis of unsubstituted phthalocyanine/iron phthalocyanine complexes confined within micropores of the porous carbon support. The single‐atom Fe catalysts have a well‐defined atomic dispersion of Fe atoms coordinated by N ligands on the 3D hierarchically porous carbon support. These SA‐Fe‐HPC catalysts are comparable to the commercial Pt/C electrode even in acidic electrolytes for oxygen reduction reaction (ORR) in terms of the ORR activity (E1/2=0.81 V), but have better long‐term electrochemical stability (7 mV negative shift after 3000 potential cycles) and fuel selectivity. In alkaline media, the SA‐Fe‐HPC catalysts outperform the commercial Pt/C electrode in ORR activity (E1/2=0.89 V), fuel selectivity, and long‐term stability (1 mV negative shift after 3000 potential cycles). Thus, these nSA‐Fe‐HPCs are promising non‐platinum‐group metal ORR catalysts for fuel‐cell technologies. 相似文献
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Pengcheng Shen Jice Li Zhizhao Zhang Hui Liu LiMin Liang Cong Chen Ying Li 《International journal of quantum chemistry》2024,124(8):e27374
Driven by the goal of establishing a fossil-fuel-free and nuclear-power-free economy based on renewable energy, metal-air batteries are regarded as promising energy conversion and storage devices. Developing efficient oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional electrocatalysts for the air electrode of metal-air batteries is becoming increasingly important. In this work, 36 transition metal (TM) single-atom catalysts are designed based on MXenes Ti2CT2 with different surface terminal atoms (T = O, S, Cl), and their ORR/OER catalytic activity and stability are evaluated by the density functional theory. Ni@Ti2CO2, Pd@Ti2CS2, and Co@Ti2CCl2 are found to exhibit good catalytic activity with ORR/OER overpotentials of .54 V/.62 V, .59 V/.29 V, .44 V/.40 V. The aggregation behavior of three catalysts is estimated by comparing the average binding energy of one, two, three, and four TM atoms anchored on Ti2CT2. This work cannot only provide a theoretical guide to develop bifunctional single-atom catalysts, but also help us understand the effect of terminal atoms on the electronic structures and catalytic activity of TM@Ti2CT2. 相似文献
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Mn-N-C催化剂的制备及其在碱性介质中对氧还原反应的电催化性能 《燃料化学学报》2014,42(4):467-475
选用壳聚糖(CS)为原料制备了壳聚糖水杨醛席夫碱锰配合物(Mn-CS-sal)。将Mn-CS-sal配合物负载于石墨碳上得到碳载配合物(Mn-CS-sal/C),后经高温热处理得到Mn-N-C目标催化剂(Mn-N-C-t,t=200、400、600、800、1 000℃)。采用FT-IR、XRD、XPS和电化学等方法对催化剂的组成和结构进行了表征,对其在氧还原反应中的电催化性能进行了研究。结果表明,所得到的Mn-N-C催化剂对氧还原反应(ORR)具有很好的催化作用,但以600℃热处理制备的催化剂其活性最好。催化剂中Mn-N-C结构是催化ORR的活性位。采用循环伏安法获得了Mn-N-C-t催化ORR的动力学参数,即总的转移电子数n和电子传递系数αnα;具有最佳活性的Mn-N-C-600催化剂的总转移电子数为3.63,说明在此条件下,Mn-N-C-600催化ORR主要以4e转移途径为主,由此提出了可能的氧还原反应的机理。 相似文献
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Tobias Lffler Alan Savan Hajo Meyer Michael Meischein Valerie Strotktter Alfred Ludwig Wolfgang Schuhmann 《Angewandte Chemie (International ed. in English)》2020,59(14):5844-5850
Complex solid‐solution electrocatalysts (also referred to as high‐entropy alloy) are gaining increasing interest owing to their promising properties which were only recently discovered. With the capability of forming complex single‐phase solid solutions from five or more constituents, they offer unique capabilities of fine‐tuning adsorption energies. However, the elemental complexity within the crystal structure and its effect on electrocatalytic properties is poorly understood. We discuss how addition or replacement of elements affect the adsorption energy distribution pattern and how this impacts the shape and activity of catalytic response curves. We highlight the implications of these conceptual findings on improved screening of new catalyst configurations and illustrate this strategy based on the discovery and experimental evaluation of several highly active complex solid solution nanoparticle catalysts for the oxygen reduction reaction in alkaline media. 相似文献
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Guangqi Zhu Yanling Qi Fan Liu Shenqian Ma Prof. Guolei Xiang Dr. Fengmin Jin Dr. Zigeng Liu Prof. Wei Wang 《ChemSusChem》2021,14(3):866-875
The ordinary intrinsic activity and disordered distribution of metal sites in zero/one-dimensional (0D/1D) single-atom catalysts (SACs) lead to inferior catalytic efficiency and short-term endurance in the oxygen reduction reaction (ORR), which restricts the large-scale application of hydrogen−oxygen fuel cells and metal−air batteries. To improve the activity of SACs, a mild synthesis method was chosen to conjugate 1D Fe SACs with 2D graphene film (Fe SAC@G) that realized a composite structure with well-ordered atomic-Fe coordination configuration. The product exhibits outstanding ORR electrocatalytic efficiency and stability in 0.1 M KOH aqueous solution. DFT-D computational results manifest the intrinsic ORR activity of Fe SAC@G originated from the newly-formed FeN4−O−FeN4 bridge structure with moderate adsorption ability towards ORR intermediates. These findings provide new ways for designing SACs with high activity and long-term stability. 相似文献
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《应用化学》2010,27(02):183-190
A composite electrocatalyst cobalt-phthalocyanine loaded on carbon black VulcanXC-72(CoPc/C)was synthesized in one-step reaction through calcination, which could be used as the catalyst of air electrode. The product was characterized by XRD and IR techniques and shown to be CoPc/C composite with an average particle size of 30 nm. Its activity for oxygen reduction reaction(ORR) was evaluated by polarization curve and impedance spectrum in 6 mol/L KOH solution. With VulcanXC-72 pretreated in HNO3 as the carbon support, the CoPc/C calcinated at 600 ℃ exhibited the best catalytic activity. The polarization plots recorded at the electrode catalyzed with this product displyed an onset for ORR at -0.03 V（Hg/HgO）. The current density is 90×10-3 A/cm2 at -0.2 V in air. 相似文献
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碳载钴酞菁催化剂的一步法制备及其在碱性条件下对氧的电催化还原 总被引：1，自引：1，他引：0
通过固相加热,一步合成了以VulcanXC-72(碳黑)为载体的碳载钴酞菁(CoPc/C)复合催化剂,其可用作空气电极的氧还原催化剂。通过X射线衍射、红外光谱等测试技术对催化剂进行了表征。利用极化曲线和交流阻抗(EIS)方法测试了其在碱性介质(6mol/LKOH)中对氧还原的催化性能。结果显示,得到的产物为CoPc/C复合物,平均粒径30nm。以磷酸处理的碳黑为载体,在600℃下制备的CoPc/C复合催化剂表现出最佳的催化活性。以其制备的电极在空气气氛下-0.03V(Hg/HgO)电位时即可产生明显氧还原电流,-0.2V时电流密度达90×10-3A/cm2。 相似文献
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Dr. Kai S. Exner 《ChemElectroChem》2020,7(7):1528-1530
Dimensionally stable anodes (DSAs) have been established as anode material in the industrially important chlor-alkali process, owing to their long-term stability, high activity, and reasonable chlorine selectivity under operation conditions. Now, a new material, based on the idea of single-atom catalysis, has been reported, which reveals higher activity and chlorine selectivity than DSAs. 相似文献
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Since dual-metal single-atom catalyst (CoZnN/C) has been experimentally synthesized by atomically arching CoZn on N-doped carbon nanofibers and exhibited potential electrocatalysis activity towards oxygen reduction reaction (ORR), we perform first-principles calculations to identify the highly active sites at different defects by comparing the four-step ORR processes on the constructed four CoZnN6 models on graphene. The corresponding N-edge effect, dopant effect, and C-edge ring-closing effect are evaluated with the ORR evolution on different bonding environments, including pristine CoZnN6(OH), nanoribbon (NR) along zigzag direction, substitution of carbon/oxygen (C/O substitution), and C-edge ring-closing configurations. OH-ligand is shown to significantly improve the ORR activities for all the considered structures. Especially, C-substituted CoZnN6(OH), NR-CoZnN5O(OH) and CoZnN6(OH) with C-edge-effect exhibit obviously reduced overpotentials (ηlim=0.28, 0.48 and 0.41 V) of rate-determining steps among all the considered nine candidates. By plotting the relationship between the limiting potentials (Ulim) and free energies of intermediate *OH (ΔGOH*), two prior catalysts of pristine-CoZnN5C(OH) and defect-CoZnN6CH(OH) are located near the top of the volcano curve with higher Ulim=0.95 and 0.82 V than Pt(111) (Ulim=0.80 V), implying that C-substitution could facilitate ORR performance in pristine- and defect-CoZnN6(OH) bonding situation. 相似文献
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氧电极催化剂及缓慢的阴极氧还原动力学是制约低温燃料电池商业化的关键瓶颈因素之一。为此,国内外研究者近年来从提高低温燃料电池氧电极催化剂的催化活性和稳定性、降低催化剂的成本、发展非贵金属氧还原催化剂等方面开展了大量的研究工作,有力地促进了低温燃料电池的发展进程。本文在简要介绍低温燃料电池氧电极反应机理的基础上,从催化剂载体、贵金属及其合金催化剂、金属大环化合物及M-N/C类催化剂和过渡金属硫族化合物类催化剂等方面详细综述了低温燃料电池氧电极催化剂近年来的主要研究进展,并指出了各类催化剂目前尚待解决的问题和发展方向。 相似文献
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以氧化石墨烯(GO)为碳载体, K3Fe(CN)6同时作为N源和Fe源, 经热处理后构建了新型Fe/N/C结构的氧气还原催化剂. 在热处理过程中, 氧化石墨烯上的官能团分解脱离形成活性中心, Fe元素和N元素的同时掺杂是通过氧化石墨烯与K3Fe(CN)6之间的相互作用而实现的. 通过傅立叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)表征证明了这种非贵金属催化剂中N元素和Fe元素的成功掺杂, 在催化剂中N元素主要是以吡啶式氮、吡咯式氮和石墨式氮的形式存在, Fe(Ⅱ)和Fe(Ⅲ)则与其中的吡啶式氮配位形成Fe-Nx结构. 采用循环伏安法(CV)和旋转圆盘电极(RDE)技术, 研究其在碱性介质中对氧气还原反应(ORR)的电催化性能. 实验结果显示: Fe/N/C催化剂具有良好的ORR电催化活性, 在碱性溶液中的起始电位为-0.15 V, 同时有着良好的稳定性和抗甲醇性能. 相似文献
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Tianyu Zhang Xu Han Hongbin Yang Aijuan Han Enyuan Hu Yaping Li Xiao‐qing Yang Lei Wang Junfeng Liu Bin Liu 《Angewandte Chemie (International ed. in English)》2020,59(29):12055-12061
Single‐atom catalysts (SACs) show great promise for electrochemical CO2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the single‐atom electrode greatly limit their performance. Herein, we prepared a nickel single‐atom electrode consisting of isolated, high‐density and low‐valent nickel(I) sites anchored on a self‐standing N‐doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon‐fiber paper. The combination of single‐atom nickel(I) sites and self‐standing array structure gives rise to an excellent electrocatalytic CO2 reduction performance. The introduction of copper tunes the d‐band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single‐nickel‐atom electrode exhibits a specific current density of ?32.87 mA cm?2 and turnover frequency of 1962 h?1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency. 相似文献
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Tianyu Zhang Xu Han Hongbin Yang Prof. Aijuan Han Enyuan Hu Prof. Yaping Li Prof. Xiao-qing Yang Prof. Lei Wang Prof. Junfeng Liu Prof. Bin Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):12153-12159
Single-atom catalysts (SACs) show great promise for electrochemical CO2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the single-atom electrode greatly limit their performance. Herein, we prepared a nickel single-atom electrode consisting of isolated, high-density and low-valent nickel(I) sites anchored on a self-standing N-doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon-fiber paper. The combination of single-atom nickel(I) sites and self-standing array structure gives rise to an excellent electrocatalytic CO2 reduction performance. The introduction of copper tunes the d-band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single-nickel-atom electrode exhibits a specific current density of −32.87 mA cm−2 and turnover frequency of 1962 h−1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency. 相似文献
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Yuchen Xiao Anh N. Hong Dandan Hu Yanxiang Wang Prof. Xianhui Bu Prof. Pingyun Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16358-16365
Zeolitic imidazolate frameworks (ZIFs) are traditionally synthesized solvothermally by using cost- and waste-incurring organic solvents. Here, a direct synthesis method is reported for ZIF-8, ZIF-67, and their heterometallic versions from solid precursors only. This solvent-free crystallization method not only completely avoids organic solvents, but also provides an effective path for the synthesis of homogeneous mixed-metal ZIFs. Furthermore, under templating by NaCl/ZnCl2 eutectic salt, carbonization of the ZIF materials gives rise to a series of N-containing high-surface-area carbon materials with impressive catalytic properties for the oxygen reduction reaction. 相似文献
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Silver Juvanen Dr. Ave Sarapuu Dr. Sergei Vlassov Mati Kook Dr. Vambola Kisand Dr. Maike Käärik Dr. Alexey Treshchalov Jaan Aruväli Dr. Jekaterina Kozlova Dr. Aile Tamm Dr. Jaan Leis Dr. Kaido Tammeveski 《ChemElectroChem》2021,8(12):2288-2297
Iron-containing nitrogen-doped carbon catalysts for the electrochemical oxygen reduction reaction (ORR) were prepared by high-temperature pyrolysis of glucose, K3[Fe(CN)6], and dicyandiamide or urea as precursors. Sodium chloride was used as a template and a confining agent during the pyrolysis, while graphitic carbon nitride formed from dicyandiamide decomposed at higher temperatures, contributing to the enhancement of the porosity and nitrogen doping. The ratio of the precursors and the template was varied to improve the catalysts′ ORR activity, determined in alkaline solution by the rotating disk electrode method. The ORR inhibition tests by cyanide anions revealed the existence of nitrogen-coordinated Fe centres as electrocatalytically active sites in the doped catalyst. The high durability and methanol tolerance of the catalyst material prepared with an optimised precursor ratio make it a promising catalyst for applications in alkaline membrane fuel cells. 相似文献