共查询到20条相似文献,搜索用时 15 毫秒
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B.B. Damaskin 《Journal of Electroanalytical Chemistry》1975,65(2):799-814
It is shown that the weak specific adsorption of ions not involving the recharging of the electrode surface is characterized by the following unusual features: practical absence of any shift of p.z.c.; a very small discrepancy between the experimental differential capacity curves and similar curves calculated under the assumption that specific adsorption is absent (q1 = 0); insensitivity of the total surface excess of cations to their distribution between the dense and diffuse layers; practical independence of q1 of temperature and the bulk concentration of binary electrolyte; practical coincidence of c.t.p. calculated for different concentrations of surface-active supporting electrolyte assuming q1 = 0. It is also shown on the basis of the experimental data for the system {mc CsCl + (1 ? m)c LiCl} that the main fraction of the effective charge, determined by the mixed electrolyte method of Hurwitz—Parsons, results from the true specific adsorption of Cs+ cations at the Hg/H2O interface and only a small fraction of this charge (?20%) can be associated with different positions of the o.H.p. for Li+ and Cs+ ions. 相似文献
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The interaction of halide ions with the three noble metals has been investigated using the B3LYP density functional method and the cluster model approximation. The results of calculations for the M—X− and M12—X− (M = Cu, Ag, Au; X = F, Cl, Br, I) systems are presented. At the (100) surface, modeled in the present work by the M12 cluster, all halide ions have been found to adsorb preferentially at the hollow site, followed by the bridge and by the top positions. The adsorption energy has been found to decrease when going from fluoride to iodide in both atom—ion and cluster—ion cases. The opposite trend is observed for the estimates of the charge transfer from the ions to the surface. When different metals are compared, the M12—X− interaction energies decrease in the order Au > Ag > Cu, but for the smaller ions some deviations from this line do appear. The relative values of the calculated harmonic vibrational frequencies do agree with those found experimentally, but their magnitude is much smaller as a result of the effect of the lower surface coverage. 相似文献
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Dunfeng Gao Fan Cai Guoxiong Wang Xinhe Bao 《Current Opinion in Green and Sustainable Chemistry》2017
Electrochemical reduction of CO2 provides a sustainable solution to address the intermittent renewable electricity storage while recycling CO2 to produce fuels and chemicals. Highly efficient catalytic materials and reaction systems are required to drive this process economically. This Review highlights the new trends in advancing the electrochemical reduction of CO2 by developing and designing nanostructured heterogeneous catalysts. The activity, selectivity and reaction mechanism are significantly affected by the nano effects in nanostructured heterogeneous catalysts. In the future, energy efficiency and current density in electrochemical reduction of CO2 need to be further improved to meet the requirements for practical applications. 相似文献
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《中国化学快报》2023,34(6):107757
The electrochemical CO2 reduction reaction (CO2ER) is an emerging process that involves utilizing CO2 to produce valuable chemicals and fuels by consuming excess electricity from renewable sources. Recently, Cu and Cu-based nanoparticles, as earth-abundant and economical metal sources, have been attracting significant interest. The chemical and physical properties of Cu-based nanoparticles are modified by different strategies, and CO2 can be converted into multicarbon products. Among various Cu-based nanoparticles, Cu-based metal-organic frameworks (MOFs) are gaining increasing interest in the field of catalysis because of their textural, topological, and electrocatalytic properties. In this minireview, we summarized and highlighted the main achievements in the research on Cu-based MOFs and their advantages in the CO2ER as electrocatalysts, supports, or precursors. 相似文献
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Horányi G 《Journal of colloid and interface science》2003,261(2):580-583
The specific adsorption of radiolabeled sulfate ions from perchlorate supporting electrolyte onto TiO2 powder (anatase) has been investigated. The pH and concentration dependence of the adsorption was determined. Langmuir-like adsorption behavior similar to that on other oxides was found. From the pH dependence it follows that the protonation of the surface should precede the specific anion adsorption. The results obtained are compared with those reported for TiO2 bulk electrodes. 相似文献
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《中国化学快报》2023,34(7):108013
Copper is one of the most efficient catalysts widely investigated in electrochemical CO2 reduction, however, the further development of copper-based catalysts is constrained by severe stability problems. In this work, we developed a method for the synthesis of highly ordered CuAu intermetallic nanoalloys (o-CuAu) under mild conditions (< 250 °C), which can convert carbon dioxide to carbon monoxide with high selectivity and can operate stably for 160 h without current decay. The improved stability is believed to be due to the increased mixing enthalpy and stronger atomic interactions between Cu and Au atoms in the intermetallic nanoalloy. In addition, XPS results, Tafel slope and in situ IR spectroscopy demonstrate that high valence gold atoms on o-CuAu surface promote the reduction of CO2. In contrast, the disordered CuAu nanoalloy (d-CuAu) underwent atomic rearrangement to form a Cu-rich structure on the surface, leading to reduced stability. These findings may provide insight into the rational design of stable CO2RR electrocatalysts through proper structural engineering. 相似文献
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A.R. Despić 《Journal of Electroanalytical Chemistry》1985,184(2):401-404
The UPD of silver on platinum was studied as a function of the initial oxidation state of the surface. Twin-electrode thin-layer and semi-infinite voltammetric measurements show a strong interaction between silver and oxygenated species. The suerimposed processes are described in terms of the mixed electrosorption valency. However, the irreversibility of both processes restricts exact thermodynamic analysis. 相似文献
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Mengyang Fan Sébastien Garbarino Ana C. Tavares Daniel Guay 《Current Opinion in Electrochemistry》2020
Electrochemical reduction of CO2 (ERC) is a promising way to deal with CO2 emissions in the atmosphere, recycle CO2, and achieve a carbon-neutral economy. Electrodes made of hierarchical dendritic materials are investigated for the ERC owing to their structural advantages, including large surface areas, presence of facets with low-coordinated atoms, and needle-like tips. Selected examples are presented to illustrate the state-of-the-art investigation of these dendritic electrodes. The mechanisms and the function of the dendritic structure are discussed, combined with a comparison of performance results of ERC. 相似文献
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The electrochemical CO2 reduction reaction (CO2RR) is viewed as a promising way to remove the greenhouse gas CO2 from the atmosphere and convert it into useful industrial products such as methane, methanol, formate, ethanol, and so forth. Single-atom site catalysts (SACs) featuring maximum theoretical atom utilization and a unique electronic structure and coordination environment have emerged as promising candidates for use in the CO2RR. The electronic properties and atomic structures of the central metal sites in SACs will be changed significantly once the types or coordination environments of the central metal sites are altered, which appears to provide new routes for engineering SACs for CO2 electrocatalysis. Therefore, it is of great importance to discuss the structural regulation of SACs at the atomic level and their influence on CO2RR activity and selectivity. Despite substantial efforts being made to fabricate various SACs, the principles of regulating the intrinsic electrocatalytic performances of the single-atom sites still needs to be sufficiently emphasized. In this perspective article, we present the latest progress relating to the synthesis and catalytic performance of SACs for the electrochemical CO2RR. We summarize the atomic-level regulation of SACs for the electrochemical CO2RR from five aspects: the regulation of the central metal atoms, the coordination environments, the interface of single metal complex sites, multi-atom active sites, and other ingenious strategies to improve the performance of SACs. We highlight synthesis strategies and structural design approaches for SACs with unique geometric structures and discuss how the structure affects the catalytic properties.Electrochemical CO2 reduction reaction (CO2RR) is a promising way to remove CO2 and convert it into useful industrial products. Single-atom site catalysts provide opportunities to regulate the active sites of CO2RR catalysts at the atomic level. 相似文献
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Balmer TE Christenson HK Spencer ND Heuberger M 《Langmuir : the ACS journal of surfaces and colloids》2008,24(4):1566-1569
We have measured the adsorption isotherms of water on a single surface of freshly cleaved mica with K+ on the surface, and on mica where the K+ has been exchanged for H+. Using a very sensitive interferometric technique, we have found a significant difference between the two isotherms at submonolayer coverage, for relative vapor pressures p/p0 < 0.5. The K+-mica isotherm shows a pronounced convexity, suggesting distinct adsorption sites, whereas the H+-mica isotherm is flatter. The two isotherms converge above monolayer coverage. The results give a graphic demonstration of the importance of nanoscale surface heterogeneities for vapor adsorption at submonolayer coverage. 相似文献
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Cao Guangwei Cao Xuerui Shan Mengqing Li Mei Zhu Xinli Han Jinyu Ge Qingfeng Wang Hua 《Journal of Solid State Electrochemistry》2022,26(6):1527-1540
Journal of Solid State Electrochemistry - Surface morphology of Cu-based catalysts is considered as an important factor affecting both activity and product selectivity of electrochemical reduction... 相似文献
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Formate and CO are competing products in the two-electron CO2 reduction reaction (2e CO2RR), and they are produced via *OCHO and *COOH intermediates, respectively. However, the factors governing CO/formate selectivity remain elusive, especially for metal–carbon–nitrogen (M–N–C) single-atom catalysts (SACs), most of which produce CO as their main product. Herein, we show computationally that the selectivity of M–N–C SACs is intrinsically associated with the CO2 adsorption mode by using bismuth (Bi) nanosheets and the Bi–N–C SAC as model catalysts. According to our results, the Bi–N–C SAC exhibits a strong thermodynamic preference toward *OCHO, but under working potentials, CO2 is preferentially chemisorbed first due to a charge accumulation effect, and subsequent protonation of chemisorbed CO2 to *COOH is kinetically much more favorable than formation of *OCHO. Consequently, the Bi–N–C SAC preferentially produces CO rather than formate. In contrast, the physisorption preference of CO2 on Bi nanosheets contributes to high formate selectivity. Remarkably, this CO2 adsorption-based mechanism also applies to other typical M–N–C SACs. This work not only resolves a long-standing puzzle in M–N–C SACs, but also presents simple, solid criteria (i.e., CO2 adsorption modes) for indicating CO/formate selectivity, which help strategic development of high-performance CO2RR catalysts.This report discloses a nontrivial role of the CO2 adsorption mode in governing the CO/formate selectivity of single-atom catalysts towards two-electron CO2 reduction. 相似文献
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The increase of atmospheric CO2 concentration has caused many environmental issues. Electrochemical CO2 reduction reaction(CO2RR) has been considered as a promising strategy to mitigate these challenges. The electrocatalysts with a low overpotential, high Faradaic efficiency, and excellent selectivity are of great significance for the CO2RR. Carbon-based materials including metal-free carbon catalysts and metal-based carbon catalysts have shown great p... 相似文献
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G. Dalmata 《Monatshefte für Chemie / Chemical Monthly》1995,126(11):1195-1201
Summary The electroeduction of Zn(II) ions in 1M NaClO4 in the presence of thiolactams has been studied by means of the faradaic impedance method in wide frequency ranges. The standard rate constants are found to be a linear function of the surface excesses of thiolactams. Catalytic activity of thiolactams increases in the following order: thiopyrrolidone, thiopiperidinone, thiocaprolactam; the enthalpies of activation decrease in this order. The differences in the catalytic activity of thiolactams result mainly from the double layer effect.
Zum katalytischen Effekt von Thiolactamen auf die elektrochemische Reduktion von Zn(II)-Ionen
Zusammenfassung Die Elektroeduktion von Zn(II)-Ionen in 1M NaClO4 in Gegenwart von Thiolactamen wurde mittels derFaradayschen Impedanzmethode über große Frequenzbereiche untersucht. Die Standardgeschwindigkeitskonstanten sind eine lineare Funktion der Überschußoberfläche der Thiolactame. Deren katalytische Aktivität steigt in der Reihenfolge Thiopyrrolidon — Thiopiperidinon — Thiocaprolactam; die Aktivierungsenthalpien sinken in der angegebenen Reihenfolge. Die Unterschiede in der katalytischen Aktivität der Thiolactame sind hauptsächlich auf den Doppelschichteffekt zurückzuführen.相似文献
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Kenzo Hiraoka Kazuo Aruga Susumu Fujimaki Shinichi Yamabe 《Journal of the American Society for Mass Spectrometry》1993,4(1):58-64
Thermodynamic data, ΔH n-1, n o and ΔS n-1, n o, for clustering reactions of halide ions X?(X = F, Cl, Br, and I) with N2Owere measured with a pulsed electron beam high-pressure mass spectrometer. In contrast to the fact that CO2 forms a covalent bond with the fluoride ion to yield the fluoroformate ion, FCO2 ?, the interaction between F? and N2O is mainly electrostatic. It was found that the cluster ions F? (N2O)n complete the first shell at n = 6, thus forming an octahedral structure. The difference between F—CO2 ? and F? ... N2O is discussed in terms of Coulombic, exchange, and charge-transfer interactions. The X? (N2O)2 clusters (X = Cl, Br and I) are found to be of C2h symmetry, while F? (N2O)2 is of a twisted form and is slightly asymmetric due to a slight participation of covalency (charge transfer) in the core ion F? ... N2O. 相似文献