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Eppur Si Riscalda - and yet, It (Just) Heats Up: Further Comments on “Quantifying Hot Carrier and Thermal Contributions in Plasmonic Photocatalysis” Eppur Si Riscalda -然而,它(只是)升温:对“等离子体光催化中热载流子和热贡献的量化”的进一步评论
Pub Date : 2019-07-10 DOI: 10.26434/chemrxiv.8850518.v1
Y. Sivan, J. Baraban, Y. Dubi
Our Comment [1] on recent attempts to distinguish thermal and non-thermal (``hot carrier'') contributions to plasmon-assisted photocatalysis [2] initiated a re-evaluation process of previous literature on the topic within the nano-plasmonics and chemistry communities. The Response of Zhou et al [3] attempts to defend the claims of the original paper [2].

In this manuscript, we show that the Response [3] presents additional data that further validates our central criticism: inaccurately measured temperatures (that are lower than the actual temperature of the catalyst) led Zhou etal to incorrectly claim conclusive evidence of non-thermal effects. We identify flaws in the experimental setup (e.g. the use of the default settings for the thermal camera and incorrect positioning of the thermometer) that may have led Zhou et al to make such claims. We further show that the Response contains several factual errors and does not address the technical problems we identified with the data acquisition in [2]. We demonstrate that both the Response [3] and the original paper [2] contain additional faults, for example, in the power determination and in the normalization of the rate to the catalyst volume, and exhibit misconceptions regarding the thermo-optic response of metal nanostructures. The burden of proof required by the proposal of a novel physical mechanism has simply not been met, especially when the existing data can be modeled exquisitely by conventional theory.
[1] Y. Sivan, J. Baraban, I. W. Un & Y. Dubi, Science Vol. 364, Issue 6439, eaaw9367. https://science.sciencemag.org/content/364/6439/eaaw9367.abstract


我们的评论[1]最近试图区分等离子体辅助光催化的热和非热(“热载流子”)贡献[2],这引发了对纳米等离子体和化学领域先前关于该主题的文献的重新评估过程。Zhou等人[3]的Response试图为原论文[2]的观点辩护。在这篇论文中,我们表明Response[3]提供了额外的数据,进一步验证了我们的核心批评:不准确的测量温度(低于催化剂的实际温度)导致Zhou etal错误地声称非热效应的确凿证据。我们发现了实验设置中的缺陷(例如使用热像仪的默认设置和温度计的不正确定位),这可能导致Zhou等人做出这样的声明。我们进一步表明,回应包含几个事实错误,并没有解决我们在[2]中发现的数据采集技术问题。我们证明了Response[3]和原始论文[2]都包含额外的错误,例如,在功率确定和催化剂体积速率的归一化方面,并且对金属纳米结构的热光学响应表现出误解。提出一种新的物理机制所要求的举证责任根本没有得到满足,特别是当现有的数据可以用传统理论精确地建模时。[1]Y. Sivan, J. Baraban, I. W. Un & Y. Dubi,《科学》第364卷,第6439期,eaaw9367。https://science.sciencemag.org/content/364/6439/eaaw9367.abstract [2] https://science.sciencemag.org/content/362/6410/69[3] https://science.sciencemag.org/content/364/6439/eaaw9545
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引用次数: 1
Non-Uniqueness of Parameters Extracted from Resonant Second-Order Nonlinear Optical Spectroscopies. 二阶共振非线性光谱参数提取的非唯一性。
Pub Date : 2019-05-15 DOI: 10.1021/jp908240d
B. Busson, A. Tadjeddine
Experimental data from second-order nonlinear optical spectroscopies (SFG, DFG, and SHG) provide parameters relevant to the physical chemistry of interfaces and thin films. We show that there are in general 2 N or 2 N-1 equivalent sets of parameters to fit an experimental curve comprising N resonant features, of vibrational or electronic origin for example. We provide the algorithm to calculate these sets, among which the most appropriate has to be selected. The main consequences deal with the existence of "ghost resonances", the need of a critical analysis of fit results, and the procedure to search for better sets of parameters coherent with applied constraints.
二阶非线性光谱(SFG, DFG和SHG)的实验数据提供了与界面和薄膜的物理化学相关的参数。我们表明,通常有2个N或2个N-1等效的参数集来拟合包含N个共振特征的实验曲线,例如振动或电子起源。我们提供了计算这些集合的算法,必须从中选择最合适的集合。主要结果涉及“幽灵共振”的存在,对拟合结果进行批判性分析的需要,以及寻找与应用约束相一致的更好的参数集的程序。
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引用次数: 43
Direct CO2 Electroreduction from Carbonate 碳酸盐直接电还原CO2
Pub Date : 2019-05-06 DOI: 10.26434/chemrxiv.8081777
Yuguang C. Li, Geonhui Lee, T. Yuan, Ying Wang, Dae-Hyun Nam, Ziyun Wang, F. P. G. Arquer, Yanwei Lum, C. Dinh, O. Voznyy, E. Sargent
The process of CO2 valorization – all the way from capture/concentration of CO2 to its electrochemical upgrade - requires significant inputs in each of the capture, upgrade, and separation steps. The gas-phase CO2 feed following the capture-and-release stage and into the CO2 electroreduction stage produce a large waste of CO2 (between 80 and 95% of CO2 is wasted due to carbonate formation or electrolyte crossover) that adds cost and energy consumption to the CO2 management aspect of the system. Here we report an electrolyzer that instead directly upgrades carbonate electrolyte from CO2 capture solution to syngas, achieving 100% carbon utilization across the system. A bipolar membrane is used to produce proton in situ, under applied potential, which facilitates CO2 releasing at the membrane:catalyst interface from the carbonate solution. Using an Ag catalyst, we generate pure syngas at a 3:1 H2:CO ratio, with no CO2 dilution at the gas outlet, at a current density of 150 mA/cm2, and achieve a full cell energy efficiency of 35%. The direct carbonate cell was stable under a continuous 145 h of catalytic operation at ca. 180 mA/cm2. The work demonstrates that coupling CO2 electrolysis directly with a CO2 capture system can accelerate the path towards viable CO2 conversion technologies.
二氧化碳的增值过程——从二氧化碳的捕获/浓缩到其电化学升级——在每个捕获、升级和分离步骤中都需要大量的投入。在捕获和释放阶段之后的气相CO2进料进入CO2电还原阶段会产生大量的CO2浪费(由于碳酸盐形成或电解质交叉,80%至95%的CO2被浪费),这增加了系统二氧化碳管理方面的成本和能源消耗。在这里,我们报告了一种电解槽,它可以直接将碳酸盐电解质从二氧化碳捕获溶液升级为合成气,在整个系统中实现100%的碳利用率。双极膜在施加电位下产生质子,促进二氧化碳在膜-催化剂界面从碳酸盐溶液中释放出来。我们使用Ag催化剂,以3:1的H2:CO比生成纯合成气,在排气口不稀释CO2,电流密度为150 mA/cm2,并实现35%的全电池能量效率。在180 mA/cm2的催化下,直接碳酸盐电池在145 h的连续催化下是稳定的。这项工作表明,将二氧化碳电解直接与二氧化碳捕获系统耦合可以加速实现可行的二氧化碳转化技术。
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引用次数: 2
Sodium Metal Battery using CobaltOxide through in Situ Plating of Sodium Metal 金属钠原位镀钴金属钠电池
Pub Date : 2018-10-02 DOI: 10.13140/RG.2.2.15903.20646
Saurav L. Chaudhari, Ketan P Pise
In this work, we demonstrate that an impugn of energy density for sodium chemistries can be prevail through an anode-free architecture enabled by the use of a (nanocarbon/Cobaltoxide) nucleation layer formed on Aluminium current collectors. Electrochemical studies show this configuration to provide highly stable and efficient plating and stripping of sodium metal over a range of currents up to 5 mA/cm2, sodium loading up to 14 mAh/cm2, and with long-term endurance exceeding 1000 cycles at a current of 0.7 mA/cm2. Building upon this anode-free architecture, we demonstrate a full cell using a presodiated pyrite cathode to achieve energy densities of 400 Wh/kg, far surpassing recent reports on SIBs and even the theoretical maximum for LIB technology while still relying on naturally abundant raw materials and cost-effective aqueous processing.
在这项工作中,我们证明了钠化学的能量密度可以通过使用铝集流器上形成的(纳米碳/钴氧化物)成核层实现无阳极结构来实现。电化学研究表明,这种配置可以在高达5 mA/cm2的电流范围内提供高度稳定和高效的镀和剥离钠金属,钠负载高达14 mAh/cm2,并且在0.7 mA/cm2的电流下具有超过1000次的长期耐用性。在这种无阳极结构的基础上,我们展示了一个使用沉淀的黄铁矿阴极的完整电池,其能量密度达到400 Wh/kg,远远超过了最近关于sib的报道,甚至是LIB技术的理论最大值,同时仍然依赖于天然丰富的原材料和具有成本效益的水处理。
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引用次数: 0
A Transferable Machine-Learning Model of the Electron Density 电子密度的可转移机器学习模型
Pub Date : 2018-09-14 DOI: 10.26434/chemrxiv.7093589.v1
Andrea Grisafi, Alberto Fabrizio, Benjamin Meyer, D. Wilkins, C. Corminboeuf, M. Ceriotti
We introduce an atom-centered, symmetry-adapted framework to machine-learn the valence charge density based on a small number of reference calculations. The model is highly transferable, meaning it can be trained on electronic-structure data of small molecules and used to predict the charge density of larger compounds with low, linear-scaling cost.
我们在少量参考计算的基础上引入了一个以原子为中心、对称适应的框架来机器学习价电荷密度。该模型具有高度可转移性,这意味着它可以在小分子的电子结构数据上进行训练,并以低线性缩放成本用于预测较大化合物的电荷密度。
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引用次数: 156
Alchemical perturbation density functional theory 炼金术微扰密度泛函理论
Pub Date : 2018-09-05 DOI: 10.1103/physrevresearch.2.023220
G. F. von Rudorff, O. A. von Lilienfeld
We introduce an orbital free electron density functional approximation based on alchemical perturbation theory. Given convergent perturbations of a suitable reference system, the accuracy of popular self-consistent Kohn-Sham density functional estimates of properties of new molecules can be systematically surpassed---at negligible cost. The associated energy functional is an approximation to the integrated energy derivative, requiring only perturbed reference electron densities: No self-consistent field equations are necessary to estimate energies and electron densities. Electronic ground state properties considered include covalent bonding potentials, atomic forces, as well as dipole and quadropole moments.
提出了基于炼金术微扰理论的轨道自由电子密度泛函近似。给定一个合适的参照系的收敛摄动,流行的自洽Kohn-Sham密度泛函估计新分子性质的准确性可以被系统地超越——成本可以忽略不计。相关的能量泛函是积分能量导数的近似值,只需要摄动参考电子密度:不需要自洽场方程来估计能量和电子密度。考虑的电子基态性质包括共价键势,原子力,以及偶极和四极矩。
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引用次数: 19
水的结构和反常物性 = Perspective : structures and properties of liquid water 水的结构和反常物性 = Perspective : structures and properties of liquid water
Pub Date : 2018-09-03 DOI: 10.7536/PC171013
Lei Li, Chuanggang Yao, Xi Zhang, Yongli Huang, Zengsheng Ma, Changqing Sun
Introduction of the principles of the asymmetrical, short-range O:H-O coupled oscillater pair and the basic rule for water ice, which reconciles the structure and anomalies of water ice.
介绍了不对称短程O:H-O耦合振子对的原理和水冰的基本规律,调和了水冰的结构和异常。
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引用次数: 0
Excimer laser cleaning of black sulphur encrustation from silver surface. 准分子激光清洗银表面黑硫结壳。
Pub Date : 2018-08-16 DOI: 10.1016/j.optlastec.2018.12.012.
M. Raza, Sankha Shuvra Das, Parimal Tudu, P. Saha
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引用次数: 2
The fundamentals of quantum machine learning 量子机器学习的基本原理
Pub Date : 2018-07-11 DOI: 10.1007/978-3-319-42913-7_67-1
B. Huang, Nadine O. Symonds, O. A. V. Lilienfeld
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引用次数: 13
Solar Energy Harvesting with Carbon Nitrides: Do We Understand the Mechanism? 利用氮化碳收集太阳能:我们了解其机制吗?
Pub Date : 2018-07-09 DOI: 10.26434/chemrxiv.6843812.v1
W. Domcke, Johannes Ehrmaier, A. Sobolewski
The photocatalytic splitting of water into molecular hydrogen and molecular oxygen with sunlight is the dream reaction for solar energy conversion. Since decades, transition-metal-oxide semiconductors and supramolecular organometallic structures have been extensively explored as photocatalysts for solar water splitting. More recently, polymeric carbon nitride materials consisting of triazine or heptazine building blocks have attracted considerable attention as hydrogen-evolution photocatalysts. The mechanism of hydrogen evolution with polymeric carbon nitrides is discussed throughout the current literature in terms of the familiar concepts developed for photoelectrochemical water splitting with semiconductors since the 1970s. We discuss in this perspective an alternative mechanistic paradigm for photoinduced water splitting with carbon nitrides, which focusses on the specific features of the photochemistry of aromatic N-heterocycles in aqueous environments. It is shown that a water molecule which is hydrogen-bonded to an N-heterocycle can be decomposed into hydrogen and hydroxyl radicals by two simple sequential photochemical reactions. This concept is illustrated by first-principles calculations of excited-state reaction paths and their energy profiles for hydrogen-bonded complexes of pyridine, triazine and heptazine with a water molecule. It is shown that the excited-state hydrogen-transfer and hydrogen-detachment reactions are essentially barrierless, in sharp contrast to water oxidation in the electronic ground state, where high barriers prevail. We also discuss in some detail the products of possible reactions of the highly reactive hydroxyl radicals with the chromophores. We hypothesize that the challenge of efficient solar hydrogen generation with carbon-nitride materials is less the decomposition of water as such, but rather the controlled recombination of the photogenerated radicals to the closed-shell products H2 and H2O2.
利用阳光将水催化分解为氢分子和氧分子是太阳能转化的理想反应。几十年来,过渡金属氧化物半导体和超分子有机金属结构作为太阳能水分解的光催化剂得到了广泛的探索。最近,由三嗪或七嗪组成的聚合物氮化碳材料作为析氢光催化剂引起了相当大的关注。从20世纪70年代以来发展起来的与半导体进行光电化学水分解的熟悉概念出发,在目前的文献中讨论了聚合物碳氮化物的析氢机制。我们从这个角度讨论了氮化碳光诱导水分裂的另一种机制范例,重点讨论了芳香族n杂环在水环境中的光化学特征。结果表明,与n-杂环成氢键的水分子可以通过两个简单的顺序光化学反应分解为氢自由基和羟基自由基。用第一性原理计算了吡啶、三嗪和七嗪与水分子的氢键配合物的激发态反应路径及其能量分布。结果表明,激发态的氢转移和氢分离反应基本上是无势垒的,与电子基态的水氧化形成鲜明对比,在基态中,高势垒普遍存在。我们还详细讨论了高活性羟基自由基与发色团可能反应的产物。我们假设,利用碳氮材料高效太阳能制氢的挑战不在于水本身的分解,而在于将光生成的自由基控制重组为闭壳产物H2和H2O2。
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引用次数: 0
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arXiv: Chemical Physics
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