d带中心理论怎样解释过渡金属表面吸附强度与催化活性随金属种类的系统变化，以及火山型活性曲线的由来？
How does d-band center theory explain the systematic variation of adsorption strength and catalytic activity across transition-metal surfaces, and where does the volcano-shaped activity pattern come from?
吸附强弱取决于金属d带与吸附质轨道杂化后反键态停留在费米能级以上而空置的程度。d带中心越靠近费米能级，未被占据的反键态越多，吸附键越强；应变、合金化或配体效应平移d带中心即可连续调节吸附强度。依据Sabatier原理，吸附过弱无法活化反应物，过强则中间体难以脱附转化，两端活性都受抑制，唯有中等吸附强度的表面居于火山顶，这为筛选合金与应变催化剂提供了标度关系基础。
Adsorption strength is governed by how much of the antibonding hybrid between the metal d band and the adsorbate orbitals stays vacant above the Fermi level. A d-band center nearer the Fermi energy leaves more antibonding states empty and strengthens the bond, while strain, alloying, or ligand effects shift the center and retune adsorption continuously. By the Sabatier principle, surfaces that bind too weakly never activate the reactants and those that bind too strongly trap the intermediates, so activity peaks at intermediate binding strength - a scaling foundation for screening alloys and strained catalysts.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-03
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B. Hammer、J. K. Nørskov《Theoretical surface science and catalysis - calculations and concepts》，Advances in Catalysis，2000年，第45卷，71页
B. Hammer & J. K. Norskov, Advances in Catalysis, 2000, 45, 71 (DOI: 10.1016/S0360-0564(02)45013-4)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1016/S0360-0564(02)45013-4：Theoretical su
#d带中心 #萨巴蒂尔原理 #吸附强度
工业合成氨铁催化剂中的Al₂O₃与K₂O两种助剂各自起什么作用？为什么两者都要加？
What separate roles do the Al2O3 and K2O promoters play in the iron catalyst for industrial ammonia synthesis, and why are both needed?
Al₂O₃是结构助剂，K₂O是电子助剂，分别负责保住活性表面与降低速控步骤能垒。机理：合成氨的速控步骤是N₂在铁表面的解离吸附，优先发生在Fe(111)等开放台阶位。Al₂O₃分散隔开铁微晶、抑制烧结，维持大比表面积和活性形貌；K₂O向相邻铁原子给电子，提高表面电子密度，削弱N≡N三键并稳定N₂*与N*吸附中间体，降低解离活化能。二者协同才能在400-500°C、10-30 MPa下高效运行。
Alumina is the structural promoter and potash the electronic one: the former preserves the active surface, the latter lowers the barrier of the rate-determining step. That step is dissociative adsorption of N2 on iron, favored at open sites such as Fe(111). Al2O3 separates the iron crystallites and suppresses sintering at operating temperatures, holding a large area and the reactive morphology; K2O donates electron density to neighboring iron atoms, weakening the N≡N triple bond and stabilizing adsorbed N2 and N species, which eases dissociation. Only together do they sustain efficient service at 400-500 °C and 10-30 MPa.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
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出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
K. Honkala、A. Hellman、I. N. Remediakis、J. K. Nørskov等《Ammonia synthesis from first-principles calculations》，Science，2005年，第307卷，555页；G. Ertl因表面催化研究获2007年诺贝尔化学奖
K. Honkala et al., Science, 2005, 307, 555 ; G. Ertl, Nobel Prize in Chemistry 2007
#合成氨 #助催化剂 #表面催化
多相催化的双分子反应中，怎样依据速率对两种反应物分压的依赖关系区分Langmuir-Hinshelwood与Eley-Rideal机理？
For a bimolecular reaction on a heterogeneous catalyst, how does the way the rate depends on each reactant partial pressure tell a Langmuir-Hinshelwood mechanism apart from an Eley-Rideal one?
关键看速率定律中两个分压各自的幂次。LH机理要求两种分子都先吸附、再在表面上相互反应，低覆盖度下速率正比于两分压之积，某一反应物饱和后对其降为零级甚至出现负级数；ER机理只有一种分子吸附，另一分子从气相直接撞上吸附态物种成键，故饱和区对吸附组分呈零级、对气相组分始终保持一级。再用程序升温脱附或同位素标记验证共吸附是否必要，即可可靠判别。
Read off the order with respect to each partial pressure in the rate law. A Langmuir-Hinshelwood route needs both molecules adsorbed before they react on the surface: at low coverage the rate follows the product of the two pressures, and once either reagent saturates the surface its order falls to zero or turns negative. An Eley-Rideal route keeps only one species adsorbed, struck directly by the partner arriving from the gas phase, so in the saturation regime the rate is zero-order in the adsorbate yet strictly first-order in the gas-phase molecule. Temperature-programmed desorption or isotopic labeling that tests whether coadsorption is truly required clinches the assignment.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
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I. Chorkendorff、J. W. Niemantsverdriet《Concepts of Modern Catalysis and Kinetics》，Wiley-VCH，2003年，表面反应动力学章节
I. Chorkendorff & J. W. Niemantsverdriet, Concepts of Modern Catalysis and Kinetics, Wiley-VCH, 2003, chapter on kinetics of surface reactions
独立核验依据 · Independent verification: 核验依据 1 ISBN 9783527812837 (2004)
#表面反应机理 #朗缪尔-欣谢尔伍德 #埃利-里迪尔
质子交换膜燃料电池的铂阳极为什么容易被痕量CO毒化？PtRu合金催化剂为什么能缓解这种中毒？
Why is the platinum anode of a proton-exchange-membrane fuel cell readily poisoned by trace carbon monoxide, and how does a PtRu alloy catalyst ease that poisoning?
CO在铂上的吸附能远高于氢，燃料中百万分之一量级的CO便会抢占氢解离吸附所需的Pt位点并阻断其氧化再生通道，阳极电压随之迅速恶化。PtRu的缓解来自双功能协同加电子调制：Ru在更低电位即可生成Ru-OH含氧物种，相邻Pt上的Pt-CO与其表面反应放出CO2，实现低温氧化再生；同时Ru使Pt的d带中心下移、CO吸附键减弱，双重效应显著拓宽了耐CO的电位窗口。
Carbon monoxide adsorbs on platinum far more strongly than hydrogen, so parts-per-million levels of CO occupy the sites needed for H2 dissociation and block their oxidative regeneration, collapsing anode performance. PtRu relieves this through bifunctional cooperation plus electronic modulation: ruthenium supplies oxygenated Ru-OH species at lower potentials that oxidize neighboring Pt-CO to CO2 and free the sites, while the Ru-induced downshift of the platinum d-band center weakens the Pt-CO bond itself, together widening the potential window the anode can tolerate.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
M. Watanabe、S. Motoo《Electrosynthesis on adatoms: CO oxidation on platinum electrodes with ruthenium adatoms》，J. Electroanal. Chem.，1975年，第60卷，267页
M. Watanabe & S. Motoo, J. Electroanal. Chem., 1975, 60, 267 (bifunctional mechanism of CO oxidation on Pt-Ru)
#一氧化碳中毒 #铂钌催化剂 #双功能机理