催化剂为什么常“担载”在多孔载体上？
Why are catalysts often supported on porous materials?
把少量贵重金属分散在氧化铝等多孔载体上，可大幅提高表面积和利用率，并减少高温烧结失活。
Dispersing a little active metal on porous alumina hugely raises surface area and usage efficiency while resisting high-temperature sintering.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#催化剂载体 #比表面积 #分散
硝酸是怎么从氨造出来的（奥斯特瓦尔德过程）？
How is nitric acid made from ammonia (the Ostwald process)?
氨先在铂铑网催化剂上氧化成一氧化氮，再氧化成二氧化氮，最后溶于水生成硝酸，并副产可循环的一氧化氮。它是工业固定氮的关键路线。
NH3 is first oxidized over a Pt–Rh gauze to NO, then to NO2, which dissolves in water to give HNO3 while recycling NO. It is the key industrial route to fixed nitrogen.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#硝酸 #奥斯特瓦尔德 #催化氧化
沸石为什么是“形状选择”催化剂？
Why are zeolites shape-selective catalysts?
沸石是结晶硅铝酸盐，孔径仅零点几纳米，与有机分子直径同量级，且全晶体尺寸一致。分子要么进得来要么进不来；孔腔限制哪种过渡态容得下，出来的只剩跑得动的异构体，即反应物、过渡态、产物三重择形。铝替硅留负电荷，由可交换阳离子平衡，配质子便是强酸位，催化与择形同在此孔。别把择形算给比表面积：无定形硅铝酸盐面积同样大却不挑分子。
Zeolites are crystalline aluminosilicates whose pores measure only a few tenths of a nanometer, about the diameter of an organic molecule, and that size stays uniform throughout the crystal. A molecule either fits in or it does not; the cavities limit which transition states can be accommodated, and only the isomers that can diffuse out survive - reactant, transition-state and product selectivity. Substituting aluminium for silicon leaves negative charge, balanced by exchangeable cations, which becomes a strong acid site once it carries a proton, so catalysis and shape-selection share the same pore. Selectivity should not be credited to surface area: amorphous aluminosilicates offer the same area yet pick no molecules.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#沸石 #择形催化 #微孔
沸石催化剂为什么能“挑”分子？
How can zeolite catalysts ‘select’ molecules by shape?
沸石是孔径均一的微孔晶体，只有尺寸和形状合适的分子能进入孔道反应，这叫形状选择性，炼油中极有用。
Zeolites are crystalline microporous solids with uniform pores; only molecules of the right size/shape enter and react—shape selectivity, vital in refining.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#沸石 #形状选择性 #微孔
接触法怎样制造硫酸？
How does the contact process make sulfuric acid?
用 V₂O₅ 催化 SO₂ 氧化成 SO₃，再吸收成硫酸；是最大宗的工业催化过程之一。
V₂O₅ catalyzes SO₂ to SO₃, which is then absorbed into sulfuric acid; among the largest industrial catalytic processes.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#接触法 #硫酸 #V2O5
为什么铅会让汽车三元催化器“中毒”？
Why does lead poison a car’s catalytic converter?
铅化合物会覆盖在铂、钯、铑的活性表面上，堵住活性位点使催化剂失效，所以必须用无铅汽油。
Lead compounds coat the platinum, palladium and rhodium surfaces, blocking active sites so the catalyst dies—hence unleaded fuel.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#催化剂中毒 #铅 #三元催化
汽车冷启动时为什么尾气最脏？
Why are cold-start emissions the dirtiest?
催化器要升到“起燃温度”(约250–300°C)才高效，冷车未达温时几乎不工作，污染物直接排出。
The catalyst only works well above its light-off temperature (~250–300 °C); while cold it’s inactive and pollutants pass straight through.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#催化器 #起燃温度 #尾气
为什么工业多用固体(非均相)催化剂？
Why do industries prefer solid (heterogeneous) catalysts?
固体催化剂反应后容易与产物分离、可连续使用、不易污染产品，比溶解态(均相)催化剂更省成本。
Solid catalysts are easy to separate from products, reusable continuously, and don’t contaminate the product—cheaper than dissolved homogeneous ones.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#非均相催化 #分离 #工业
接触法制硫酸为什么用五氧化二钒(V2O5)作催化剂？
Why is vanadium pentoxide (V2O5) used as the catalyst in the contact process?
V2O5在约400°C就能高效催化SO2氧化为SO3，且比铂便宜、不易中毒，是经济又耐用的选择。
V2O5 efficiently catalyzes SO2 → SO3 near 400 °C; it is cheaper than platinum and resists poisoning, making it economical and robust.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Housecroft & Sharpe,《Inorganic Chemistry》第5版,Pearson,2018
C. E. Housecroft and A. G. Sharpe, Inorganic Chemistry, 5th ed., Pearson, 2018
#催化剂 #五氧化二钒 #硫酸
哈伯法合成氨的铁催化剂中，Al2O3与K2O两种助剂分别起什么作用？
In the Haber-Bosch ammonia synthesis, what roles do the Al2O3 and K2O promoters play in the iron catalyst?
Al2O3是结构助剂，分散在铁微晶之间，阻止高温高压运行中铁粒子的烧结长大，从而维持催化剂的大比表面积和多孔结构。K2O是电子助剂，向邻近的铁部位供给电子，增强铁对吸附态氮分子的反馈电子能力，削弱N≡N三重键，降低速控步骤即氮的解离吸附的活化能。两类助剂协同作用，使合成氨在450℃左右具备工业可行的速率。
Alumina serves as the structural promoter: dispersed among iron crystallites, it impedes sintering and grain growth during operation at high temperature and pressure, maintaining the catalyst's large specific surface area and porous texture. Potassium oxide is the electronic promoter, donating electron density to neighboring iron sites so that back-donation into adsorbed dinitrogen strengthens, the NN triple bond weakens, and the activation energy of the rate-limiting dissociative adsorption falls. Acting together, they make synthesis viable near 450 degrees Celsius.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
《现代催化与动力学概念》，Chorkendorff 与 Niemantsverdriet 著，第2版，Wiley-VCH，2007年
Concepts of Modern Catalysis and Kinetics, I. Chorkendorff & J. W. Niemantsverdriet, 2nd ed., Wiley-VCH, 2007
独立核验依据 · Independent verification: 核验依据 1 ISBN 9783527812837 (2004)
#合成氨 #助催化剂 #氮气解离吸附
汽车三元催化器如何在一次通过中同时去除CO、烃类和NOx？铂与铑分别承担什么任务？
How does a three-way automotive catalytic converter remove CO, hydrocarbons and NOx in a single pass, and what tasks do platinum and rhodium each perform?
Pt–Pd–Rh颗粒负载在涂层的陶瓷蜂窝载体上分工协作：铂钯把CO与未燃烃氧化成CO₂和H₂O；铑对NO吸附更强，可将N—O键解离，相邻表面氮原子再复合成N₂脱附，抑制N₂O与NH₃副产。上游氧传感器闭环控制把空燃比锁定在化学计量比附近的窄窗（λ≈1）内，三类污染物转化率才能同时超过90%。早年汽油含铅会毒化表面，这正是推广无铅汽油的原因。
Pt–Pd–Rh particles dispersed on a washcoated ceramic honeycomb work in series. Platinum and palladium oxidise CO and unburnt hydrocarbons to CO₂ and H₂O. Rhodium adsorbs NO strongly enough to cleave the N–O bond; adjacent surface nitrogen atoms then recombine and desorb as N₂, suppressing N₂O and NH₃ by-products. A closed-loop oxygen sensor holds the air–fuel ratio inside the narrow window around stoichiometry (λ ≈ 1), where all three conversions exceed 90% simultaneously. Lead additives once poisoned the active surface, which is why unleaded petrol was mandated.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Kašpar J., Fornasiero P., Hickey N., Catalysis Today, 2003, 77:419–449（DOI: 10.1016/S0920-5861(02)00384-X）
J. Kašpar, P. Fornasiero & N. Hickey, Catalysis Today, 2003, 77:419–449 (DOI: 10.1016/S0920-5861(02)00384-X)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1016/S0920-5861(02)00384-X：Automotive cat
#三元催化 #NOx还原 #蜂窝陶瓷载体