钕改性铁基催化剂用于氮氧化物脱除

doi:10.19964/j.issn.1006-4990.2022-0366

摘要/Abstract

摘要：

采用分步浸渍法，分两步将金属铁和钕依次引入商业化成品二氧化钛表面，研究其脱硝性能。通过X射线衍射（XRD）、氮气吸附-脱附（N₂-BET）、X射线光电子能谱（XPS）、氨程序升温脱附（NH₃-TPD）、氢气程序升温还原（H₂-TPR）等方法对样品进行表征分析。通过氮气吸附-脱附发现，钕的引入使得负载铁后的催化剂比表面积减小。X射线衍射分析结果表明，引入的金属物种在催化剂表面具有良好的分散性。氨程序升温脱附测试结果显示，钕的引入增加了催化剂的总酸量，同时改变了催化剂的酸性分布。X射线光电子能谱测试结果表明，钕改性增加了催化剂表面吸附氧和铁（Ⅱ）的含量，有利于脱硝反应的进行。氢气程序升温还原测试结果表明，钕的引入使得催化剂氧化还原性能略有下降。活性测试结果表明，适量钕负载有利于提升催化剂的脱硝性能，钕元素在催化剂中的质量分数为9%时催化剂表现最优，最佳脱硝效率为81.4%。

关键词: 选择性催化还原, 负载型催化剂, 钕, 铁基催化剂

Abstract:

Metal Fe and Nd were introduced into the surface of commercial TiO₂ by stepwise impregnation to study its denitrification performance.The samples were characterized by X-ray diffraction（XRD），nitrogen adsorption-desorption（N₂-BET），X-ray photoelectron spectroscopy（XPS），ammonia temperature-programmed desorption（NH₃-TPD），hydrogen temperature-programmed reduction（H₂-TPR）.The adsorption and desorption of N₂ showed that the introduction of Nd reduced the specific surface area of the catalysts loaded with Fe.X-ray diffraction analysis showed that the introduced metal species had good dispersion on the catalyst surface.The results of NH₃-TPD test showed that the introduction of Nd increased the total acid content of the catalyst and changed the acid distribution of the catalyst.XPS results showed that Nd modification increased the content of oxygen and Fe²⁺ on the surface of the catalyst，which was beneficial to the denitrification reaction.H₂-TPR test showed that the introduction of Nd reduced the redox performance of the catalyst slightly.The results of activity test showed that appropriate Nd loading was beneficial to improve the denitrification performance of the catalyst.When the mass fraction of Nd element in the catalyst was 9%，the catalyst had the best denitrification efficiency of 81.4%.

Key words: selective catalytic reduction, supported catalyst, neodymium, Fe-based catalyst

中图分类号:

O643.3

李鹏, 杨思远, 罗仕忠, 杜沛佞, 谭仁俊, 敬方梨. 钕改性铁基催化剂用于氮氧化物脱除[J]. 无机盐工业, 2023, 55(3): 140-146.

LI Peng, YANG Siyuan, LUO Shizhong, DU Peining, TAN Renjun, JING Fangli. Neodymium-modified iron-based catalysts for nitrogen oxides removal[J]. Inorganic Chemicals Industry, 2023, 55(3): 140-146.

图/表 13

图1

表1

图2

表2

图3

表3

图4

图5

表4

图6

图7

表5

图8

参考文献 13

1	ZHANG Runduo， LIU Ning， LEI Zhigang，et al.Selective transformation of various nitrogen-containing exhaust gases toward N₂ over zeolite catalysts[J].Chemical Reviews，2016，116（6）:3658-3721.
2	BAE S W， ROH S A， KIM S D.NO removal by reducing agents and additives in the selective non-catalytic reduction（SNCR） process[J].Chemosphere，2006，65（1）:170-175.
3	FANG De， QI Kai， LI Fengxiang.Excellent sulfur tolerance performance over Fe-SO₄/TiO₂ catalysts for NH₃-SCR:Influence of sulfation and Fe-based sulfates[J].Journal of Environmental Chemical Engineering，2022，10（1）.Doi:10.1016/j.jece.2021.107038.
4	WANG Fang， GUI Keting， YAO Guihuan.The comparison of selective catalytic reduction of de-NO _x on iron-based materials[C]//Asia-Pacific Power and Energy Engineering Conference （APPEEC），2009:2434-2436.
5	KATO A， MATSUDA S， KAMO T，et al.Reaction between NO _x and NH₃ on iron oxide-titanium oxide catalyst[J].The Journal of Physical Chemistry，1981，85（26）:4099-4102.
6	HUANG Li， ZONG Yuhao， WANG Hu，et al.Effect of neodymium addition on plate-type V₂O₅-MoO₃/TiO₂ catalyst for selective catalytic reduction of NO[J].Rare Metal Materials and Engineering，2021，50（2）:0475-0482.
7	XIE Shangzhi， LI Lulu， JIN Lijian，et al.Low temperature high activity of M（M=Ce，Fe，Co，Ni） doped M-Mn/TiO₂ catalysts for NH₃-SCR and in situ DRIFTS for investigating the reaction mechanism[J].Applied Surface Science，2020，515.Doi:10.1016/j.apsusc.2020.146014.
8	WU Xu， WANG Ruonan， DU Yaili，et al.Performance enhancement of NH₃-SCR via employing hydrotalcite-like precursor to induce the decoration of NiO by TiO₂ phase[J].Molecular Catalysis，2019，467:150-160.
9	THIRUPATHI B， SMIRNIOTIS P G.Nickel-doped Mn/TiO₂ as an efficient catalyst for the low-temperature SCR of NO with NH₃:Catalytic evaluation and characterizations[J].Journal of Catalysis，2012，288:74-83.
10	FAN Zhaoyang， SHI Jianwen， GAO Chen，et al.Gd-modified MnO_x for the selective catalytic reduction of NO by NH₃:The promoting effect of Gd on the catalytic performance and sulfur resistance[J].Chemical Engineering Journal，2018，348:820-830.
11	MA Ziran， WU Xiaodong， FENG Ya，et al.Effects of WO₃ doping on stability and N₂O escape of MnO _x -CeO₂ mixed oxides as a low-temperature SCR catalyst[J].Catalysis Communications，2015，69:188-192.
12	XIE Shangzhi， LI Lulu， JIN Lijian，et al.Low temperature high activity of M（M=Ce，Fe，Co，Ni） doped M-Mn/TiO₂ catalysts for NH₃-SCR and in situ DRIFTS for investigating the reaction mechanism[J].Applied Surface Science，2020，515.Doi:10.1016/j.apsusc.2020.146014.
13	WU Jiahui， JIN Shuanglin， WEI Xudong，et al.Enhanced sulfur resistance of H₃PW₁₂O₄₀-modified Fe₂O₃ catalyst for NH₃-SCR:Synergistic effect of surface acidity and oxidation ability[J].Che-mical Engineering Journal，2021，412.Doi:10.1016/j.cej.2021.128712.

催化剂	D_A/nm	D_B/nm
TiO₂	50.1	51.8
Fe-TiO₂	58.3	59.1
1.8%Nd-Fe/TiO₂	58.9	47.4
9%Nd-Fe/TiO₂	61.2	52.3
18%Nd-Fe/TiO₂	55.8	54.5

催化剂	S_BET/（m²·g^-1）	V_P/（cm³·g^-1）	D_BJH/nm
TiO₂	12.2	0.05	15.9
Fe-TiO₂	22.5	0.11	18.7
1.8%Nd-Fe/TiO₂	20.8	0.10	19.7
9%Nd-Fe/TiO₂	15.6	0.08	20.4
18%Nd-Fe/TiO₂	14.3	0.07	19.3

催化剂	NH₃脱附量/（mmol·g^-1）
催化剂	150~300 ℃	300~600 ℃	600~800 ℃	总计
TiO₂	0.006	0.003	—	0.009
Fe-TiO₂	—	0.009	—	0.009
1.8%Nd-Fe/TiO₂	—	0.025	—	0.025
9%Nd-Fe/TiO₂	0.010	0.019	0.006	0.035
18%Nd-Fe/TiO₂	0.009	0.045	0.016	0.070

催化剂	n（Fe²⁺）/n（Fe³⁺）	n（O_Ⅰ）/n（O_Ⅱ）/n（O_Ⅲ）
Fe-TiO₂	69.5/30.5	19.2/77.3/3.5
1.8%Nd-Fe/ TiO₂	76.0/24.0	19.3/73.2/7.5
9%Nd-Fe/ TiO₂	79.9/20.1	27.6/63.1/9.3
18%Nd-Fe/ TiO₂	79.5/20.5	25.6/48.8/25.6

催化剂	H₂消耗量/（mmol·g^-1）
催化剂	100~550 ℃	550~800 ℃	总计
Fe-TiO₂	2.42	—	2.42
1.8%Nd-Fe/ TiO₂	1.49	1.68	3.17
9%Nd-Fe/ TiO₂	0.50	2.54	3.04
18%Nd-Fe/ TiO₂	1.52	1.49	3.01

首页

全国无机盐信息中心

中国化工学会

无机酸碱盐专业委员会