Selective Catalytic Reduction of NOx with Ammonia: NH3-SCR
Selective Catalytic Reduction of NOx with Hydrocarbons: HC-SCR
Application Research on Diesel Engine Emission Control
Catalytic Purification of Indoor Air Pollutants
Heterogeneous Atmospheric Chemistry
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Catalytic Purification of Indoor Air Pollutants

 

1. Catalytic oxidation of HCHO at room temperature

    

Indoor air quality has a great effect on human health. Above 50% of all illnesses are caused by polluted indoor air. The effect of indoor air quality on health has received increasing concern in recent years. Therefore, it is of great interest to effectively control indoor air pollution. We developed a novel Pt/TiO2 catalyst for ambient HCHO oxidation. Then we observed that the alkali ions could significantly promote the activity of the Pt/TiO2 catalyst by inducing an atomically dispersed Pt species and opening a new low-temperature reaction pathway. New Air Cleaners equipped with this novel catalyst have been developed and put into the Chinese market.

 

1.1 Pt/TiO2 catalyst for ambient HCHO oxidation

 

A highly efficient and stable Pt/TiO2 catalyst was developed for the catalytic oxidation of formaldehyde (HCHO), which for the first time in the world was able to achieve the complete catalytic decomposition of formaldehyde into H2O and CO2 at room temperature with no need for any external energy input. It was demonstrated that the highly dispersed Pt species on TiO2 plays the key role in determining the high activity of the Pt/TiO2 catalyst for ambient HCHO destruction. Also, the reaction mechanism of HCHO oxidation over the noble metal catalyst was elucidated. (Catal. Commun., 2005,6:  211-214., Appl. Catal.B,2006, 65:37-43, Catal. Today, 2007, 126: 345-350)


 

1.2 Alkali ions promote activity of Pt/TiO2

 

It was observed that the alkali ions have a significant promotion effect on the activity of Pt/TiO2 for ambient HCHO oxidation. The Na-free catalyst had low activity for HCHO oxidation, with HCHO conversion being only ca. 19% at room temperature. With 2% Na addition, 100% HCHO conversion to CO2 and H2O was achieved. It was revealed that the alkali ions significantly promote the activity of Pt/TiO2 by inducing an atomically dispersed Pt species, opening up a new low-temperature reaction pathway. (Angew. Chem. Int. Ed. 2012, 51(38): 9628-9632.


1.3 Common promotion effect of alkali ions 

We observed that Na doping also has a dramatic and common promotion effect on Pd/TiO2. It was revealed that Na species addition can induce and further stabilize a negatively charged and well-dispersed Pd species, which then facilitates the activation of H2O and chemisorbed oxygen, resulting in high performance for the Na-doped Pd/TiO2 catalyst in ambient HCHO destruction. (Environ. Sci. Technol., 2014, 48: 5816-5822)

 

1.4 Practical applications of Pt-based catalyst

We have successfully applied this basic research achievement in practical applications. New Air Cleaners equipped with the novel Pt-based catalyst have been developed and put into the Chinese market; they have already become the best-selling Air Cleaner in China, greatly improving indoor air quality and benefitting the Chinese people.


2.Catalytic oxidation of indoor air pollutants-Catalytic oxidation of BTX, Pathogenic microbes and gaseous NH3

 

BTX (benzene, toluene, o-xylene), pathogenic microbes and gaseous ammonia (NH3) are also major indoor air pollutants. Therefore, we are also devoted to the development of catalytic materials for ambient destruction of indoor air BTX, NH3 and microbes. We have developed an integrated system combining adsorption and catalytic oxidation to eliminate indoor air BTX. We also synthesized a series of effective silver-based bactericidal catalysts and elucidated the catalytic disinfection mechanism. In addition, highly efficient catalysts for photocatalytic oxidation of NH3 (PCO-NH3) have also been created for ambient indoor NH3 destruction.

 

2.1 Catalytic oxidation of indoor air pollutants-Catalytic oxidation of BTX (Benzene,Toluene and Xylene)

 

BTX (Benzene, Toluene, and Xylene) are major contaminants in indoor air, thus the removal of these pollutants from indoor air is very important. We developed a series of efficient catalysts for BTX oxidation. An ordered mesoporous Pd/ Co3O4 (3D) catalyst with a more ordered meso structure and higher amount of well-dispersed PdO species showed excellent activity for o-xylene oxidation. The structure-activity relationships of the Pd/Co3O4catalyst were also clearly elucidated. We have also developed a series of Pd-based catalysts with both adsorption capacity and catalytic activity for BTX oxidation. By using a Pd/AC catalyst, we established an adsorption- in situ catalytic oxidation method for indoor air BTX removal, which simplifies the traditional method of "adsorption - desorption - oxidation" to an "adsorption - in situ oxidation" process. (Catal. Today, 2015, 242; 294; Appl. Catal. B, 2013, 72: 142-143; J. Environ. Sci., 2013, 25(6):1206; J. Environ. Sci., 2009, 21: 985; Catal. Today, 2008, 139: 15)


 

2.2 Plasma and Catalysts

 

The effects of different precursors and loading amounts of Mn for preparation of a Mn/Al2O3 catalyst used inplasma-catalytic removal of o-xylene were systematically investigated. Results showed that the Mn/Al2O3 catalyst could efficiently improve o-xylene conversion and decrease the formation of by-products (NOx and O3) with low specific energy density. A Mn/Al2O3 catalyst prepared with a manganese acetate precursor had excellent catalytic activity for o-xylene removal. Among tested loading amounts, the 6 wt% Mn loading amount was the optimum condition for preparation of catalysts for o-xylene conversion. More Mn4+ species, enrichment of lattice oxygen and the presence of a microcrystallineMnO2 phase on the surface of the catalyst were responsible for the high catalytic activity toward oxidation of o-xylene. (Chem. Eng.J., 2016, 288:406-413)

 

2.3 Catalytic disinfection

A series of Ag-loaded catalysts with different crystal phases and shapes were prepared and their bactericidal activities were investigated. The bactericidal effect should be considered as a synergistic action of reactive oxygen species (ROS) produced through activating O2 by catalysts and the toxicity of Ag+ eluted form the catalysts, which couldinduce the production of intracellular ROS, disruption of cell walls and cell membranes, and cell death. FT-IR results also indicated the production of CO2, which proved that catalytic oxidation is the essential mechanism in the bactericidal process. (Environ. Sci. Technol., 2008, 42: 1699-1704; Langmuir, 23: 11197-11199; J. Inorg. Biochem., 2014,135:  45-53; J. Inorg. Biochem., 101: 817-823; J. Inorg. Biochem., 102: 1736-1742. Catal. Commun., 5(3): 170-172; J. Appl. Microbiol., 116:1106-1118; J. Environ. Sci., 2016, 41: 112-120)


 2.4 Photo catalytic oxidation of indoor air ammonia

 

We have developed a series of high-performance TiO2 based catalysts for photo catalytic oxidation of ammonia. Anatase-phase TiO2 calcined at 400 oC was found to have the best performance inNH3 oxidation. It was revealed that surface acidity is the key factor influencing the performance of the catalyst. A surface-fluorinated TiO2 (F-TiO2) catalyst exhibited remarkable activity for NH3 removal, about twice as high as that of the commercial catalyst P25. It was indicated that both the active (001) facets and the surface Ti-F groups contributed to the improvement of the PCO activity, while the surface Ti-F groups play the dominant role. The Ti-F group could retard the recombination of photo generated electrons and holes, which is the major reason for the excellent activity of the F-TiO2 catalyst. ( Appl. Catal. B, 2014, 82:152-153; J. Environ. Sci., 2014, 26: 673)


 

 

Related Papers:

36.  Lian Wang, Changbin Zhang*, Hong He, Fudong Liu, and Caixia Wang, “Effect of doping metals on OMS-2/g- Al2O3 catalysts for plasma catalytic removal of o-Xylene”, J. Phys. Chem. C, 120, (2016), 6136-6144.

35. Yaobin Li, Changbin Zhang, Hong He*, Jianghao Zhang, Min Chen, “Influence of alkali metals on Pd/TiO2 catalysts for catalytic oxidation of formaldehyde at room temperature, Catal. Sci. Technol., 6(7), (2016) 2289-2295.

34. Lian Wang, Hong He*, Changbin Zhang, Li Sun, Sijin Liu, Shaoxin Wang, “Antimicrobial activity of silver loaded MnO2 nanomaterials with different crystal phases against Escherichia coli”, J. Environ. Sci., 41, (2016) 112-120.

33. Lian Wang, Hong He*, Changbin Zhang, Yafei Wang, Bo Zhang, “Effects of precursors for manganese-loaded -Al2O3 catalysts on plasma-catalytic removal of o-xylene”, Chem. Eng. J., 288, (2016) 406-413.

32. Jianghao Zhang, Yaobin Li, Yan Zhang, Min Chen, Lian Wang, Changbin Zhang*, Hong He, “Effect of support on the activity of Ag-based catalysts forformaldehyde oxidation”, Sci. Rep., 5, (2015) 12950.

31. Jianghao Zhang, Yaobin Li, Lian Wang, Changbin Zhang*, Hong He,     “Catalytic oxidation of formaldehyde over manganese oxides with different      crystal structures”, Catal. Sci. Technol., 5, (2015) 2305-2313.

30. Jie Zhang, Changbin Zhang, Hong He*,“Remarkable promotion effect of trace sulfation on OMS-2nanorod catalysts for the catalytic combustion of ethanol ”, J. Environ. Sci., 35, (2015) 69-75.

29. 张洁,张江浩,张长斌,贺泓*,不同晶相结构二氧化锰催化完全氧化乙醇物理化学学报31(2), (2015) 353-359.

28. Yafei Wang, Changbin Zhang, Yunbo Yu, Renliang Yue, Hong He*, “Ordered mesoporous and bulk Co3O4 supported Pd catalysts for catalytic oxidation of o-xylene”, Catal. Today, 242, (2015) 294-299.

27. Lian Wang, Hong He*, Yunbo Yu, Li Sun, Sijin Liu, Changbin Zhang, Lian He,“Morphology-dependent bactericidal activities of Ag/CeO2 catalysts against Escherichia coli”, J. Inorg. Biochem., 135, (2014) 45-53.

26. Lian Wang, Hong He*, Changbin Zhang, Li Sun, Sijin Liu, Renliang Rue,“ Excellent antimicrobial properties of silver-loaded mesoporous silica SBA-15”, J. Appl. Microbiol., 116, (2014) 1106-1118.

25. Changbin Zhang, Yaobin Li, Yafei Wang, Hong He*, “Sodium-promoted Pd/TiO2 for catalytic oxidation of formaldehyde at ambient temperature”, Environ. Sci. Technol., 48, (2014) 5816-5822.

24. Hongmin Wu, Jinzhu Ma, Changbin Zhang*, Hong He, “Effect of TiO2 calcination temperature on the photocatalytic oxidation of gaseous NH3”, J. Environ. Sci., 26, (2014) 673-682.

23. Hongmin Wu, Jinzhu Ma, Yaobin Li, Changbin Zhang*, Hong He, “Photocatalytic oxidation of gaseous ammonia over fluorinated TiO2 with exposed (001) facets”,Appl.Catal. B., 152-153, (2014) 82-87.

22. Yafei Wang, Changbin Zhang, Fudong Liu, Hong He*, “Well-dispersed palladium supported on ordered mesoporous Co3O4 for catalytic oxidation of o-xylene”,Appl.Catal. B., 142-143, (2013) 72-79.

21. Shaoyong Huang, Changbin Zhang*, Hong He, “Effect of pretreatment on Pd/Al2O3 catalyst for catalytic oxidation of o-xylene at low temperature”, J. Environ. Sci., 25, (2013) 1206-1212.

20. Changbin Zhang, Huayu Wang, Fudong Liu, Lian Wang, Hong He*, “Magnetic core–shell Fe3O4@C-SO3H nanoparticle catalyst for hydrolysis of cellulose”, Cellulose, 20,(2013) 127-134.

19. Changbin Zhang, Fudong Liu, Yanping Zhai, Hiroko Ariga, Nan Yi, Yongchun Liu, Kiyotaka Asakura, Maria Flytzani-Stephanopoulos,* Hong He*, Alkali-metal-promoted Pt/TiO2 opens a more efficient pathway to formaldehyde oxidation at ambient temperatures”,Angew. Chem. Int. Ed., 51, (2012) 9628-9632.

18. 张丽,刘福东*,余运波,刘永春,张长斌,贺泓*,“CeO2添加对Ag/Al2O3催化剂低温氨氧化性的影响”, 催化学报, 32, (2011) 727-735.

17. Li Zhang, Hong He*, Mechanism of selective catalytic oxidation of ammonia to nitrogen over Ag/Al2O3, J. Catal., 268, (2009) 18-25.

16. Shaoyong Huang, Changbin Zhang, Hong He*, In situ adsorption-catalysis system for the removal of o-xylene over an activated carbon supported Pd catalyst”, J. Environ. Sci., 21, (2009) 985-990.

15. 张长斌,贺泓*王莲,姜风,刑焕,赵倩,暴伟,负载型贵金属催化剂用于室温催化氧化甲醛和室内空气净化科学通报,54(3), (2009) 278-286.

14. Li Zhang, Changbin Zhang, Hong He*, “The role of silver species in Ag/Al2O3 catalysts for the selective catalytic oxidation of ammonia to nitrogen”, J. Catal., 261, (2009) 101-109.

13.黄韶勇, 张长斌,贺泓*,“Pd/AC催化剂制备及其催化完全氧化邻-二甲苯性能”, 工业催化,16, (2008) 38-45.

12. Shaoyong Huang, Changbin Zhang, Hong He*, “Complete oxidation of o-xylene over Pd/Al2O3 catalyst at low temperature”, Catal. Today, 139, (2008)15-23.

11.Qingyun Chang, Hong He*, Zichuan Ma, “Efficient disinfection of Escherichia coli in water by silver loaded alumina”, J. Inorg. Biochem., 102, (2008) 1736-1742.

10. 常青云, 贺泓*, 曲久辉, 赵进才, “Ag-Ce/AlPO4水中催化杀菌影响因素研究”, 催化学报,29, (2008) 215-220.

9.Qingyun Chang, Hong He*, Jincai Zhao, Min Yang, Jiuhui Qu, “Bactericidal activity of a Ce-promoted Ag/AlPO4 catalyst using molecular oxygen in water”, Environ. Sci. Technol., 42, (2008) 1699-1704.

8. Qingyun Chang, Lizhu Yan, Meixue Chen, Hong He*, Jiuhui Qu, Bactericidal mechanism of Ag/Al2O3against Escherichia coli”, Langmuir,23,(2007) 11197-11199.

7. Changbin Zhang, Hong He*, “A comparative study of TiO2 supported noble metal catalysts for the oxidation of formaldehyde at room temperature”, Catal. Today, 126, (2007) 345-350.

6. Meixue Chen, Lizhu Yan, Hong He*, Qingyun Chang, Yunbo Yu, Jiuhui Qu, “Catalytic sterilization ofEscherichia coli K 12 on Ag/Al2O3 surface”, J. Inorg. Biochem., 101, (2007) 817-823.

5. Changbin Zhang, Hong He*, Shijin Shuai, Jianxin Wang, Catalytic performance of Ag/Al2O3-C2H5OH-Cu/Al2O3 system for the removal of NOx from diesel engine exhaust”, Environ. Pollut.,147, (2007) 415-421.

4. Changbin Zhang, Hong He*, Ken-ichi Tanaka, “Catalytic performance and mechanism of a Pt/TiO2catalyst for the oxidation of formaldehyde at room temperature”, Appl. Catal.B, 65,(2006) 37-43.

3. 闫丽珠, 陈梅雪, 贺泓*,曲久辉, “氧化铝负载银催化剂的杀菌作用”, 催化学报,26(12), (2005) 1122-1126.

2.  Changbin Zhang, Xiaoyan Shi, Hongwei Gao, Hong He*, “The elimination of formaldehyde over Cu-Al2O3 at room temperature”, J. Environ. Sci., 17, (2005) 429-432.

1. Changbin Zhang, Hong He*, Ken-ichi Tanaka, “Perfect catalytic oxidationofformaldehyde over a Pt/TiO2catalyst at room temperature”, Catal. Commun.,6, (2005) 211-214.

 

 
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