Effect of Zirconia on Hydrothermally Synthesized Co3O4/TiO2 Catalyst for NOx Reduction from Engine Emissions

Abstract

Effect of zirconia on the 6 wt.% Co3O4/TiO2 catalyst for NOx reduction is investigated in this paper. Co3O4/TiO2 catalyst was prepared by using hydrothermal method and then was promoted with zirconia by impregnation to get 8% wt. ZrO2-Co3O4/TiO2 catalyst. Catalysts were characterized by using XRD, SEM, and TGA. Catalysts real time activity was tested by coating them on stainless steel wire meshes, containing them in a mild steel shell and mounting them at the exhaust tailpipe of a 72 cm3 motorcycle engine. Zirconia promoted catalyst showed higher conversion efficiency of NOX than the simple Co3O4/TiO2 catalyst due to small crystalline size, fouling inhibition and thermal stability.

Synthesis of Highly Efficient and Recyclable Bimetallic Cox–Fe1–x–MOF for the Synthesis of Xanthan and Removal of Toxic Pb2+ and Cd2+ Ions

“…The XRD patterns of the monometallic sample showed peaks located at 2θ = 9.3, 10.2, 11.6, 12.8, 16.8, 18.2, 19.4, 20.3, 22.7, 29.3, 33.5, and 41.6°, which are in good agreement with the XRD patterns of pure Fe–MOF. ,− On the other hand, the XRD patterns of bimetallic Co x –Fe 1– x –MOF showed similar diffraction peaks to Fe–MOF. In addition, new diffraction peaks were detected at 2θ = 9.7, 14.1, 15.8, 20.4, and 21.7° reflecting to Co–MOF. , However, new peaks were observed at 19.4, 44.4, and 69.1° with increasing cobalt content to Co 0.75 –Fe 0.25 –MOF, indicating the aggregation of cobalt oxide crystals on the surface of the sample. , Also, the positions of some peaks were changed with changed molar ratios of Co and Fe ions, especially the peak located at 10.2°, indicating the mutual effect of combination between Fe and Co ions with the linker . It is worth noting that the intensity of peaks at 9.3, 9.8, and 10.2° increased after the addition of Co ions (Figure ).…”

“…m is the sample weight (g) and V (L) is the solution volume. 44,45 Also, the positions of some peaks were changed with changed molar ratios of Co and Fe ions, especially the peak located at 10.2°, indicating the mutual effect of combination between Fe and Co ions with the linker. 13 It is worth noting that the intensity of peaks at 9.3, 9.8, and 10.2°increased after the addition of Co ions (Figure 1).…”

Sustainable and Environmental Catalysis

“…The slightly lower efficiency of zirconia-promoted catalyst towards HCs is due to the nonavailability of the vacancies of oxygen for oxidation on Co 3 O 4 . Both catalysts showed selectivity towards CO, NO x , and HC, and had comparable performance with respect to the activity of a conventional catalyst [18].…”

Synthesis and Characterization of Enhanced Photocatalytic Activity with Li+-Doping Nanosized TiO2 Catalyst

“…4 Hence, it has been widely applied in all sorts of applications such as sewage treatment, gas purification, and environmental protection. 3,5,6 There are four natural polymorphs of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), brookite (orthorhombic), and TiO 2 (monoclinic), 7 of which rutile is more stable than others while three other forms are metastable. 6 It also confirmed that anatase TiO 2 has higher photocatalytic activity than rutile TiO 2 .…”

“…Titanium dioxide (TiO 2 ) is considered to be the most efficient and environmental-friendly photocatalyst − because of its particular combination of low budget, chemical stability, nonpoisonous, high reactivity, favorable stability against photocorrosion, and further amelioration of functionalization . Hence, it has been widely applied in all sorts of applications such as sewage treatment, gas purification, and environmental protection. ,, There are four natural polymorphs of TiO 2 , namely, anatase (tetragonal), rutile (tetragonal), brookite (orthorhombic), and TiO 2 (monoclinic), of which rutile is more stable than others while three other forms are metastable . It also confirmed that anatase TiO 2 has higher photocatalytic activity than rutile TiO 2 . , When irradiated with UV light, TiO 2 shows strong oxidation property and reducing capacity.…”