1. Alkali metal-resistant mechanism for selective catalytic reduction of nitric oxide over V2O5/HWO catalysts.
- Author
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Kang, Running, He, Junyao, Bin, Feng, Dou, Baojuan, Hao, Qinglan, Wei, Xiaolin, Nam Hui, Kwun, and San Hui, Kwan
- Subjects
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CATALYSTS , *ALKALI metals , *CATALYTIC reduction , *ALKALI metal ions , *NITRIC oxide , *OXALIC acid , *ALKALIES - Abstract
[Display omitted] • The controllable morphology synthesis of hexagonal WO 3 (HWO) was achieved by commercial bacterial cellulose (C). • The obtained V 2 O 5 /HWO-C catalyst exhibits effective resistance to K poisoning and SO 2 , and follows the Langmuir-Hinshelwood mechanism. • The detailed alkali metal-resistant pathways for the distribution of alkali metal ions (K+) on the K-V 2 O 5 /HWO-C catalyst were proposed. A series of V 2 O 5 /HWO catalysts are prepared by hydrothermal and impregnation methods using different precursors, among which the V 2 O 5 /HWO-C catalyst exhibited the optimal NH 3 -SCR performance. Compared to oxalic acid (O) and water (W), commercial bacterial cellulose (C) as a precursor can firstly achieve a more controllable synthesis to form hexagonal WO 3 (HWO) of V 2 O 5 /HWO-C catalyst. Various characterization (XRD, N 2 -BET, TEM, SEM, XPS, EDX mapping, and NH 3 /NO-TPD-MS) indicate that a higher specific surface area, abundant active oxygen and surface acidity result from the V 2 O 5 /HWO-C catalyst. The reason is that HWO-C has an excellent and smooth rod-shaped morphology, which promotes high dispersion of V 2 O 5 on its surface. In situ IR results show that the SCR follows the Langmuir-Hinshelwood (L-H) mechanism, where absorbed NO x intermediate species are formed on the V 2 O 5 and react with the NH 4 + and NH 3abs groups of V 2 O 5 and HWO. After loading 1.75 wt% K+, the obtained K-V 2 O 5 /HWO-C catalyst exhibits effective resistance to K poisoning and SO 2 , and retains 78 % NO x conversion efficiency at 360 °C after 10 h, attributed to the effective capture of K+ (1.04 wt%) in HWO-C channels via a new pathway, although approximately 0.71 wt% K+ are located on HWO-C external surface with weak bonding to V 2 O 5. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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