Abstract
Exploring a unique structure with superior catalytic performance has remained a severe challenge in many important catalytic reactions. Here, we reported a phenomenon that CeO2-based catalysts loaded with different Pt precursors showed a significant difference in the performance of the reduction of NO with H2. The supported platinum nitrate [PtCe(N)] exhibited a superior low-temperature catalytic performance than the supported chloroplatinic acid [PtCe(C)]. In a wide operating temperature (125–200°C), more than 80% NOx conversion was achieved over PtCe(N) as well as excellent thermal stability. Various characterizations were used to study the microstructure and chemical electronic states. Results showed the introduction of a low valence state of Pt species into the CeO2 resulted in the rearrangement of charges on the surface of CeO2, accompanied by increasing contents of oxygen vacancies and Ce3+ sites. Furthermore, the X-ray photoelectron spectroscopy (XPS) and Raman spectra confirmed that the divalent Pt atom could substitute Ce atom to form the Pt-O-Ce3+ structure, which was the base unit in the high-performance PtCe(N) catalyst. The tunable catalytic system of the Pt-O-Ce3+ structure provides a strategy for the design of supported metal catalysts and may as a model unit for future studies of many other reactions.
Highlights
The use and application of diesel engines in industrial processes became widespread due to their good power performance and economy (Pronk et al, 2009)
The recent examples include the following: (1) a Pt1/FeOx single-atom catalyst showed a higher catalytic performance, which greatly improved the utilization of a single atom (Qiao et al, 2011); (2) single Pt atoms were fixed on the surface of defective TiO2 in which way the increased concentration of oxygen vacancy enhanced photocatalytic performance (Chen et al, 2020); and (3) the insitu formation of a metal bond M-Co (M = Pt, Rh, and Pd) structure during the reaction promoted the reduction of NO (Wang et al, 2013; Nguyen et al, 2016)
These results showed a platinum nitrate precursor supported on CeO2 supports could greatly promote the performance of catalysts at a lower temperature
Summary
The use and application of diesel engines in industrial processes became widespread due to their good power performance and economy (Pronk et al, 2009). Compared to traditional NH3-SCR reaction, H2 as the reductant has advantages of lower temperature activity, cleanliness, and is pollution-free In view of this situation, great effort has been made to reduce NOx. Nakatsuji et al achieved the regeneration of Rh-based catalysts with H2 produced during the strong combustion phase (Nakatsuji and Komppa, 2002). The recent examples include the following: (1) a Pt1/FeOx single-atom catalyst showed a higher catalytic performance, which greatly improved the utilization of a single atom (Qiao et al, 2011); (2) single Pt atoms were fixed on the surface of defective TiO2 in which way the increased concentration of oxygen vacancy enhanced photocatalytic performance (Chen et al, 2020); and (3) the insitu formation of a metal bond M-Co (M = Pt, Rh, and Pd) structure during the reaction promoted the reduction of NO (Wang et al, 2013; Nguyen et al, 2016).
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