Tuning the property of Mn-Ce composite oxides by titanate nanotubes to improve the activity, selectivity and SO2/H2O tolerance in middle temperature NH3-SCR reaction

•The property of Mn-Ce composite oxides was tuned by titanate nanotubes.•This catalyst showed improved activity, selectivity and SO2/H2O tolerance.•The redox property of Mn-Ce composite oxides was tuned in the nano-confined space.

Mn-Ce composite oxides were regarded as a promising alternative to substitute V-based catalysts for the abatement of NOx. However, the obstacles in activity, selectivity and SO2/H2O tolerance still remained. In this paper, titanate nanotubes (TNTs) were used to tune the property of Mn-Ce composite oxides and led to an outstanding catalytic performance in selective catalytic reduction of NO by NH3 within middle temperature region. Compared with conventional MnCe/TiO2 and V2O5/TiO2 nanoparticle catalysts, a higher NO conversion with good SO2/H2O tolerance could be observed at 200-300 °C over the prepared MnCe/TNTs catalyst. More interestingly, much lower N2O concentration was detected in the SCR reaction over this catalyst. Characterization results revealed that MnCe/TNTs had larger BET surface area and greatly enhanced NH3 adsorption, which were beneficial to SCR activity. Moreover, the growth of MnO2 was improved and the redox property of the catalyst was tuned in the nano-confined space of TNTs. Thus the oxidative abstraction of hydrogen from ammonia was suppressed, resulting in less N2O production.

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