The Key Role of pH Value in the Synthesis of Titanate Nanotubes‐Loaded Manganese Oxides as a Superior Catalyst for the Selective Catalytic Reduction of NO with NH₃

Abstract

Titanate nanotubes (TNTs) synthesized by hydrothermal method were increasingly used as the catalyst support for the selective catalytic reduction (SCR) of NO with ammonia. This paper reports the critical process of postwashing to prepare satisfactory TNTs for the uses of SCR catalysts. Herein, alkaline TNTs (TNTs-AL), acidic TNTs (TNTs-AC), and neutral TNTs (TNTs-NE) were synthesized by controlling washing pH value. When these TNTs were utilized as the catalyst supports for manganese oxides (Mn/TNTs-AL, Mn/TNTs-AC, and Mn/TNTs-NE), the key role of pH value was found. Titanate nanosheets, titanate nanorods and titanate nanotubes were dominated in Mn/TNTs-AL, Mn/TNTs-AC, and Mn/TNTs-NE, respectively. MnO2crystal was observed when using TNTs-AC or TNTs-NE as the support. By contrast, Mn3O4and NaNO3were observed when using TNTs-AL as the support. Mn/TNTs-NE showed the best SCR activity, in line with the largest surface area, the best dispersion, and the most active redox property of manganese oxides. Mn/TNTs-AL showed negligible SCR activity, resulting from the minimum surface area, the Mn3O4-dominating crystal structure, and the bad dispersion of manganese oxides.

[Retracted] Role of Nanoparticles in Environmental Remediation: An Insight into Heavy Metal Pollution from Dentistry

“…Ag-doped TiO 2 nanofibers were shown to have increased photodegradation of 2-chlorophenol under UV treatment [111]. In addition, titanates, the inorganic compounds of titanium oxide, were described for the elimination of pollutants [112]. TiO 2 nanoparticles are also used as a catalyst to convert harmful sulphur dioxide (SO2) from atmosphere into sulphur through a chemical reaction.…”

Review on the Recent Applications of Nanomaterials in Energy, Environment and Health Care

“…Titanium oxide materials are used for the removal of contaminants. Chen et al [74] have demonstrated the fabrication of a wide range of titanate nanotubes (TNTs), such as acidic, basic, and neutral nanotubes, through the hydrothermal method of nanomaterial production. Rasalingam et al, [75] recorded the separation method of TiO2-SiO using the silica source from bamboo materials.…”

Nanotechnology for Environmental Remediation: Materials and Applications

“…In addition to titanium oxide materials, titanates (i.e., inorganic compounds of titanium oxide) have also been reported for the removal of contaminants. For instance, Chen et al [ 35 ], reported the fabrication of basic, acidic, and neutral titanate nanotubes (TNTs) by a hydrothermal method, and these materials were evaluated for the catalytic reduction of NO with ammonia. Manganese oxides were loaded to the three TNT formulations to yield Mn-doped titanate nanosheets, titanate nanorods, and titanate nanotubes (i.e., Mn/TNTs) in the case of basic, acidic, and neutral pH media, respectively.…”