MnO_x–CeO_x Nanoparticles Supported on Porous Hexagonal Boron Nitride Nanoflakes for Selective Catalytic Reduction of Nitrogen Oxides

Abstract

In selective catalytic reduction (SCR) technology, aggregation of the catalyst generally degrades the performance for converting nitrogen oxides into harmless gases. To avoid such performance degradation and to achieve a noticeable improvement in the SCR performance, good dispersion of the catalyst on the support is required. In this study, we synthesized MnO x −CeO x catalytic nanoparticles on surface-modified supports and studied the dispersion behavior of the catalyst on the support. Hexagonal boron nitride (h-BN) was adopted as the catalyst support, which was modified by catalytic etching to create vacancy defects on the support. To enhance the effect of surface modification, the etched h-BN flakes were exfoliated by ultrasonication treatment and were further modified by controlling the pH of the surface. As a consequence of surface modification, the specific surface area increased from 41.89 to 67.29 m 2 /g. Microscopic analysis revealed that the size of the catalytic particles was mainly distributed with an average of 5 nm in modified h-BN. Surprisingly, the conversion efficiency of NO x gas approached 97% at a relatively low temperature (175−225 °C) when surface-modified h-BN was used as the support. The noticeable improvement in the catalytic performance is attributed to the high dispersion of active materials with the use of a porous support.

2D Boron Nitride Heterostructures: Recent Advances and Future Challenges

“…In addition to photocatalysis, which is the most studied application by far, h‐BN nanocomposites as electrocatalysts have also been designed. [ 91–95 ] Patil et al have reported a method to prepare an h‐BN‐manganese oxide (MnO x ) composite by adding h‐BN during the reducing process of potassium permanganate (KMnO 4 ). [ 91 ] h‐BN supports the growth of MnO x nanorods due to the seeding role played by the h‐BN surface.…”

“…Another example is the h‐BN/MnCe hetero‐catalyst for selective catalytic reduction (SCR) technology. [ 92 ] Aggregation of the catalyst, which reduces the conversion of nitrogen oxides into nontoxic gases, is the main drawback in SCR. A dispersion of the catalyst on proper support is a possible solution, and h‐BN has been tested as a potential candidate.…”

“…The etched h‐BN improves the dispersion of the catalyst and acts as a catalytically active site, thereby enhancing the SCR performance. [ 92 ]…”

Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources

“…In addition, a study was conducted using hexagonal boron nitride, which has a high melting point of 3000 °C and excellent thermal stability, as a support synthesized h-BN with a porous structure on the surface due to catalytic etching by the transition metal. When the active material is dispersed in this porous structure, the phase is thermally stabilized with high dispersibility, and phase changes and agglomeration are suppressed [ 97 ]. As a result, it was possible to nano-disperse the catalytically active material down to 10 nm by utilizing the surface defect anchoring sites.…”

High-Dispersed V2O5-CuOX Nanoparticles on h-BN in NH3-SCR and NH3-SCO Performance

“…Notably, h-BN can be synthesized in the shape of a plate owing to its structural properties, and it promotes the dispersion of catalytic species [ 34 ]. In addition, it is considered as a potential material in many research fields owing to its excellent properties, such as high thermal stability and conductivity originating from stable bonding and outstanding chemical stability [ 35 ]. These advantages render it suitable for long-term operation under high temperatures during NH 3 -SCR, which also involves toxic atmospheres.…”