Plasma-assisted manipulation of vanadia nanoclusters for efficient selective catalytic reduction of NOx

Abstract

Supported nanoclusters (SNCs) with distinct geometric and electronic structures have garnered significant attention in the field of heterogeneous catalysis. However, their directed synthesis remains a challenge due to limited efficient approaches. This study presents a plasma-assisted treatment strategy to achieve supported metal oxide nanoclusters from a rapid transformation of monomeric dispersed metal oxides. As a case study, oligomeric vanadia-dominated surface sites were derived from the classic supported V₂O₅-WO₃/TiO₂ (VWT) catalyst and showed nearly an order of magnitude increase in turnover frequency (TOF) value via an H₂-plasma treatment for selective catalytic reduction of NO with NH₃. Such oligomeric surface VO_x sites were not only successfully observed and firstly distinguished from WO_x and TiO₂ by advanced electron microscopy, but also facilitated the generation of surface amide and nitrates intermediates that enable barrier-less steps in the SCR reaction as observed by modulation excitation spectroscopy technologies and predicted DFT calculations.

Achieving supported nanoclusters with unique geometric and electronic structures continues to pose a challenge. Here, the authors introduce a plasma-assisted treatment approach for generating supported metal oxide nanoclusters, facilitated by the rapid transformation of monomeric dispersed metal oxides.