Mesoporous silica SBA-15 modified with copper as an efficient NO _2 adsorbent at ambient conditions

摘要

Copper oxide particles were synthesized by precipitation in sodium hydroxide and dispersed simultaneously in mesoporous SBA-15 silica. The materials were then submitted to thermal treatment under nitrogen at different temperatures. They were tested as novel NO _2 adsorbents in dynamic condition at room temperature. The surface of the initial and exhausted materials was characterized using N _2 adsorption, XRD, TEM, thermal analysis and FT-IR. The addition of Cu _2O particles leads to a significant increase in the NO _2 adsorption capacity. However, no trend between the NO _2 capacity and the temperature of the thermal treatment of the materials has been observed. The amount of NO released during the NO _2 adsorption was found to be lower on the materials submitted to a low temperature treatment. On these materials, the formation of copper nitrites is favored, whereas on materials treated at higher temperature, copper nitrates are formed as a predominant species. The results suggest that silanol groups of the silica matrix play an important role in NO _2 adsorption and NO retention at room temperature.