Tailoring the simultaneous abatement of methanol and NO_(x) on Sb-Ce-Zr catalysts via copper modification

摘要

Simultaneously removal of NO_(x)and VOCs over NH3-SCR catalysts have attracted lots of attention recently.However,the presence of VOCs would have negative effect on deNOx efficiency especially at low temperature.In this study,copper modification onto Sb_(0.5)CeZr_(2)O_(x)(SCZ)catalyst were performed to enhance the catalytic performance for simultaneous control of NNO_(x)and methanol.It was obtained that copper addition could improve the low-temperature activity of both NOx conversion and methanol oxidation,where the optimal catalyst(Cu_(0.05)SCZ)exhibited a deNOx activity of 96%and a mineralization rate of 97%at 250℃,which are around 10%higher than that of Cu free sample.The characterization results showed that copper addition could obviously enhance the redox capacity of the catalysts.As such,the inhibition effect of methanol incomplete oxidation on NO adsorption and NH3 activation were then lessened and the conversion of surface formamide species were also accelerated,resulting in the rising of NOx conversion at low temperature.However,excessive copper addition would damage the Sb-Ce-Zr oxides solid solution structure owing to Cu-Ce strong interactions,decreasing the surface area and acidity.Meanwhile,due to easier over-oxidation of NH3 with more Cu addition,the temperature window for NOx conversion would become quite narrow.These findings could provide useful guidelines for the synergistic removal of VOCs over SCR catalyst in real application.