摘要
Hydrocarbons(HCs)exert toxic effects on the activity of Cu-based zeolite catalysts for NH3-SCR on d...展开更多
Hydrocarbons(HCs)exert toxic effects on the activity of Cu-based zeolite catalysts for NH3-SCR on diesel vehicles.This study inve stigated the hydrocarbon resistance of both fresh and hydrothermally aged high-silica Cu-SSZ-16 catalysts.It was found that low-temperature activity of Cu-SSZ-16 catalyst decreased after C3H6 poisoning,which was mainly due to the blockage of pore channels and the coverage of Cu active sites as well as acid sites by the formation of carbon deposits.Additionally,[Cu(OH)]+-Z was proposed to be more easily affected by C3H6 poisoning than Cu2+-2Z.Hydrothermally aged Cu-SSZ-16 presented better C3H6 resistance than the fresh catalyst since less carbon deposits were accumulated and[Cu(OH)]+-Z species were partially transformed to more-stable Cu2+-2Z in the aged sample.This was probably because of the reduction of acid sites and the formation of CuOx,which enhanced the oxidation of C3H6,thereby inhibiting the formation of carbon deposits.In addition,the coverage of the active Cu species also influenced the adsorption and oxidation of NO,causing a decrease in low-temperature activity.Thus,the low-temperature activity could be fully recovered by hydrothermal treatment at 500℃due to the removal of carbon deposits and recovery of Cu active sites as well as acid sites.In summary,high-silica CuSSZ-16,with high resistance to HCs and excellent hydrothermal stability,is a competitive candidate as a catalyst for the NH3-SCR reaction in practical application.收起
基金
supported by the National Natural Science Foundation of China(Nos.52225004,22402220,and 52200136)
the National Key R&D Program of China(Nos.2022YFC3704400 and 2022YFC3701804)
the Construction Project of National New Material Production and Application Demonstration Platform(No.TC220H06N)。