With in situ IR, two different CO adsorption bands were detected on various chemical state gold catalysts. One band is attributed to the linear CO on an oxidized gold catalyst(2100 cm -1 ), the other one is as...With in situ IR, two different CO adsorption bands were detected on various chemical state gold catalysts. One band is attributed to the linear CO on an oxidized gold catalyst(2100 cm -1 ), the other one is ascribed to the bridged CO on metallic gold (2085 cm -1 ). CO pulse reaction showed that Au/Fe 2O 3 catalyst had a room temperature activity even in the presence of moisture. The produced CO 2 was detained and more easily desorbed from supported gold catalyst than support oxide. TPD IDT results indicated that the O - 2 superoxide ions are the possible active oxygen species.展开更多
The catalytic oxidation of toluene over Ag/SBA‐15synthesized under different pretreatment conditions,including O2at500°C(denoted O500),H2at500°C(H500),and O2at500°C followed by H2at300°C(O500‐H30...The catalytic oxidation of toluene over Ag/SBA‐15synthesized under different pretreatment conditions,including O2at500°C(denoted O500),H2at500°C(H500),and O2at500°C followed by H2at300°C(O500‐H300)was studied.The pretreated samples were investigated by N2physisorption,X‐ray diffraction,and ultraviolet‐visible diffuse reflectance.The pretreatment atmosphere greatly influences the status of the Ag and O species,which in turn significantly impacts the adsorption and catalytic removal of toluene.Ag2O and amorphous Ag particles,as well as a large amount of subsurface oxygen species,are formed on O500,and the subsurface oxygen enhances the interaction between Ag species and toluene,so O500shows good activity at higher temperature.However,its activity at lower temperature is not as high as expected,with a reduced presence of Ag2O and lower adsorption capacity for toluene.H2pretreatment at500°C is conducive to the formation of large Ag particles and yields the largest adsorption capacity for toluene,so H500exhibits the best activity at lower temperatures;however,because of poor interaction between Ag and toluene,its activity at higher temperature is modest.The O500‐H300sample exhibits excellent catalytic activity during the whole reaction process,which can be attributed to the small and highly dispersed Ag nanoparticles as well as the existence of subsurface oxygen.展开更多
文摘With in situ IR, two different CO adsorption bands were detected on various chemical state gold catalysts. One band is attributed to the linear CO on an oxidized gold catalyst(2100 cm -1 ), the other one is ascribed to the bridged CO on metallic gold (2085 cm -1 ). CO pulse reaction showed that Au/Fe 2O 3 catalyst had a room temperature activity even in the presence of moisture. The produced CO 2 was detained and more easily desorbed from supported gold catalyst than support oxide. TPD IDT results indicated that the O - 2 superoxide ions are the possible active oxygen species.
基金supported by the National Natural Science Foundation of China(21377016,21577014)Program for Changjiang Scholars and Innovative Research Team in University(IRT_13R05)~~
文摘The catalytic oxidation of toluene over Ag/SBA‐15synthesized under different pretreatment conditions,including O2at500°C(denoted O500),H2at500°C(H500),and O2at500°C followed by H2at300°C(O500‐H300)was studied.The pretreated samples were investigated by N2physisorption,X‐ray diffraction,and ultraviolet‐visible diffuse reflectance.The pretreatment atmosphere greatly influences the status of the Ag and O species,which in turn significantly impacts the adsorption and catalytic removal of toluene.Ag2O and amorphous Ag particles,as well as a large amount of subsurface oxygen species,are formed on O500,and the subsurface oxygen enhances the interaction between Ag species and toluene,so O500shows good activity at higher temperature.However,its activity at lower temperature is not as high as expected,with a reduced presence of Ag2O and lower adsorption capacity for toluene.H2pretreatment at500°C is conducive to the formation of large Ag particles and yields the largest adsorption capacity for toluene,so H500exhibits the best activity at lower temperatures;however,because of poor interaction between Ag and toluene,its activity at higher temperature is modest.The O500‐H300sample exhibits excellent catalytic activity during the whole reaction process,which can be attributed to the small and highly dispersed Ag nanoparticles as well as the existence of subsurface oxygen.
