Three-dimensionally ordered macroporous(3DOM) structure promoted the activity and H_(2)O poisoning resistance of Ce Mn/3DOM-TiO_(2) catalyst in NH_(3)-SCR

NH_(3)-SCR is an effective mean of NOxremoval in the non-electric industry, however, the high activation temperature and poor H_(2)O resistance of SCR catalysts posed a barrier to its application. In this work, a series of three-dimensionally ordered macroporous(3DOM) catalysts were synthesized via a colloidal crystal template(CCT) method, and various characterizations were carried out to explore the physicochemical property of catalysts. The experiment results reveal that Ce_(0.2)Mn_(0.2)/3DOM-TiO_(2) catalyst presents the excellent low-temperature catalytic activity of nearly 100% at 100℃. Furthermore, the enhanced H_(2)O resistance is achieved, certified by the unaffected NO remove at 150℃ in the participation of 15 vol% H_(2)O. The characterizations results exhibit that the improved dispersion of the active component and enhanced redox ability are conducive to the low-temperature catalytic activity. N_(2) adsorption and desorption experiments indicate that catalyst with 3DOM support possesses a larger pore diameter and specific surface area, which may weaken the condensation of H_(2)O in the microporosity of catalysts and improved the H_(2)O resistance of the catalyst. In situ DRIFTS results manifest that Ce_(0.2)Mn_(0.2)/3DOM-TiO_(2) catalyst could not only absorb more NH_(3) and generate more surface-active sites, but inhibit the competitive adsorption between H_(2)O and SCR reactants.

Optimized Pt-MnO_(x) interface in Pt-MnO_(x)/3DOM-Al_(2)O_(3)catalysts for enhancing catalytic soot combustion

The catalysts of three-dimensionally ordered macroporous(3 DOM)Al_(2)O_(3)-supported core-shell structured Pt@MnOx nanoparticles(3 DOM-Pt@MnO_(x)/Al_(2)O_(3))were successfully prepared by the gas bubbling-assisted membrane reduction-precipitation(GBMR/P)method.Pt@MnO_(x)core-shell nanoparticles(NPs)are highly dispersed on the inner surface of 3 DOM-Al_(2)O_(3)support.Pt@MnOx/3 DOM-Al_(2)O_(3)catalysts,which combine both advantages of high-efficiency soot-catalyst contact by 3 DOM-Al_(2)O_(3)structure and the abundant active sites by the optimized Pt-MnO_(x)interface,exhibit high catalytic activities for soot combustion,and the catalytic activities are strongly dependent on the thickness of MnO_(x)shell.Among the catalysts,3 DOM-Pt@MnO_(x)/Al_(2)O_(3)-1 catalyst with optimized Pt-MnO_(x)interface shows the highest catalytic activity for soot combustion,i.e.,its values of T_(50)and S_(CO_(2))^(m) are 351℃and98.6%,respectively.The highest density of Pt-MnO_(x)active sites for adsorptio n-activation of gaseous O_(2)is responsible for enhancing catalytic activity for soot combustion.Pt@MnOx/3 DOM-Al_(2)O_(3)catalysts are promising to practical applications for the emission reduction of soot particles.