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Abstract: Dimethyl ether steam reforming (DME SR) is a promising route to provide H2 for on‐board H2‐based fuel cells. Herein, we synthesized the La2O3‐modified Cu/SiO2 catalyst with dual copper species of Cu0 and Cu+ for DME SR, which exhibits both the high catalytic performance and long‐term stability. The strong electron donor‐acceptor interaction between the lanthanum and copper species occurs after reduction of the catalysts, which is an essential factor to quantitatively determine the ratio of Cu+/(Cu0+Cu+). The addition of La can improve the dispersion of both metallic Cu and Cu2O on the catalysts, as well. After modulating the ratio of Cu+/(Cu0+Cu+) to ∼0.5 by varying the La loading, we achieved the highest activity and lowest CO selectivity. After the durability tests, the results of TEM, EXAFS, and XPS reveal that the addition of La on the Cu/SiO2 catalysts not only stabilizes the copper species from aggregation, especially for the metallic Cu, but also avoids over‐reduction of the Cu+ species to Cu0. The constant ratio of Cu+/(Cu0+Cu+) on the La‐modified Cu/SiO2 catalyst ensures the high catalytic stability in DME SR. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NO x) contribute much to acid rain, photochemical smog, and the depletion of tropospheric ozone. A novel, small-pore Cu-exchanged chabazite (Cu-CHA) zeolite, Cu-SAPO-44, was first studied for the selective catalytic reduction of NO x with ammonia (NH3-SCR), and exhibits excellent activity and N2 selectivity over the wide temperature window from 200-550 °C. The Cu content in Cu-SAPO-44 plays a significant role in the NH3-SCR reactions. Two kinds of isolated Cu2+ species inside the large cages and in the six-membered rings of the CHA structure were verified as the active sites, which are responsible for the low-temperature and high-temperature activity, respectively. Cu-SAPO-44 is shown to be a promising candidate as a SCR catalyst for deNO x with great potential in after-treatment systems for either mobile or stationary sources. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NO x) contribute much to acid rain, photochemical smog, and the depletion of tropospheric ozone. A novel, small-pore Cu-exchanged chabazite (Cu-CHA) zeolite, Cu-SAPO-44, was first studied for the selective catalytic reduction of NO x with ammonia (NH3-SCR), and exhibits excellent activity and N2 selectivity over the wide temperature window from 200-550 °C. The Cu content in Cu-SAPO-44 plays a significant role in the NH3-SCR reactions. Two kinds of isolated Cu2+ species inside the large cages and in the six-membered rings of the CHA structure were verified as the active sites, which are responsible for the low-temperature and high-temperature activity, respectively. Cu-SAPO-44 is shown to be a promising candidate as a SCR catalyst for deNO x with great potential in after-treatment systems for either mobile or stationary sources. [ABSTRACT FROM AUTHOR]