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Highly dispersed catalysts are widely used in industry and academia because of their large surface active sites. However, the predominant short‐range ordered structures in catalysts cannot be revealed by bulk characterization tools. The present study chooses a highly dispersed Fe−SiO2 FTS catalyst as a research object and shows how X‐ray absorption fine structure (XAFS) helps to analyze the chemical information (iron composition, reduction degree, and iron valence) and structural information (coordinating atom and coordination number) of catalyst. The activation process of catalysts are detailedly studied under different atmospheres (CO, H2, or 2H2/CO) by using both ex‐situ and in‐situ XAFS. CO activation behaves most effective during the whole process and finally produces the highest content of active iron species compared with H2 and 2H2/CO activation. The coordination number evolution of nearest Fe−O and Fe−C shells around Fe are put forward to understand the activation process. The present study demonstrates how XAFS elaborately reveals the phase transformations of the highly dispersed Fe−SiO2 FTS catalyst. [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]

The Cover shows a novel Cu‐SAPO‐44 zeolite which would be a promising candidate as a selective catalytic reduction (SCR) catalyst for deNOx with great potential in after‐treatment systems for mobile sources.In their Full Paper, Y. Xin et al. report for the first time, insights into the performance and active sites of this novel Cu ion‐exchanged SAPO‐44 zeolite (Cu‐SAPO‐44) in NH3‐SCR. Experimentally derived results demonstrate that Cu‐SAPO‐44 exhibits excellent activity and N2 selectivity over a wide temperature window even after severe hydrothermal aging and that two kinds of isolated Cu2+ species with high thermostability are the active sites. This findings represent a new opportunity for potential industrial applications of Cu‐SAPO‐44 and provide a choice for NOx control in diesel exhausts. More information can be found in the Full Paper by Y. Xin et al. on page 3740 in Issue 24, 2016 (DOI: 10.1002/cctc.201601159). [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]