Pt-based catalysts can be poisoned
by the chlorine formed during
the oxidation of multicomponent volatile organic compounds (VOCs)
containing chlorinated VOCs. Improving the low-temperature chlorine
resistance of catalysts is important for industrial applications,
although it is yet challenging. We hereby demonstrate the essential
catalytic roles of a bifunctional catalyst with an atomic-scale metal/oxide
interface constructed by an intermetallic compound nanocrystal. Introducing
trichloroethylene (TCE) exhibits a less negative effect on the catalytic
activity of the bimetallic catalyst for o-xylene
oxidation, and the partial deactivation caused by TCE addition is
reversible, suggesting that the bimetallic, HCl-etched Pt3Sn(E)/CeO2 catalyst possesses much stronger chlorine resistance
than the conventional Pt/CeO2 catalyst. On the site-isolated
Pt–Sn catalyst, the presence of aromatic hydrocarbon significantly
inhibits the adsorption strength of TCE, resulting in excellent catalytic
stability in the oxidation of the VOC mixture. Furthermore, the large
amount of surface-adsorbed oxygen species generated on the electronegative
Pt is highly effective for low-temperature C–Cl bond dissociation.
The adjacent promoter (Sn–O) possesses the functionality of
acid sites to provide sufficient protons for HCl formation over the
bifunctional catalyst, which is considered critical to maintaining
the reactivity of Pt by removing Cl and decreasing the polychlorinated
byproducts.
Moiré fringe, originated from the beating of two sets of lattices, is a commonly observed phenomenon in physics, optics, and materials science. Recently, a new method of creating moiré fringe via scanning transmission electron microscopy (STEM) has been developed to image materials’ structures at a large field of view. Moreover, this method shows great advantages in studying atomic structures of beam sensitive materials by significantly reduced electron dose. Here, the development of the STEM moiré fringe (STEM‐MF) method is reviewed. The authors first introduce the theory of STEM‐MF and then discuss the advances of this technique in combination with geometric phase analysis, annular bright field imaging, energy dispersive X‐ray spectroscopy, and electron energy loss spectroscopy. Applications of STEM‐MF on strain, defects, 2D materials, and beam‐sensitive materials are further summarized. Finally, the authors′ perspectives on the future directions of STEM‐MF are presented.
Iridium (Ir) single-atom catalysts (SACs) exhibit the extraordinary advantage in oxygen evolution reaction (OER) owing to their unique electronic structure and maximized atom utilization. However, the further development meets the...
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