Highly stable and Active Cu1 /CeO2 Single-Atom Catalyst for CO Oxidation: A DFT Study.

We carried out density functional theory simulations to examine the stability and CO oxidation activity of single Cu atoms supported on CeO2 (111). Both the strong binding energy and high activation energy for Cu single atom diffusion indicate a high stability of the Cu1 /CeO2 single-atom catalyst. Electronic structure analysis verifies the formation of Cu+ cation due to electron transfer. The frequency analysis further corroborates that the experimentally observed IR bands around 2114-2130 cm-1 of CO adsorption at the boundary of Cu/CeO2 correspond to Cu+ -carbonyl species. Cu1 /CeO2 single-atom catalyst displays a promising catalytic activity for CO oxidation via Mars van Krevelen mechanism.

Preparation of Fe-MOFs by microwave-assisted ball milling for reducing Cr(vi) in wastewater.

Fe-Based metal-organic frameworks (Fe-MOFs) were prepared with trimesic acid and FeSO4·7H2O via a microwave-assisted ball milling approach. The structure and thermal stability of the as-prepared Fe-MOFs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). When used to degrade 20 mg L-1 hexavalent chromium in aqueous solution, the Fe-MOFs were found to completely reduce a 100 mL solution within 120 min under natural light and a 400 mL solution within 90 min under Xe lamp irradiation. Under natural sunlight, 98% of the Cr(vi) was removed from a 40 mL solution after 40 min.