XPS Characterization and Bactericidal Properties of a Biomass Derived Silica-Copper Nanocomposite

Direct Stepwise Oxidation of Methane to Methanol over Cu–SiO2

“…At 650 °C, a small peak assigned to cristobalite phase was observed in line with the literature on Cu−SiO 2 treated at similar temperatures. 52,53 We hypothesize that the disappearance of CuO crystal peaks might be due a number of phenomena including the formation of dispersed Cu species, doping of Cu into the SiO 2 matrix due to partial crystallization of the support, or formation of amorphous islands. At 800 °C, peaks associated with (002) and (111) planes of CuO at 2θ angles of 35.4°and 38.7°, respectively were observed with a very small intensity, indicating that a small portion of copper formed CuO crystals.…”

Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions

“…While Chang et al argue that the stable Si–O–Cu bonds are primarily electrostatic, 48 Parameswaran et al suggest that their stable nature is covalent. 49 …”

“…Experimental synthesis of copper-containing silicates reveals a mixture of copper in each of its valence states. ,, X-ray photoelectron spectroscopy (XPS) reveals the presence of copper hydroxide, copper oxide, and Si–O–Cu bonds in these clusters. While Chang et al argue that the stable Si–O–Cu bonds are primarily electrostatic, Parameswaran et al suggest that their stable nature is covalent …”

“…While Chang et al argue that the stable Si−O−Cu bonds are primarily electrostatic, 48 Parameswaran et al suggest that their stable nature is covalent. 49 Our model reactant surface is a copper-containing silica-like structure derived from the addition of a −O−Cu−(OH) 2 moiety to the previously optimized tetrahedrally-coordinated, radical hydroxide cluster found by Kubicki et al 41 [Figures 3a (3-coordinate Cu) and 4a (vide inf ra tetrahedral Cu cluster)].…”