The preferential oxidation of CO in excess hydrogen: A study of the influence of KOH/K2CO3 on CuO–CeO2−x catalysts

Effects of precipitants on the catalytic performance of Cu/CeO2 catalysts for the water–gas shift reaction

The ratio of the precipitant (K2CO3 : KOH) was confirmed to affect the Cu dispersion and OSC of the Cu/CeO2 catalyst, and the Cu/CeO2 catalyst prepared with the K2CO3 : KOH ratio of 3 : 1 showed the highest activity.

Investigation of the re-dispersion of matrix Cu species in CuxCe1−xO2 nanorod catalysts and its effect on the catalytic performance in CO-PROX

The CO-PROX catalytic performance is sensitive to the re-dispersion state of matrix copper species, which separate out as highly dispersed CuO_x under thermal treatment.

Influence of pH on the catalytic performance of CuO–CoOx–CeO2 for CO oxidation

Ternary catalysts, namely CuO–CoO_x–CeO₂, are prepared by coprecipitation with different pH and characterized by techniques such as N₂ adsorption/desorption, XRD, TPR, TEM and XPS.

(39)K NMR of solid potassium salts at 21 T: effect of quadrupolar and chemical shift tensors

39K Solid State NMR spectra (static and magic angle spinning (MAS)) on a set of potassium salts measured at 21.14 T show that the chemical shift range for K(+) ions in diamagnetic salts is well in excess of 100 ppm contrary to previous assumptions that it was quite small. Inequivalent potassium sites in crystals can be resolved through differences in chemical shifts, with chemically similar sites showing differences of over 10 ppm. The quadrupolar coupling constants obtained from MAS and solid echo experiments on powders cover the range from zero for potassium in cubic environments in halides to over 3 MHz for the highly asymmetric sites in K2CO3. Although the quadrupolar effects generally dominate the 39K spectra, in several instances, we have observed subtle but significant contributions of chemical shift anisotropy with values up to 45 ppm, a first such observation. Careful analysis of static and MAS spectra allows the observation of the various chemical shift and quadrupole coupling tensor components as well as their relative orientations, thereby demonstrating that high-field 39K NMR spectroscopy in the solid state has a substantial sensitivity to the local environment with parameters that will be of considerable value in materials characterization and electronic structure studies.