Catalyst containing natural nanosilica, palladium(II) and copper(II) salts in oxidation of carbon monoxide with oxygen

The paper presents original results regarding the effect of long-term treatment of phlogopite concentrate with nitric acid on the phase ratio, chemical composition and catalytic activity of copper–palladium complexes in the reaction of carbon monoxide oxidation with air oxygen. Phlogopite concentrate is polyphasic and contains phases of phlogopite, clinochlore, diopside and tremolite. Samples were modified with 8M HNO3 at room temperature for 1; 24; 48; 72 h (8H-Phl-τ). Samples of 8H-Phl-τ (S -) and Pd(II)–Cu(II)/S - catalysts were characterized by XRD, SEM, FT-IR spectroscopy and pH metric methods. It is shown that the content of the phlogopite phase decreases in a number of these samples, while the content of the clinochlore phase increases. The content of diopside and tremolite phases varies irregularly and remains within the limits for the original sample. Long-term acid modification (72 h) leads to amorphization of the sample and the formation of nanosilica: the silicon content increases to 92 wt. %. The Wacker-type catalyst fixed on nanosilica showed a high degree (97%) of carbon monoxide conversion. © 2023, King Abdulaziz City for Science and Technology.