Disclosed herein are compositions having a mixed oxide core comprising cerium oxide and zirconium oxide, which is free of alumina. The mixed oxide core contains about 15 wt % to about 60 wt % cerium oxide and about 40 wt % to about 85 wt % zirconium oxide based on the total weight of the mixed oxide core. The mixed oxide core has a rare earth oxide coating, the rare earth being selected from the group consisting of cerium, lanthanum, neodymium, praseodymium, yttrium, and mixtures thereof. Further, precious metals, including palladium or rhodium, are dispersed on the surface of these composition and the compositions have higher rhodium or palladium dispersion versus a composition comprising a mixed oxide core without a rare earth oxide coating. Further disclosed are processes of producing these compositions. The compositions may be used as part of a catalyst system.

Disclosed herein are compositions having a mixed oxide core comprising cerium oxide and zirconium oxide, which is free of alumina. The mixed oxide core contains about 15 wt % to about 60 wt % cerium oxide and about 40 wt % to about 85 wt % zirconium oxide based on the total weight of the mixed oxide core. The mixed oxide core has a rare earth oxide coating, the rare earth being selected from the group consisting of cerium, lanthanum, neodymium, praseodymium, yttrium, and mixtures thereof. Further, precious metals, including palladium or rhodium, are dispersed on the surface of these composition and the compositions have higher rhodium or palladium dispersion versus a composition comprising a mixed oxide core without a rare earth oxide coating. Further disclosed are processes of producing these compositions. The compositions may be used as part of a catalyst system.

A catalyst for hydrorefining crude terephthalic acid, as well as its preparation method and application are provided. The catalyst includes a support and active components. The active components contains palladium and ruthenium in a weight ratio of (3-10):1, on element basis. The palladium is Pd.sup.0, and ruthenium includes Ru.sup.0 and Ru.sup.4+. Ru.sup.4+ and Ru.sup.0 are in a weight ratio of 0.1-1.0. The catalyst may be particularly suitable for hydrorefining crude terephthalic acid.

A catalyst for hydrorefining crude terephthalic acid, as well as its preparation method and application are provided. The catalyst includes a support and active components. The active components contains palladium and ruthenium in a weight ratio of (3-10):1, on element basis. The palladium is Pd.sup.0, and ruthenium includes Ru.sup.0 and Ru.sup.4+. Ru.sup.4+ and Ru.sup.0 are in a weight ratio of 0.1-1.0. The catalyst may be particularly suitable for hydrorefining crude terephthalic acid.

Disclosed are a catalyst for synergistic removal of nitrogen oxides (NO.sub.x) and CO as well as a preparation method and use thereof. The preparation method comprises: performing vibratory ball milling, washing, drying and calcining on aluminum isopropoxide and/or titanium isopropoxide, chlorides of five or more different metal elements and P123 and/or polyethylene glycol (PEG), stirring the obtained high-entropy oxide inner core and a gel of H.sub.3PO.sub.4 and Ce(NO.sub.3).sub.3, and then performing vibratory ball milling, washing, drying and calcining to obtain an high-entropy oxide loaded with CePO.sub.4 seeds; and preparing, by using ammonia water, a clear solution containing pyrophosphate and Ce(NO.sub.3).sub.3 in equal stoichiometric ratios, then adding the high-entropy oxide loaded with the CePO.sub.4 seeds and urea and/or tetrapropylammonium hydroxide (TPAH) to form a slurry, and, after hydrothermal reaction, washing, drying and calcining a solid to obtain the catalyst.

Disclosed are a catalyst for synergistic removal of nitrogen oxides (NO.sub.x) and CO as well as a preparation method and use thereof. The preparation method comprises: performing vibratory ball milling, washing, drying and calcining on aluminum isopropoxide and/or titanium isopropoxide, chlorides of five or more different metal elements and P123 and/or polyethylene glycol (PEG), stirring the obtained high-entropy oxide inner core and a gel of H.sub.3PO.sub.4 and Ce(NO.sub.3).sub.3, and then performing vibratory ball milling, washing, drying and calcining to obtain an high-entropy oxide loaded with CePO.sub.4 seeds; and preparing, by using ammonia water, a clear solution containing pyrophosphate and Ce(NO.sub.3).sub.3 in equal stoichiometric ratios, then adding the high-entropy oxide loaded with the CePO.sub.4 seeds and urea and/or tetrapropylammonium hydroxide (TPAH) to form a slurry, and, after hydrothermal reaction, washing, drying and calcining a solid to obtain the catalyst.