The present invention disclosed preparation method of a visible-light-driven CC@SnS.sub.2/SnO.sub.2 composite catalyst, and application thereof, comprising the following steps: preparing CC@SnS.sub.2 composite material in a solvent by using SnCl.sub.4.5H.sub.2O and C.sub.2H.sub.5NS as raw materials and carbon fiber cloth as a supporting material; calcining said CC@SnS.sub.2 composite material to obtain the visible-light-driven CC@SnS.sub.2/SnO.sub.2 composite catalyst. The present invention overcomes defects of the traditional methods of treating chromium-containing wastewater, including chemical precipitation, adsorption, ion exchange resin and electrolysis, and the photocatalytic technology can make full use of solar light source or artificial light source without adding adsorbent or reducing agent. In this case, the use of semiconductor photocatalyst to convert hexavalent chromium in chromium wastewater into less toxic and easily precipitated trivalent chromium greatly reduces the cost and energy consumption.

A method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including: a raw material preparation step including sub-step (I) of preparing an aqueous mixed liquid (A) containing Mo, V, and Sb, sub-step (II) of adding hydrogen peroxide to the aqueous mixed liquid (A), thereby facilitating oxidation of the aqueous mixed liquid (A) and obtaining an aqueous mixed liquid (A), and sub-step (III) of mixing the aqueous mixed liquid (A) and a Nb raw material liquid (B), thereby obtaining an aqueous mixed liquid (C); a drying step of drying the aqueous mixed liquid (C), thereby obtaining a dried powder; and a calcination step of calcining the dried powder under an inert gas atmosphere, wherein a time elapsed from addition of the hydrogen peroxide to the aqueous mixed liquid (A) to mixing the Nb raw material liquid (B) therewith is less than 5 minutes and the aqueous mixed liquid (A) before being subjected to the sub-step (III) has an oxidation-reduction potential of 150 to 350 mV.

A method for producing an oxide catalyst containing Mo, V, Sb, and Nb, the method including: a raw material preparation step including sub-step (I) of preparing an aqueous mixed liquid (A) containing Mo, V, and Sb, sub-step (II) of adding hydrogen peroxide to the aqueous mixed liquid (A), thereby facilitating oxidation of the aqueous mixed liquid (A) and obtaining an aqueous mixed liquid (A), and sub-step (III) of mixing the aqueous mixed liquid (A) and a Nb raw material liquid (B), thereby obtaining an aqueous mixed liquid (C); a drying step of drying the aqueous mixed liquid (C), thereby obtaining a dried powder; and a calcination step of calcining the dried powder under an inert gas atmosphere, wherein a time elapsed from addition of the hydrogen peroxide to the aqueous mixed liquid (A) to mixing the Nb raw material liquid (B) therewith is less than 5 minutes and the aqueous mixed liquid (A) before being subjected to the sub-step (III) has an oxidation-reduction potential of 150 to 350 mV.

[Mn.sub.3SrO.sub.4] cluster compounds are synthesized in a single step from raw materials consisting of simple and inexpensive Mn.sup.2+, Sr.sup.2+ inorganic compounds and carboxylic acids by using permanganate anion as oxidant. This step can be followed by the synthesis of asymmetric biomimetic water splitting catalyst [Mn.sub.4SrO.sub.4] cluster compounds in the presence of water. The [Mn.sub.4SrO.sub.4] cluster compound can catalyze the splitting of water in the presence of an oxidant to release oxygen gas. The neutral [Mn.sub.3SrO.sub.4](R.sub.1CO.sub.2)6(R.sub.1CO.sub.2H).sub.3 cluster compound can serve as precursors for the synthesis of biomimetic water splitting catalysts, and can be utilized in the synthesis of different types of biomimetic water splitting catalysts. [Mn.sub.4SrO.sub.4](R.sub.1CO.sub.2).sub.8(L.sub.1)(L.sub.2)(L.sub.3)(L.sub.4) cluster compounds can serve as artificial water splitting catalysts, can be utilized on the surface of an electrode or in the catalyzed splitting of water driven by an anoxidant.

[Mn.sub.3SrO.sub.4] cluster compounds are synthesized in a single step from raw materials consisting of simple and inexpensive Mn.sup.2+, Sr.sup.2+ inorganic compounds and carboxylic acids by using permanganate anion as oxidant. This step can be followed by the synthesis of asymmetric biomimetic water splitting catalyst [Mn.sub.4SrO.sub.4] cluster compounds in the presence of water. The [Mn.sub.4SrO.sub.4] cluster compound can catalyze the splitting of water in the presence of an oxidant to release oxygen gas. The neutral [Mn.sub.3SrO.sub.4](R.sub.1CO.sub.2)6(R.sub.1CO.sub.2H).sub.3 cluster compound can serve as precursors for the synthesis of biomimetic water splitting catalysts, and can be utilized in the synthesis of different types of biomimetic water splitting catalysts. [Mn.sub.4SrO.sub.4](R.sub.1CO.sub.2).sub.8(L.sub.1)(L.sub.2)(L.sub.3)(L.sub.4) cluster compounds can serve as artificial water splitting catalysts, can be utilized on the surface of an electrode or in the catalyzed splitting of water driven by an anoxidant.

Oxidative dehydrogenation catalysts comprising MoVNbTeO having improved consistency of composition and a 25% conversion of ethylene at less than 420 C. and a selectivity to ethylene above 95% are prepared by treating the catalyst precursor with H.sub.2O.sub.2 in an amount equivalent to 0.30-2.8 mL H.sub.2O.sub.2 of a 30% solution per gram of catalyst precursor prior to calcining.

Oxidative dehydrogenation catalysts comprising MoVNbTeO having improved consistency of composition and a 25% conversion of ethylene at less than 420 C. and a selectivity to ethylene above 95% are prepared by treating the catalyst precursor with H.sub.2O.sub.2 in an amount equivalent to 0.30-2.8 mL H.sub.2O.sub.2 of a 30% solution per gram of catalyst precursor prior to calcining.

The present invention relates to a catalyst comprising at least one oxide of vanadium, at least one oxide of tungsten, at least one oxide of cerium, at least one oxide of titanium and at least one oxide of antimony, and an exhaust system containing said oxides.

The present invention is directed to a nanostructured binary oxide TiO.sub.2Al.sub.2O.sub.3 with high acidity and its synthesis process via the sol-gel method, hydrotreating and thermal activation. The nanostructured binary oxide TiO.sub.2Al.sub.2O.sub.3 with high acidity consists basically of titanium oxide and aluminum oxide with the special characteristic of being obtained as nanostructures, in their nanocrystal-nanotube evolution, which provides special physicochemical properties such as high specific area, purity and phase stability, acidity stability and different types of active acid sites, in addition to the capacity to disperse and stabilize active metal particles with high activity and selectivity mainly in catalytic processes.

The present invention is directed to a nanostructured binary oxide TiO.sub.2Al.sub.2O.sub.3 with high acidity and its synthesis process via the sol-gel method, hydrotreating and thermal activation. The nanostructured binary oxide TiO.sub.2Al.sub.2O.sub.3 with high acidity consists basically of titanium oxide and aluminum oxide with the special characteristic of being obtained as nanostructures, in their nanocrystal-nanotube evolution, which provides special physicochemical properties such as high specific area, purity and phase stability, acidity stability and different types of active acid sites, in addition to the capacity to disperse and stabilize active metal particles with high activity and selectivity mainly in catalytic processes.