Catalysts for oxidative esterification can be used, for example, fro converting (meth)acrolein to methyl (meth)acrylate. The catalysts are especially notable for high mechanical and chemical stability even over very long time periods, including activity and/or selectivity relatively in continuous operation in media having even a small water content.

The invention relates to polyoxometalates represented by the formula (A.sub.n).sup.m+{M′.sub.s[M″M.sub.12X.sub.8O.sub.yR.sub.zH.sub.q]}.sup.m− or solvates thereof, corresponding supported polyoxometalates, and processes for their preparation, as well as corresponding metal-clusters, optionally in the form of a dispersion in a liquid carrier medium or immobilized on a solid support, and processes for their preparation, as well as their use in reductive conversion of organic substrate.

A catalyst comprising a noble metal disposed on a support. The noble metal is present in an amount ranging from 0.1 wt % to 10 wt % relative to the total weight of the catalyst. The support comprises at least 50 wt % silicon carbide relative to the total weight of the support. The silicon carbide has a surface area of at least 5 m.sup.2/g. A method for preparing methyl methacrylate from methacrolein and methanol using the catalyst is also disclosed.

To provide a photocatalyst decomposition apparatus that can supply a liquid phase containing a substance to be decomposed by a photocatalyst and that can perform decomposition of the substance more efficiently than in the related art. A photocatalyst decomposition system according to the invention includes: a gas phase generation apparatus configured to convert a liquid phase containing a decomposition object into a gas phase; and a photocatalyst member configured to come into contact with the gas phase to decompose the decomposition object by light from a light source. The photocatalyst member includes a base material formed of a porous material and a photocatalyst layer provided on a surface of the base material.

A method for producing diene comprises a step 1 of obtaining a straight chain internal olefin by removing a branched olefin from a raw material including at least the branched olefin and a straight chain olefin; and a step 2 of producing diene from the internal olefin by oxidative dehydrogenation using a first catalyst and a second catalyst, and the first catalyst has a complex oxide including bismuth, molybdenum and oxygen, and the second catalyst includes at least one selected from the group consisting of silica and alumina.

The invention relates to polyoxometalates represented by the formula (A.sub.n).sup.m+{M.sub.s[MM.sub.12X.sub.8O.sub.yR.sub.zH.sub.q]}.sup.m or solvates thereof, corresponding supported polyoxometalates, and processes for their preparation, as well as corresponding metal-clusters, optionally in the form of a dispersion in a liquid carrier medium or immobilized on a solid support, and processes for their preparation, as well as their use in reductive conversion of organic substrate.

Catalysts for oxidative esterification can be used, for example, for converting (meth)acrolein to methyl (meth)acrylate. The catalysts are especially notable for high mechanical and chemical stability even over very long time periods, including activity and/or selectivity relatively in continuous operation in media having even a small water content.

The disclosure relates to systems and methods to produce hydrogen (H.sub.2) gas from hydrogen sulfide (H.sub.2S). H.sub.2S is contacted with a catalyst to form H.sub.2 gas and sulfur adsorbed to the catalyst. The adsorbed sulfur is contacted with oxygen (O.sub.2) gas to convert the adsorbed sulfur to sulfur dioxide (SO.sub.2) and regenerate the catalyst

Provided is a catalyst for an oxygen reduction reaction, including an alloy in which two metals are mixed, in which the corresponding alloy is an alloy of iridium (Ir); and silicon (Si), phosphorus (P), germanium (Ge), or arsenic (As). The corresponding catalyst for the oxygen reduction reaction may have excellent price competitiveness while exhibiting a catalytic activity which is equal to or similar to that of an existing Pt catalyst. Accordingly, when the catalyst is used, the amount of platinum catalyst having low price competitiveness may be reduced, so that a production unit cost of a system to which the corresponding catalyst is applied may be lowered.

Provided is a catalyst for an oxygen reduction reaction, including an alloy in which two metals are mixed, in which the corresponding alloy is an alloy of iridium (Ir); and silicon (Si), phosphorus (P), germanium (Ge), or arsenic (As). The corresponding catalyst for the oxygen reduction reaction may have excellent price competitiveness while exhibiting a catalytic activity which is equal to or similar to that of an existing Pt catalyst. Accordingly, when the catalyst is used, the amount of platinum catalyst having low price competitiveness may be reduced, so that a production unit cost of a system to which the corresponding catalyst is applied may be lowered.