A honeycomb structure including an electrically conductive honeycomb structure portion, comprising an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells forming flow paths from one end surface to the other end surface; and a pair of electrode layers provided on an outer surface of the outer peripheral wall so as to face each other across a central axis of the honeycomb structure portion; wherein a coefficient of linear expansion of the honeycomb structure portion measured according to JIS R1618:2002 when temperature is changed from 40° C. to 300 ° C. is 4.1×10.sup.−6/° C. or more, and the coefficient of linear expansion of the honeycomb structure portion measured according to JIS R1618:2002 when the temperature is changed from 300 ° C. to 800 ° C. is 4.2×10.sup.−6/° C. or more and 4.8×10.sup.−6/° C. or less.

A honeycomb structure including an electrically conductive honeycomb structure portion, comprising an outer peripheral wall, and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells forming flow paths from one end surface to the other end surface; and a pair of electrode layers provided on an outer surface of the outer peripheral wall so as to face each other across a central axis of the honeycomb structure portion; wherein a coefficient of linear expansion of the honeycomb structure portion measured according to JIS R1618:2002 when temperature is changed from 40° C. to 300 ° C. is 4.1×10.sup.−6/° C. or more, and the coefficient of linear expansion of the honeycomb structure portion measured according to JIS R1618:2002 when the temperature is changed from 300 ° C. to 800 ° C. is 4.2×10.sup.−6/° C. or more and 4.8×10.sup.−6/° C. or less.

A honeycomb structure including a honeycomb structure portion made of ceramics having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells; and a pair of electrode layers provided on an outer surface of the outer peripheral wall; wherein in a cross-section orthogonal to a direction in which the cells extend, assuming a coordinate value of a center of gravity O is 0, and a coordinate value of an inner peripheral surface of the outer peripheral wall is 1.00 R, an average value P.sub.1A of a porosity (%) of the partition walls in a range of coordinate values of 0 to 0.50 R and an average value P.sub.2A of a porosity (%) of the partition walls in a range of coordinate values of 0.50 R to 1.00 R satisfy a relationship of 1<P.sub.2A/P.sub.1A.

A honeycomb structure including a honeycomb structure portion made of ceramics having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and partitioning a plurality of cells; and a pair of electrode layers provided on an outer surface of the outer peripheral wall; wherein in a cross-section orthogonal to a direction in which the cells extend, assuming a coordinate value of a center of gravity O is 0, and a coordinate value of an inner peripheral surface of the outer peripheral wall is 1.00 R, an average value P.sub.1A of a porosity (%) of the partition walls in a range of coordinate values of 0 to 0.50 R and an average value P.sub.2A of a porosity (%) of the partition walls in a range of coordinate values of 0.50 R to 1.00 R satisfy a relationship of 1<P.sub.2A/P.sub.1A.

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

A catalyst support comprising at least 95% silicon carbide, having surface areas of ≤10 m.sup.2/g and pore volumes of ≤1 cc/g. A method of producing a catalyst support, the method including mixing SiC particles of 0.1-20 microns, SiO.sub.2 and carbonaceous materials to form an extrusion, under inert atmospheres, heating the extrusion at temperatures of greater than 1400° C., and removing residual carbon from the heated support under temperatures below 1000° C. A catalyst on a carrier, comprising a carrier support having at least about 95% SiC, with a silver solution impregnated thereon comprising silver oxide, ethylenediamine, oxalic acid, monoethanolamine and cesium hydroxide. A process for oxidation reactions (e.g., for the production of ethylene oxide, or oxidation reactions using propane or methane), or for endothermic reactions (e.g., dehydrogenation of paraffins, of ethyl benzene, or cracking and hydrocracking hydrocarbons).

The present disclosure refers to systems, methods, and catalysts for conversion of a hydrocarbon to hydrogen. The catalyst typically comprises a matrix comprising fused silica, quartz, glass, a zeolite, Si.sub.3N.sub.4, SiC, SiC.sub.xO.sub.y wherein 4x+2y =4, SiO.sub.aN.sub.b wherein 2a+3b =4, BN, TiO.sub.2, ZrO.sub.2, Al.sub.2O.sub.3, CeO.sub.2, Nb.sub.2O.sub.5, La.sub.2O.sub.3, a perovskite, or any mixture thereof. A metal dopant is embedded in the matrix. The metal dopant comprises Fe, Ni, Co, Cu, Zn, Mn, or any mixture thereof.

The present disclosure refers to systems, methods, and catalysts for conversion of a hydrocarbon to hydrogen. The catalyst typically comprises a matrix comprising fused silica, quartz, glass, a zeolite, Si.sub.3N.sub.4, SiC, SiC.sub.xO.sub.y wherein 4x+2y =4, SiO.sub.aN.sub.b wherein 2a+3b =4, BN, TiO.sub.2, ZrO.sub.2, Al.sub.2O.sub.3, CeO.sub.2, Nb.sub.2O.sub.5, La.sub.2O.sub.3, a perovskite, or any mixture thereof. A metal dopant is embedded in the matrix. The metal dopant comprises Fe, Ni, Co, Cu, Zn, Mn, or any mixture thereof.

A honeycomb structure 20 according to the present invention includes: a ceramic honeycomb structure portion 10 including: an outer peripheral wall 12; a partition wall 13, the partition wall 13 defining a plurality of cells 16; and a pair of electrode layers 14a, 14b each arranged so as to extend in a form of a band on an outer surface of the outer peripheral wall 12, across a central axis of the honeycomb structure portion 10, wherein the honeycomb structure portion 10 is provided in an end portion region(s) extending in a direction from the one end face and/or the other end face to a center in a flow path length direction of the honeycomb structure portion 10, and the honeycomb structure portion 10 comprises at least one low porosity portion 4 having a lower porosity than an average porosity of the whole honeycomb structure portion 10.

A honeycomb structure 20 according to the present invention includes: a ceramic honeycomb structure portion 10 including: an outer peripheral wall 12; a partition wall 13, the partition wall 13 defining a plurality of cells 16; and a pair of electrode layers 14a, 14b each arranged so as to extend in a form of a band on an outer surface of the outer peripheral wall 12, across a central axis of the honeycomb structure portion 10, wherein the honeycomb structure portion 10 is provided in an end portion region(s) extending in a direction from the one end face and/or the other end face to a center in a flow path length direction of the honeycomb structure portion 10, and the honeycomb structure portion 10 comprises at least one low porosity portion 4 having a lower porosity than an average porosity of the whole honeycomb structure portion 10.