Abstract: A nitrate reduction method includes the step of reducing at least one type selected from a group of nitrates and nitrites at an active site included in a defect of graphene in a reduction reaction, wherein the graphene is a reduced product of graphene oxide, and the defect of the graphene is derived from a defect of the graphene oxide.

Abstract: An electrically conductive hybrid material includes: a covalent organic framework having pores; and a conductor material, wherein the covalent organic framework is supported on the conductor material. The covalent organic framework that does not have electron conductivity is supported on the conductor material such as a carbon material, thereby can be given the electron conductivity, and becomes usable as such a catalyst material and such an electrode material, which involve the electron transfer, these materials including an electrode catalyst material of a fuel cell, and the like.

Abstract: A carbon-based material in accordance with the present invention includes graphene doped with metal atoms and at least one type of non-metal atoms selected from a group consisting of nitrogen atoms, boron atoms, sulfur atoms, and phosphorus atoms. A diffraction pattern obtained by X-ray diffraction measurement of the carbon-based material by use of CuK? radiation showing that a proportion of the highest of intensities of peaks derived from an inactive metal compound and a metal crystal to an intensity of a (002) peak is 0.1 or less.

Abstract: A nitrate reduction method in accordance with the present invention reduces at least one type of nitrates and nitrites in a presence of a carbon-based material containing at least one selected from a group consisting of graphite, graphene, and amorphous carbon.

Abstract: A divalent copper salt and/or trivalent iron salt is supported on a surface of a metal ion-doped titanium oxide obtained by doping titanium oxide with metal ions to give a metal ion-doped titanium oxide with a valence band potential of 3 V or more (vs. SHE, pH=0) and a bandgap of 3 V or less between the valence band and an energy level of electrons excited from the valence band (including conduction band minimum potential and isolated potential). The metal ion-doped titanium oxide can be made to exhibit strong oxidative decomposition activity when irradiated with visible light based on the fact the divalent copper salt or trivalent iron salt functions as a catalyst for multi-electron reduction of oxygen.

Abstract: The present invention provides a tungsten trioxide microparticle carrying on its surface divalent copper salt. The divalent copper salt is utilized to perform a multi-electron reduction of oxygen. The tungsten trioxide exhibits a high oxidative decomposition activity when exposed to visible light.

Abstract: A divalent copper salt and/or trivalent iron salt is supported on a surface of a metal ion-doped titanium oxide obtained by doping titanium oxide with metal ions to give a metal ion-doped titanium oxide with a valence band potential of 3 V or more (vs. SHE, pH=0) and a bandgap of 3 V or less between the valence band and an energy level of electrons excited from the valence band (including conduction band minimum potential and isolated potential). The metal ion-doped titanium oxide can be made to exhibit strong oxidative decomposition activity when irradiated with visible light based on the fact the divalent copper salt or trivalent iron salt functions as a catalyst for multi-electron reduction of oxygen.

Abstract: The present invention provides a tungsten trioxide microparticle carrying on its surface divalent copper salt. The divalent copper salt is utilized to perform a multi-electron reduction of oxygen. The tungsten trioxide exhibits a high oxidative decomposition activity when exposed to visible light.