Abstract: A semiconductor material of the present invention is a semiconductor material including an oxynitride containing at least one element selected from the Group 4 elements and Group 5 elements. In the oxynitride, part of at least one selected from oxygen and nitrogen is substituted with carbon. Nb is preferable as the Group 5 element.

Abstract: A photoelectrode (100) of the present invention includes a conductive layer (12) and a photocatalytic layer (13) provided on the conductive layer (12). The conductive layer (12) is made of a metal nitride. The photocatalytic layer (13) is made of at least one selected from the group consisting of a nitride semiconductor and an oxynitride semiconductor. When the photocatalytic layer (13) is made of a n-type semiconductor, the energy difference between the vacuum level and the Fermi level of the conductive layer (12) is smaller than the energy difference between the vacuum level and the Fermi level of the photocatalytic layer (13). When the photocatalytic layer (13) is made of a p-type semiconductor, the energy difference between the vacuum level and the Fermi level of the conductive layer (12) is larger than the energy difference between the vacuum level and the Fermi level of the photocatalytic layer (13).

Abstract: A hydrogen producing cell of the present invention is provided with an electrolyte supply hole, an electrolyte discharge hole, a first hydrogen circulation hole and a second hydrogen circulation hole respectively penetrating a housing. In disposing the hydrogen producing cell, the electrolyte supply hole is arranged on a vertically upper side than the electrolyte discharge hole, the first hydrogen circulation hole is arranged on a vertically upper side than the electrolyte supply hole, and the second hydrogen circulation hole is arranged on a vertically upper side than the electrolyte discharge hole. By this configuration, it is possible to considerably reduce the length of a pipe and the number of manifolds concerning the electrolyte and hydrogen, and to link the hydrogen producing cells with one another simply and rationally.

Abstract: A photoelectrochemical cell (100) includes: a semiconductor electrode (120) including a conductor (121) and semiconductor layers (122, 123) disposed on the conductor (121); a counter electrode (130) connected electrically to the conductor (121); an electrolyte (140) in contact with surfaces of the semiconductor layer (123) and the counter electrode (130); and a container (110) accommodating the semiconductor electrode (120), the counter electrode (130) and the electrolyte (140). A band edge level ECS of a conduction band, a band edge level EVS of a valence band, and a Fermi level EFS in a surface near-field region of the semiconductor layer, and a band edge level ECJ of a conduction band, a band edge level EVJ of a valence band, and a Fermi level EFJ in a junction plane near-field region of the semiconductor layer with the conductor satisfy, relative to a vacuum level, ECS?EFS>ECJ?EFJ, EFS?EVS<EFJ?EVJ, ECJ>?4.44 eV, and EVS<?5.67 eV.

Abstract: The present invention is a niobium nitride which has a composition represented by the composition formula Nb3N5 and in which a constituent element Nb has a valence of substantially +5. The method for producing the niobium nitride of the present invention includes the step of nitriding an organic niobium compound by reacting the organic niobium compound with a nitrogen compound gas.

Abstract: The present invention is a niobium nitride which has a composition represented by the composition formula Nb3N5 and in which a constituent element Nb has a valence of substantially +5. The method for producing the niobium nitride of the present invention includes the step of nitriding an organic niobium compound by reacting the organic niobium compound with a nitrogen compound gas.

Abstract: The hydrogen production device of the present invention includes: a first electrode including a conductive substrate and a photocatalytic semiconductor layer; a second electrode that is electrically connected to the first electrode and disposed in a second region opposite to a first region relative to the first electrode; the first region is defined as a region on a side of a surface of the first electrode in which the photocatalytic semiconductor layer is provided; a water-containing electrolyte solution; and a housing containing these. The first electrode is provided with first through-holes and the second electrode is provided with second through-holes; and the first through-holes and second through-holes form a communicating hole for allowing the first region and the second region to communicate with each other. An ion exchange membrane having substantially the same shape as the communicating hole is disposed in the communicating hole to close the communicating hole.

Abstract: Provided is a semiconductor photoelectrode comprising a conductive substrate; a first semiconductor photocatalyst layer provided on a surface of the conductive substrate; a second semiconductor photocatalyst layer provided on a surface of the first semiconductor photocatalyst layer. The semiconductor photoelectrode has a plurality of pillar protrusions on the surface thereof. A surface of each of the pillar protrusions is formed of the second semiconductor photocatalyst layer.

Abstract: The optically pumped semiconductor according to the present invention is an optically pumped semiconductor that is a semiconductor of a perovskite oxide. The optically pumped semiconductor has a composition represented by a general formula: BaZr1-xMxO3-?, where M denotes at least one element selected from trivalent elements, x denotes a numerical value more than 0 but less than 0.8, and ? denotes an amount of oxygen deficiency that is a numerical value more than 0 but less than 1.5. The optically pumped semiconductor has a crystal system of a cubic, tetragonal, or orthorhombic crystal. When lattice constants of the crystal system are referred to as a, b, and c, provided that a?b?c, conditions that 0.41727 nm?a, b, c?0.42716 nm and a/c?0.98 are satisfied.

Abstract: A photoelectrochemical cell (100) includes: a semiconductor electrode (120) including a conductor (121), a first n-type semiconductor layer (122) having a nanotube array structure, and a second n-type semiconductor layer (123); a counter electrode (130) connected to the conductor (121); an electrolyte (140) in contact with the second n-type semiconductor layer (123) and the counter electrode (130); and a container (110) accommodating the semiconductor electrode (120), the counter electrode (130) and the electrolyte (140).

Abstract: A semiconductor material of the present invention is a semiconductor material including an oxynitride containing at least one element selected from the Group 4 elements and Group 5 elements. In the oxynitride, part of at least one selected from oxygen and nitrogen is substituted with carbon. Nb is preferable as the Group 5 element.

Abstract: A hydrogen generation device (100) of the present invention includes: a transparent substrate (1); a photocatalytic electrode (4) formed of a transparent conductive layer (2) and a photocatalytic layer (3) disposed on the transparent substrate (1); a counter electrode (8) connected electrically to the transparent conductive layer (2); a water-containing electrolyte solution layer provided between the photocatalytic electrode (3) and the counter electrode (8); a separator (6) that separates the electrolyte solution layer into a first electrolyte solution layer (5) in contact with the photocatalytic electrode (4) and a second electrolyte solution layer (7) in contact with the counter electrode (8); a first gas outlet (14) for discharging a gas generated in the first electrolyte solution layer (5); and a second gas outlet (15) for discharging a gas generated in the second electrolyte solution layer (7).

Abstract: A hydrogen producing cell of the present invention is provided with an electrolyte supply hole, an electrolyte discharge hole, a first hydrogen circulation hole and a second hydrogen circulation hole respectively penetrating a housing. In disposing the hydrogen producing cell, the electrolyte supply hole is arranged on a vertically upper side than the electrolyte discharge hole, the first hydrogen circulation hole is arranged on a vertically upper side than the electrolyte supply hole, and the second hydrogen circulation hole is arranged on a vertically upper side than the electrolyte discharge hole. By this configuration, it is possible to considerably reduce the length of a pipe and the number of manifolds concerning the electrolyte and hydrogen, and to link the hydrogen producing cells with one another simply and rationally.

Abstract: The method for producing the optical semiconductor of the present disclosure includes a mixing step of producing a mixture containing a reduction inhibitor and a niobium compound that contains at least oxygen in its composition; a nitriding step of nitriding the mixture by the reaction between the mixture and a nitrogen compound gas; and a washing step of isolating niobium oxynitride from the material obtained through the nitriding step by dissolving chemical species other than niobium oxynitride with a washing liquid. The optical semiconductor of the present disclosure substantially consists of niobium oxynitride having a crystal structure of baddeleyite and having a composition represented by the composition formula, NbON.

Abstract: The present invention is a niobium nitride which has a composition represented by the composition formula Nb3N5 and in which a constituent element Nb has a valence of substantially +5. The method for producing the niobium nitride of the present invention includes the step of nitriding an organic niobium compound by reacting the organic niobium compound with a nitrogen compound gas.

Abstract: A photoelectrode (100) of the present invention includes a conductive layer (12) and a photocatalytic layer (13) provided on the conductive layer (12). The conductive layer (12) is made of a metal nitride. The photocatalytic layer (13) is made of at least one selected from the group consisting of a nitride semiconductor and an oxynitride semiconductor. When the photocatalytic layer (13) is made of a n-type semiconductor, the energy difference between the vacuum level and the Fermi level of the conductive layer (12) is smaller than the energy difference between the vacuum level and the Fermi level of the photocatalytic layer (13). When the photocatalytic layer (13) is made of a p-type semiconductor, the energy difference between the vacuum level and the Fermi level of the conductive layer (12) is larger than the energy difference between the vacuum level and the Fermi level of the photocatalytic layer (13).

Abstract: An energy system includes an solar hydrogen producing unit (101) that produces hydrogen through decomposition of water by a photocatalytic effect, a fuel cell (103) that generates electricity by a reaction between the hydrogen produced by the solar hydrogen producing unit (101) and an oxidizing gas and discharges water as a reaction product, and a water distribution mechanism (104) that returns the water serving as the reaction product discharged from the fuel cell (103) to the solar hydrogen producing unit (101). With the configuration, an energy system that suppresses an amount of external water supply to a low level to achieve good water balance can be provided.

Abstract: A titanium oxide photocatalyst that is capable of improving a decomposition rate, and a method for producing the same are provided. The titanium oxide photocatalyst of the present invention is a titanium oxide photocatalyst containing at least an anatase-type titanium oxide and fluorine, wherein a content of the fluorine is 2.5 wt % to 3.5 wt %, and 90 wt % or more of the fluorine is chemically bonded to the anatase-type titanium oxide.

Abstract: A photoelectrochemical cell (1) is a photoelectrochemical cell for decomposing water by irradiation with light so as to produce hydrogen.

Abstract: The hydrogen production device of the present invention includes: a first electrode (120) including a conductive substrate (101) and a photocatalytic semiconductor layer (102); a second electrode (103) that is electrically connected to the first electrode (120) and disposed in a second region (123) opposite to a first region (122) relative to the first electrode (120), when the first region (122) is defined as a region on a side of a surface of the first electrode (120) in which the photocatalytic semiconductor layer (102) is provided; a water-containing electrolyte solution (106); and a housing (105) containing these. The first electrode (120) is provided with a through-hole (131) at a position and the second electrode (103) is provided with a through-hole (132) at a position corresponding to the position, and the through-holes form a communicating hole (130) for allowing the first region (122) and the second region (123) to communicate with each other.