# US 10,320,005 B2 · Bismuth-vanadate-laminate manufacturing method and bismuth-vanadate laminate

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- Number: US 10,320,005 B2
- Document ID: US10320005B2
- Status: Granted
- Kind: B2
- Application number: 14/772,643
- Filed: 2014-03-04
- Published: 2016-01-28
- Granted: 2019-06-11
- Earliest claimed: 2013-03-07
- Assignees: Tokyo University of Science Foundation; Mitsui Chemicals, Inc.; Japan Technological Research Association of Artificial Photosynthetic Chemical Process
- Applicants: Tokyo University of Science Foundation; Mitsui Chemicals, Inc.; Japan Technological Research Association of Artificial Photosynthetic Chemical Process
- Inventors: Akihiko Kudo; Qingxin Jia; Akihide Iwase
- Web page: https://patentgrep.com/patent/US10320005B2

## CPC

- H01M 4/9016: {Oxides, hydroxides or oxygenated metallic salts}
- B01J 23/14: of germanium, tin or lead
- B01J 23/22: Vanadium
- B01J 27/135: with titanium, zirconium, hafnium, germanium, tin or lead
- B01J 35/39: Photocatalytic properties
- B01J 35/70: characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00)
- B01J 37/346: {of microwave energy}
- C23C 18/1216: {Metal oxides (C23C18/1212 takes precedence)}
- C23C 18/143: {Radiation by light, e.g. photolysis or pyrolysis}
- C25B 11/091: consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
- H01M 4/8842: {Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor}
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A new BiVO4-laminate manufacturing method and BiVO4 laminate are provided. A bismuth-vanadate laminate is manufactured as follows: a substrate that can be heated by microwaves is disposed inside a precursor solution containing a vanadium salt and a bismuth salt, microwave-activated chemical bath deposition (MW-CBD) is used to form a bismuth-vanadate layer on the substrate, and a firing process is performed as necessary. A bismuth-vanadate laminate manufactured in this way is suitable for use as a photocatalyst or photoelectrode.

## Claims

### Claim 1

A manufacturing method for forming two bismuth-vanadate layers on a substrate, the method comprising:
arranging the substrate in a precursor solution containing a vanadium salt and a bismuth salt,
heating the substrate arranged in the precursor solution by irradiating with microwave radiation thereby forming a first bismuth-vanadate layer on the substrate, and
forming a second bismuth-vanadate layer on the first bismuth-vanadate layer by coating and sintering the precursor solution on the first bismuth-vanadate layer,
wherein ratios of a zircon-structure tetragonal phase and a scheelite-structure monoclinic phase in a crystal phase of the first bismuth-vanadate layer are controlled by controlling at least one of (a) a sintering temperature and (b) a sintering time in the sintering.

### Claim 2 (depends on 1)

The manufacturing method according to claim 1, wherein
the crystal phase of the first bismuth-vanadate layer is a zircon-structure tetragonal phase, and a crystal phase of the second bismuth-vanadate layer is a scheelite-structure monoclinic phase.

### Claim 3 (depends on 1)

The manufacturing method according to claim 1, wherein irradiation power of the microwave radiation is from 100 to 500 W.

### Claim 4 (depends on 3)

The manufacturing method according to claim 3, wherein irradiation time of the microwave radiation is from 1 to 30 minutes.

### Claim 5 (depends on 1)

The manufacturing method according to claim 1, wherein the sintering is performed at a temperature of 100 to 550° C. for a duration of 0.5 to 5 hours.

### Claim 6 (depends on 1)

The manufacturing method according to claim 1, wherein the substrate is a glass or a resin substrate including a conductive film.

### Claim 7 (depends on 6)

The manufacturing method according to claim 6, wherein the conductive film is selected from the group consisting of tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), fluorine-doped in tin-oxide (FTO), and aluminum-doped zinc oxide (AZO).