Core-shell type catalyst and gas sensor including the catalyst

Patent metadata

Field	Value
Publication number	US-2017269047-A1
Application number	US-201715455113-A
Country	US
Kind code	A1
Filing date	Mar 9, 2017
Priority date	Sep 14, 2015
Publication date	Sep 21, 2017
Grant date	—

Abstract

A core-shell structure (a diameter is about 5 nm) is located on an Al 2 O 3 catalyst support. Platinum (Pt metal) is a core, and a shell that surrounds the core has a solid solution structure (A 1-x B x O Y ) (where X is a composition that composes A and B, and Y is a composition of oxygen (O)) that is composed of platinum, palladium, and oxygen.

First claim

What is claimed is:

1 . A core-shell type catalyst, comprising:
a catalyst particulate including
a core portion comprised of a first metal material consisting of a single metal element, and
a shell portion having a solid-phase structure and being comprised of a plurality of metal materials including the first metal material and a non-metal material consisting of a single non-metal element, the plurality of metal materials each consisting of single metal element that is different from the metal elements of the others of the plurality of metal materials; and
a catalyst support for immobilizing the catalyst particulate.

2 . The core-shell type catalyst according to claim 1 , wherein the plurality of metal materials are the first metal material and a second metal material, the first and second metal materials each being selected from among Pt, Pd, Ag, Au, Ni, Sn, Ir, Rh, Ru, Re, and Co.

3 . The core-shell type catalyst according to claim 1 , wherein the atomic ratio of the atoms included in any one of the metal elements to that of any other 1:1.

4 . The core-shell type catalyst according to claim 1 , wherein the shell portion is composed of the first metal material and a second metal material, and oxygen, the shell portion having a structure that may be expressed by the formula:
A 1-x B x O Y ,
where the first metal material, the second metal material, and the oxygen are represented as A, B and O, respectively, wherein X is a positive number smaller than 1, and Y is a number greater than 0.

5 . The core-shell type catalyst according to claim 4 , wherein the first and second metal materials are Pd and Pt, respectively, X being equal to 0.5, Y being equal to or less than 1.

6 . The core-shell type catalyst according to claim 1 , wherein the catalyst support includes one of the metal oxides among Al 2 O 3 , ZrO 2 , Cr 2 O 3 , Fe 2 O 3 , Ni 2 O 3 , and SiO 2 or another material having a specific surface area in a range of the specific surface areas of Al 2 O 3 , ZrO 2 , Cr 2 O 3 , Fe 2 O 3 , Ni 2 O 3 , and SiO 2 .

7 . The core-shell type catalyst according to claim 1 , wherein the shell portion has a solid-solution structure comprised of the plurality of metal materials and the non-metal material.

8 . A gas sensor, comprising a gas detection unit for detecting a target gas, the gas detection unit including an absorption layer, the absorption layer including core-shell type catalysts according to claim 1 .

9 . A gas sensor, comprising:
a gas detection unit configured to detect whether a target gas exists, the gas detection unit including
an absorption layer that absorbs the target gas to be detected and includes core-shell type catalysts according to claim 1 ,
a gas sensing layer that senses the target gas, and
a heater layer that heats the gas sensing layer; and
a heater layer drive unit configured to heat the heater layer to be within the range 80° C. to 250° C.

10 . A gas sensor, comprising:
a gas detection unit configured to detect whether a target gas exists, the gas detection unit including
an absorption layer that absorbs the target gas to be detected and includes core-shell type catalysts according to claim 1 ,
a gas sensing layer that senses the target gas, and
a heater layer that heats the gas sensing layer; and
a heater layer drive unit configured to heat the heater layer to be within the range 300° C. to 400° C.

11 . A gas sensor, comprising:
a gas detection unit configured to detect whether a target gas exists, the gas detection unit including
an absorption layer that absorbs the target gas to be detected and includes core-shell type catalysts according to claim 1 ,
a gas sensing layer that senses the target gas, and
a heater layer that heats the gas sensing layer; and
a heater layer drive unit configured to heat the heater layer to be within the range 350° C. to 450° C.

12 . The gas sensor according to claim 9 , wherein
the heater layer is heated to be within the range 80° C. to 250° C. by intermittently driving the heater layer drive unit, and the gas sensing layer senses a CO gas as the target gas thought the gas absorption layer.

13 . The gas sensor according to claim 10 , wherein
the heater layer is heated to within the range 300° C. to 400° C. by intermittently driving the heater layer drive unit, and the gas sensing layer senses a liquefied petroleum gas as the target gas thought the gas absorption layer.

14 . The gas sensor according to claim 11 , wherein
the heater layer is heated to within the range 350° C. to 450° C. by intermittently driving the heater layer drive unit, and the gas sensing layer senses a methane gas as the target gas thought the gas absorption layer.

15 . The gas sensor according to claim 12 , further comprising a detection signal processor, wherein
the gas detection unit outputs a gas detection signal including a change between an initial resistance value and a current resistance value that are sensed by the gas sensing layer, and the detection signal processor detects the target gas from the gas detection signal.

16 . The gas sensor according to claim 13 , further comprising a detection signal processor, wherein
the gas detection unit outputs a gas detection signal including a change between an initial resistance value and a current resistance value that are sensed by the gas sensing layer, and the detection signal processor detects the target gas from the gas detection signal.

17 . The gas sensor according to claim 14 , further comprising a detection signal processor, wherein
the gas detection unit outputs a gas detection signal including a change between an initial resistance value and a current resistance value that are sensed by the gas sensing layer, and the detection signal processor detects the target gas from the gas detection signal.

Assignees

• Fuji Electric Co Ltd

Inventors

• Murata Naoyoshi
• Shibuta Yukari
• Suzuki Takuya
• Okamura Makoto

Classifications

• B01J23/42

  Platinum · CPC title

• B01J23/44

  Palladium · CPC title

• G01N33/0016

  by regulating a physical variable, e.g. pressure or temperature · CPC title

• G01N33/0013

  by a chemical reaction (a chemical reaction taking place or a gas being eliminated in one or more analysing channels G01N33/0024) · CPC title

• G01N33/0047 Primary

  Organic compounds · CPC title