Method for improving solar energy conversion efficiency of semiconductor metal oxide photocatalysis using h2/n2 mixed gas plasma treatment

Patent metadata

Field	Value
Publication number	US-2016376716-A1
Application number	US-201514925431-A
Country	US
Kind code	A1
Filing date	Oct 28, 2015
Priority date	Jun 29, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

Disclosed is a method for improving solar energy conversion efficiency of a metal oxide semiconductor photocatalyst, which includes rapidly performing hydrogenation and nitrogenation of a metal oxide semiconductor material through an H 2 /N 2 mixed gas plasma treatment in a single process at room temperature, so as to enhance photocatalytic energy conversion efficiency. Specifically, disclosed is a treatment technique in which a plasma ball formed by controlling a mixing ratio of hydrogen gas to nitrogen gas in a range of 1:1 to 1:3 contacts with a surface of a metal oxide material, such that a great amount of oxygen vacancy and nitrogen elements are introduced in the surface of the metal oxide material to improve electron-hole pairs transfer ability thereof and decrease a size of the band-gap. A catalyst including the metal oxide material directly converts the solar energy into a compound by photocatalytic hydrogen generation and CO 2 conversion.

First claim

What is claimed is:

1 . A method for improving solar energy conversion efficiency of a metal oxide semiconductor photocatalyst, comprising: a first process of preparing a metal oxide thin film having n-type semiconductor properties; and a second process of performing a hydrogen and nitrogen mixed gas plasma treatment on the metal oxide thin film.

2 . The method according to claim 1 , wherein the metal is at least one selected from Ti, V, Fe, Ni, Cu, Zn, Sn, Ta, W and Bi.

3 . The method according to claim 1 , wherein the second process includes contacting a plasma sphere formed by an H 2 /N 2 mixed gas plasma reaction with a surface or particle of the metal oxide thin film in a single process at room temperature to enhance photocatalytic properties and efficiency.

4 . The method according to claim 3 , wherein radicals included in the H 2 /N 2 mixed gas plasma are hydrogen radicals (H + ), nitrogen radicals (N + ) and hydrogenated nitrogen radicals (NH x + ).

5 . The method according to claim 1 , wherein a mixing ratio of hydrogen gas to nitrogen gas in the second process is 1:1, 1:2 or 1:3.

6 . The method according to claim 1 , wherein the metal oxide thin film shows metal oxide properties maintained inside while having an amorphous core-shell structure formed on the outside thereof by the hydrogen and nitrogen plasma treatment.

7 . A catalyst for direct conversion of solar energy into a compound, comprising the metal oxide material formed by the H 2 /N 2 mixed gas plasma treatment according to claim 1 , which is adapted to directly convert the solar energy into the compound by hydrogen and CO 2 conversion.

Assignees

• Korea Advanced Inst Sci & Tech

Inventors

• Kang Jeung Ku
• Lee Dong Ki
• Lee Gyu Heon
• Kim Yong-Hoon
• Choi Ji Il

Classifications

• B01J23/06

  of zinc, cadmium or mercury · CPC title

• B01J23/72

  Copper · CPC title

• B01J35/53

  with a core-shell structure · CPC title

• H10F71/128

  Annealing · CPC title

• H10F77/169

  Thin semiconductor films on metallic or insulating substrates · CPC title