Characterization and visible light photocatalytic activity of metal oxidebismuth vanadate powder synthesized by an ethanol-assisted hydrothermal method

คุณลักษณะเฉพาะและความสามารถในการเร่งปฏิกิริยาด้วยแสงของ ผงโลหะออกไซด์บิสมัธวานาเดตที่สังเคราะห์ด้วยวิธีเอทานอล ร่วมกับไฮโดรเทอร์มอล

Name: Pradudnet Ketwong

keyword: bBismuth vanadate

LCSH: Maejo University -- Dissertation

; Bismuth tungstate

LCSH: Hydrothermal alteration

; Photocatalysis

LCSH: Catalysts

; Stabilization

Abstract: Bismuth vanadate (BIVOA) is a semiconductor with a localized electronic structure that facilitates photocatalysis under visible light. The efficiency of such photocatalyst is not high due to physical and chemical properties limitations. This research presents the results of an ethanol-assisted hydrothermal synthesis of BiVO4 as well as the effects of the BIVO, synthesis conditions, such as pH, temperature and reaction time, that affect the decomposition capacity of methyl orange (MO) and oxygen production. It was found that pH, reaction temperature and reaction time affects directly on the crystalline structure and crystallinity of BIVO4. Single monoclinic structure could be synthesized at pH 7 and 8, and the crystallinity was increased by increasing the reaction temperature and reaction time. In addition, the parameters also contributed significantly to the morphology of BiVO4 particles, including particle size, surface area, electronic structure and arrangement of atoms in the crystal structure. These characteristics significantly affected the photocatalytic efficiency of the BiVO4. The BIVO, with monoclinic structure, high crystallinity, a great surface area and a distortion of the V-O bond is the most active photocatalyst for photocatalysis under visible light. Moreover, stability and sustainability of the photocatalytic rate are also important. Bismuth vanadate/bismuth tungstate (BIVO/Bi2W06) composites in various molar ratios were synthesized in the same way as the BIVO4. Photocatalytic activity results demonstrated that BiVO, powder had the highest efficiency. It was also found that, the BIVO/BiZWO6 composites activities were based on the fraction of BIVO, without synergetic effect. This finding was supported by results of energy resolved distribution of electron traps. However, after calcination at 600 ?C for 4 h, photocatalytic oxygen liberation was enhanced by the combination of BIVO, (80%) and BiZWO. (20%) followed by calcination. Furthermore, the calcined BIVO/Bi,WO6 composite had superior advantages over BiVO4 in stability and reusability. Based on this research, the BIVO4 with highly efficiency visible-light absorption has been developed for future photocatalyst in order to overcome its disadvantages, such as low stability and rapid electron-hole recombination rate under light irradiation, which decrease photocatalytic activity of the BIVO4.

มหาวิทยาลัยแม่โจ้. สำนักหอสมุด

Address: เชียงใหม่

Email: mjudc@mju.ac.th

Name: Pusit Pookmanee

Role: Chair

Name: Supaporn Sangsrichan

Role: Committee

Name: Pinit Kidkhunthod

Role: Committee

Name: Supaporn Sangsrichan

Role: Program Chair

Created: 2017

Modified: 2564-09-01

Issued: 2564-09-01

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: 541.395 P000c 2017

tha

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Applied Chemistry

Grantor: Maejo University

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