Crystal-facet and microstructure engineering in ZnO for photocatalytic NO oxidation

Yanshan Wan; Jibiao Li; Jiupai Ni; Chong Wang; Chengsheng Ni; Hong Chen

doi:10.1016/j.jhazmat.2022.129073

Crystal-facet and microstructure engineering in ZnO for photocatalytic NO oxidation

J Hazard Mater. 2022 Aug 5:435:129073. doi: 10.1016/j.jhazmat.2022.129073. Epub 2022 May 5.

Authors

Yanshan Wan¹, Jibiao Li², Jiupai Ni³, Chong Wang⁴, Chengsheng Ni⁵, Hong Chen⁶

Affiliations

¹ College of Resources and Environment, Southwest University, Chongqing 400715, China.
² Center for Materials and Energy (CME) and Chongqing Key Laboratory of Extraordinary Bond Engineering and Advanced Materials Technology (EBEAM), Yangtze Normal University, Chongqing 408100, China.
³ College of Resources and Environment, Southwest University, Chongqing 400715, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China.
⁴ College of Resources and Environment, Southwest University, Chongqing 400715, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China. Electronic address: wangc0928@swu.edu.cn.
⁵ College of Resources and Environment, Southwest University, Chongqing 400715, China; National Base of International S&T Collaboration on Water Environmental Monitoring and Simulation in Three Gorges Reservoir Region, Chongqing 400716, China. Electronic address: nichengsheg@swu.edu.cn.
⁶ College of Resources and Environment, Southwest University, Chongqing 400715, China. Electronic address: chenhong@swu.edu.cn.

PMID: 35650731
DOI: 10.1016/j.jhazmat.2022.129073

Abstract

Photocatalysis is believed to be an important way of reducing NO pollutant in air and the facet engineering of semiconducting oxides could enhance the efficiency of the photocatalysis. ZnO nanoparticles with different exposed crystalline facets were successfully synthesized using a hydrothermal method and their photocatalytic degradation towards NO was investigated. The crystals from ZnCl₂ precursor were hexagonal mesoporous ones with exposed (0002) facet, while those from zinc acetate were in the form of flakes or wheat ears with enhanced exposure of (101(-)1) facet. Calcination in air imparted an enhanced the textural coefficient of the orientated facets as well as the oxygen defects. The nanocrystals with enhanced (0002) facet and lower flat-band energy did better in photoelectrochemical water-oxidation than those with exposed (101(-)1) facet that showed superior photocatalytic activity (approaching 76.7 ± 0.6% under 365 nm photons) for NO oxidation. According to theoretical calculations, (101(-)1) facet with O termination showed much higher affinity to NO molecules than other configurations, and the oxygen vacancy in ZnO played an minor role in the photocatalytic oxidation of NO. A high quantum efficiency approaching 97.5 ± 1.4% under 275 nm photons was obtained for the ZnO crystals from zinc acetate with mixed (0002) and (101(-)1) facets. This research explores the special characteristics of ZnO with different exposed facets and is important for the future design of highly efficient photocatalyst for hazardous material removal.

Keywords: Crystal facets; NO oxidation; Oxide-ion vacancy; Photocatalysis; ZnO.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Oxygen
Zinc Acetate
Zinc Oxide* / chemistry

Substances

Zinc Acetate
Oxygen
Zinc Oxide