Tuning the core-shell ratio in heterojunction nanostructured CuS@In2S3 nanoparticles and photo/electro-catalytic activity evaluation
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Mengxin Liu (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
- Advisor
- Jianjun Wei
Abstract: Nanosized materials have been utilized in the areas of energy conversion and storage, heterogeneous catalysis, biomedicine, textile and more due to their advantages of tunable structures and properties. With the adoption of novel synthetic and fabrication methods, the properties of the nanoscale materials can be varied and improved by controlling the morphology (shape and size), heterojunction structures and/or crystallization, and so on. In this dissertation work, P-type copper sulfide (CuS) and N-type indium sulfide (In2S3) were selected to construct a hybrid heterojunction, nanostructured core-shell CuS@In2S3 nanoparticles (NPs). The hypothesis of this study is that the energy band gap can be tuned by the core-shell ratio in the synthesis, thus leading to the manipulation of the photo- and electro-catalytic activity. We used the microwave-assisted solvothermal method for the core-shell NPs fabrication. Compared with traditional chemical or electrochemical strategy, the microwave method can directly and homogeneously provide the reaction energy on the formation of particles from precursors. Basically, CuS and In2S3 are the members of the family of metal chalcogenide semiconductors, which have proven photo-activity and electrocatalytic activity. Different ratios of the core-shell CuS@In2S3 NPs were obtained for the photodegradation of two dye species, methylene blue (MB) and methyl orange (MO). The structural and morphological studies combining the optical bandgap analysis suggest that the CuS amount used in the synthesis plays an essential role in forming the efficient heterojunction interfaces for charge carrier separation to inhibit the recombination of excited electron and hole pairs and the resultant different optical bandgap of the NPs. The 10 wt% CuS@In2S3 core-shell NPs demonstrate a lower optical band for a wide range visible light absorption and higher photocatalytic activity than that of the CuS NPs, In2S3 NPs, and the 5 wt% CuS, or 15 wt% CuS NPs. In the electrocatalytic study, electrochemistry of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) was performed using the core-shell NPs of different wt% CuS and compared to the CuS NPs and In2S3 NPs. The 10wt% CuS@In2S3 NPs demonstrated the best efficiency and kinetics in the OER and ORR process. Electrochemical impedance and Tafel analysis indicate that the 10wt% CuS@In2S3 NPs offer less resistance and a smaller overpotential for the reactions than any other types of NPs in this study. The mechanism analysis suggests the low energy band gap due to the optimal ratio for the heterojunction interface accounted for the improved electrocatalytic activity. [This abstract may have been edited to remove characters that will not display in this system. Please see the PDF for the full abstract.]
Tuning the core-shell ratio in heterojunction nanostructured CuS@In2S3 nanoparticles and photo/electro-catalytic activity evaluation
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Created on 5/1/2023
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Additional Information
- Publication
- Dissertation
- Language: English
- Date: 2023
- Keywords
- Core-shell nanoparticles, Electrocatalysis, Heterojunction, Kinetics, Photocatalysis, Photodegradation
- Subjects
- Semiconductor nanoparticles
- Electrocatalysis
- Photocatalysis