Novel Nanostructured Photocatalysts for Environmental and Energy Applications

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Energy and Catalysis".

Deadline for manuscript submissions: 20 May 2024 | Viewed by 5812

Special Issue Editors


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Guest Editor
School of Environmental Science and Engineering, Shandong University, Qingdao, China
Interests: functional nanocomposites; plasmonic nanoparticles; photocatalysis; wastewater treatment; solar water splitting; mercury transformations

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Guest Editor
School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China
Interests: functional nanocomposites; plasmonic photocatalysis; solar water splitting

Special Issue Information

Dear Colleagues,

Photocatalysis, which can directly harvest and convert solar energy for environmental remediation, has been recognized as a green, sustainable, and ideal avenue to address global environmental pollution and energy crisis concerns. At the heart of the photocatalytic system is an advanced photocatalyst, with recent decades having witnessed the development of effective nanostructured photocatalysts for removing environmental pollutants and producing green fuels. The design and synthesis of nanostructured photocatalysts and their related composites have been the subject of extensive research, introducing novel opportunities and challenges for their catalytic applications.

Since this fast-moving research area is beginning to pose and answer questions that determine the photocatalytic performance of nanomaterials, it is an opportune time to look at the progress thus far, and point out future directions in this field. Therefore, this Special Issue intends to draw attention to and assess recent advances in the design and synthesis of nanostructures/nanocomposites and their photocatalytic applications in environmental remediation and fuel production. It is expected to provide more insights into the understanding of the relationships between nanostructures and their photocatalytic properties. It also aims investigate current challenges and perspectives in this dynamic field.

We invite submissions in the form of original research articles as well as reviews and mini-reviews. We are particularly interested in articles regarding the synthesis of nanostructured photocatalysts and their environmental and energy applications. Topics to be covered in this Special Issue include, but are not limited to:

  • Photocatalysts with different morphologies;
  • Nanocomposite photocatalysts;
  • Photocatalytic degradation of environmental pollutants;
  • Photocatalytic H2 evolution;
  • Photocatalytic CO2 reduction;
  • Photocatalytic inactivation of pathogens, such as viruses and bacteria;
  • Photocatalytic detoxication of heavy metals;
  • Photocatalytic processes in the degradation of emerging contaminants;
  • Photocatalytic mechanism exploration;
  • Advanced characterizations to reveal charge dynamics in photocatalysis.

Prof. Dr. Qingzhe Zhang
Prof. Dr. Hongyan Liang
Guest Editors

Manuscript Submission Information

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Keywords

  • nanostructures
  • nanocomposites
  • photocatalysts
  • environmental remediation
  • solar water splitting
  • CO2 reduction
  • photocatalytic disinfection

Published Papers (4 papers)

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Research

23 pages, 9881 KiB  
Article
Effect of Co Doping on the Physical Properties and Organic Pollutant Photodegradation Efficiency of ZnO Nanoparticles for Environmental Applications
by Hajer Saadi, Othmen Khaldi, João Pina, Telma Costa, J. Sérgio Seixas de Melo, Paula Vilarinho and Zohra Benzarti
Nanomaterials 2024, 14(1), 122; https://doi.org/10.3390/nano14010122 - 4 Jan 2024
Viewed by 1054
Abstract
This paper presents a comprehensive investigation of the synthesis and characterization of Zn1−xCoxO (0 ≤ x ≤ 0.05) nanopowders using a chemical co-precipitation approach. The structural, morphological, and vibrational properties of the resulting ZnO nanostructures were assessed through X-ray [...] Read more.
This paper presents a comprehensive investigation of the synthesis and characterization of Zn1−xCoxO (0 ≤ x ≤ 0.05) nanopowders using a chemical co-precipitation approach. The structural, morphological, and vibrational properties of the resulting ZnO nanostructures were assessed through X-ray diffraction, scanning electronic microscopy, and Raman spectroscopy to examine the influence of cobalt doping. Remarkably, a notable congruence between the experimental results and the density functional theory (DFT) calculations for the Co-doped ZnO system was achieved. Structural analysis revealed well-crystallized hexagonal wurtzite structures across all samples. The SEM images demonstrated the formation of spherical nanoparticles in all the samples. The vibrational properties confirmed the formation of a hexagonal wurtzite structure, with an additional Raman peak corresponding to the F2g vibrational mode characteristic of the secondary phase of ZnCo2O4 observed at a 5% cobalt doping concentration. Furthermore, a theoretical examination of cobalt doping’s impact on the elastic properties of ZnO demonstrated enhanced mechanical behavior, which improves stability, recyclability, and photocatalytic activity. The photocatalytic study of the synthesized compositions for methylene blue (MB) dye degradation over 100 min of UV light irradiation demonstrated that Co doping significantly improves photocatalytic degradation. The material’s prolonged lifetime, reduced rate of photogenerated charge carrier recombination, and increased surface area were identified as pivotal factors accelerating the degradation process. Notably, the photocatalyst with a Zn0.99Co0.01O composition exhibited exceptional efficiency compared to that reported in the literature. It demonstrated high removal activity, achieving an efficiency of about 97% in a shorter degradation time. This study underscores the structural and photocatalytic advancements in the ZnO system, particularly at lower cobalt doping concentrations (1%). The developed photocatalyst exhibits promise for environmental applications owing to its superior photocatalytic performance. Full article
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15 pages, 6221 KiB  
Article
Sulfur Vacancy-Rich CuS for Improved Surface-Enhanced Raman Spectroscopy and Full-Spectrum Photocatalysis
by Jiapei Hu, Yinyan Gong, Lengyuan Niu, Can Li and Xinjuan Liu
Nanomaterials 2023, 13(1), 128; https://doi.org/10.3390/nano13010128 - 26 Dec 2022
Cited by 3 | Viewed by 1586
Abstract
There are growing interests in the development of bifunctional semiconducting nanostructures for photocatalysis and real-time monitoring of degradation process on catalysts. Defect engineering is a low-cost approach to manipulating the properties of semiconductors. Herein, we prepared CuS nanoplates by a hydrothermal method at [...] Read more.
There are growing interests in the development of bifunctional semiconducting nanostructures for photocatalysis and real-time monitoring of degradation process on catalysts. Defect engineering is a low-cost approach to manipulating the properties of semiconductors. Herein, we prepared CuS nanoplates by a hydrothermal method at increasing amounts of thioacetamide (CS-1, CS-2, and CS-3) and investigated the influence of sulfur vacancy (Vs) on surface-enhanced Raman spectroscopy (SERS) and photocatalysis performance. SERS intensity of 4-nitrobenzenethiol on CS-3 is 346 and 17 times that of CS-1 and CS-2, respectively, and enhancement factor is 1.34 × 104. Moreover, SERS is successfully applied to monitor the photodegradation of methyl orange. In addition, CS-3 also exhibited higher efficiency of Cr(VI) photoreduction than CS-1 and CS-2, and removal rate is 88%, 96%, and 73% under 2 h UV, 4 h visible, and 4 h near-infrared illumination, respectively. A systematic study including electron paramagnetic resonance spectra, photoelectrochemical measurements, and nitrogen adsorption isotherms were conducted to investigate the underlying mechanism. This work may help to understand the impact of vacancy defect on SERS and photocatalysis, and provide an effective and low-cost approach for the design of multifunctional materials. Full article
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19 pages, 4704 KiB  
Article
The Role of Nitrogen-Doped TiO2 Supported by Platinum Catalyst Synthesized via Various Mode Preparations for Photocatalytic Enhancement
by Nadiah Sabihah Natar, Nureel Imanina Abdul Ghani, Siti Raihan Hamzah, Muhammad Afiq Rosli, Nur Aien Muhamad, Mohammad Saifulddin Azami, Mohd Azlan Mohd Ishak, Sharin Razak and Wan Izhan Nawawi
Nanomaterials 2022, 12(22), 3998; https://doi.org/10.3390/nano12223998 - 13 Nov 2022
Cited by 2 | Viewed by 1153
Abstract
The limitations of TiO2 as a photocatalyst such as the larger bandgap energy, which only activates under the UV region, give a lower photocatalytic activity. This study reports the role of the N and Pt co-dopant on the modification of the TiO [...] Read more.
The limitations of TiO2 as a photocatalyst such as the larger bandgap energy, which only activates under the UV region, give a lower photocatalytic activity. This study reports the role of the N and Pt co-dopant on the modification of the TiO2 photocatalyst for photocatalytic degradation of methylene blue dye under different mode preparations, i.e., sequential and vice-versa modes. The sequential mode preparation of the N and Pt co-dopant TiO2 photocatalyst consisted of the initial preparation of the N-doped TiO2 (N-TiO2) under the calcination method, which was then further doped with platinum (Pt) through the photodeposition process labeled as NPseq-TiO2, while the vice-versa mode was labeled as PNrev-TiO2. About 1.58 wt.% of N element was found in the NPseq-TiO2 photocatalyst, while there was no presence of N element detected in PNrev-TiO2, confirmed through an elemental analyzer (CHNS-O) and (EDX) analysis. The optimum weight percentage of Pt for both modes was detected at about ±2.0 wt.%, which was confirmed by inductively coupled plasma-emission spectroscopy (ICP-OES). The photoactivity under methylene blue (MB) dye degradation of the NPseq-TiO2 photocatalyst was 2 and 1.5 times faster compared to the unmodified TiO2 and PNrev-TiO2, where the photodegradation rates were, ca., 0.065 min−1 and 0.078 min−1, respectively. This was due to the N elements being incorporated with the TiO2 lattice, which was proven by UV-Vis/DRS where the bandgap energy of NPseq-TiO2 was reduced from 3.2 eV to 2.9 eV. In addition, the N generated a stronger PL signal due to the formation of oxygen vacancies defects on the surface of the NPseq-TiO2 photocatalyst. The higher specific surface area as well as higher pore volume for the NPseq-TiO2 photocatalyst enhanced its photocatalytic activity. Moreover, the NPseq-TiO2 showed the lowest COD value, and it was completely mineralized after 7 h of light irradiation. The preparation order did not affect the Pt dopant but did for the N element. Therefore, it is significant to investigate different mode preparations of the N and Pt co-dopant for the modification of TiO2 to produce a good-quality photocatalyst for photocatalytic study under the photodegradation of MB dye. Full article
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10 pages, 2890 KiB  
Article
A Simple Fabrication of Sb2S3/TiO2 Photo-Anode with Long Wavelength Visible Light Absorption for Efficient Photoelectrochemical Water Oxidation
by Fei Han, Sai Ma, Dong Li, Md Mofasserul Alam and Zeheng Yang
Nanomaterials 2022, 12(19), 3444; https://doi.org/10.3390/nano12193444 - 1 Oct 2022
Cited by 2 | Viewed by 1711
Abstract
An Sb2S3-sensitized TiO2 (Sb2S3/TiO2) photo-anode (PA) exhibiting a high photo-electrochemical (PEC) performance in water oxidation has been successfully prepared by a simple chemical bath deposition (CBD) technique. Herein, the Raman spectra and [...] Read more.
An Sb2S3-sensitized TiO2 (Sb2S3/TiO2) photo-anode (PA) exhibiting a high photo-electrochemical (PEC) performance in water oxidation has been successfully prepared by a simple chemical bath deposition (CBD) technique. Herein, the Raman spectra and XPS spectrum of Sb2S3/TiO2 confirmed the formation of Sb2S3 on the TiO2 coatings. The Sb2S3/TiO2 photo-anode significantly shifted the absorption edge from 395 nm (3.10 eV) to 650 nm (1.90 eV). Furthermore, the Sb2S3/TiO2 photo-anode generated a photo-anodic current under visible light irradiation below 650 nm due to the photo-electrochemical action compared with the TiO2 photo-anode at 390 nm. The incident photon-to-current conversion efficiency (IPCE = 7.7%) at 400 nm and −0.3 V vs. Ag/AgCl was 37 times higher than that (0.21%) of the TiO2 photo-anodes due to the low recombination rate and acceleration of the carriers of Sb2S3/TiO2. Moreover, the photo-anodic current and photostability of the Sb2S3/TiO2 photo-anodes improved via adding the Co2+ ions to the electrolyte solution during photo-electrocatalysis. Full article
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