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Gupta A, Bhoyar T, Abraham BM, Kim DJ, Pasupuleti KS, Umare SS, Vidyasagar D, Gedanken A. Potassium Molten Salt-Mediated In Situ Structural Reconstruction of a Carbon Nitride Photocatalyst. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18898-18906. [PMID: 37018662 DOI: 10.1021/acsami.3c00239] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Metal-free polymeric carbon nitride (PCN) materials are at the forefront of photocatalytic applications. Nevertheless, the overall functionality and performance of bulk PCN are limited by rapid charge recombination, high chemical inertness, and inadequate surface-active sites. To address these, here, we employed potassium molten salts (K+X-, where X- is Cl-, Br-, and I-) as a template for the in situ generation of surface reactive sites in thermal pyrolyzed PCN. Theoretical calculations imply that addition of KX salts to PCN-forming monomers causes halogen ions to be doped into C or N sites of PCN with a relative trend of halogen ion doping being Cl < Br < I. The experimental results show that reconstructing C and N sites in PCN develops newer reactive sites that are beneficial for surface catalysis. Interestingly, the photocatalytic H2O2 generation rate of KBr-modified PCN was 199.0 μmol h-1, about three times that of bulk PCN. Owing to the simple and straightforward approach, we expect molten salt-assisted synthesis to have wide exploration in modifying PCN photocatalytic activity.
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Affiliation(s)
- Akanksha Gupta
- Bar-Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Toshali Bhoyar
- Materials and Catalysis Laboratory, Department of Chemistry, Visvesvaraya National Institute of Technology (VNIT), Nagpur, 440010 Maharashtra, India
| | - B Moses Abraham
- Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Dong Jin Kim
- School of Energy Engineering, Kyungpook National University, Buk-gu, Daegu 41566, Republic of Korea
| | | | - Suresh S Umare
- Materials and Catalysis Laboratory, Department of Chemistry, Visvesvaraya National Institute of Technology (VNIT), Nagpur, 440010 Maharashtra, India
| | - Devthade Vidyasagar
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Aharon Gedanken
- Bar-Ilan Institute for Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 5290002, Israel
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Chuaicham C, Noguchi Y, Shenoy S, Shu K, Trakulmututa J, Srikhaow A, Sekar K, Sasaki K. Simultaneous Photocatalytic Sugar Conversion and Hydrogen Production Using Pd Nanoparticles Decorated on Iron-Doped Hydroxyapatite. Catalysts 2023. [DOI: 10.3390/catal13040675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Pd nanoparticles (PdNPs) were successfully deposited on the surface of Fe(III)-modified hydroxyapatite (HAp), which was subsequently used as a photocatalyst for simultaneous photocatalytic H2 evolution and xylose conversion. The structural phase and morphology of the pristine HAp, FeHAp, and Pd@FeHAp were examined using XRD, SEM, and TEM instruments. At 20 °C, Pd@FeHAp provided a greater xylose conversion than pristine HAp and FeHAp, about 2.15 times and 1.41 times, respectively. In addition, lactic acid and formic acid production was increased by using Pd@FeHAp. The optimal condition was further investigated using Pd@FeHAp, which demonstrated around 70% xylose conversion within 60 min at 30 °C. Moreover, only Pd@FeHAp produced H2 under light irradiation. To clarify the impact of Fe(III) doping in FeHAp and heterojunction between PdNPs and FeHAp in the composite relative to pure Hap, the optical and physicochemical properties of Pd@FeHAp samples were analyzed, which revealed the extraordinary ability of the material to separate and transport photogenerated electron-hole pairs, as demonstrated by a substantial reduction in photoluminescence intensity when compared to Hp and FeHAp. In addition, a decrease in electron trap density in the Pd@FeHAp composite using reversed double-beam photoacoustic spectroscopy was attributed to the higher photocatalytic activity rate. Furthermore, the development of new electronic levels by the addition of Fe(III) to the structure of HAp in FeHAp may improve the ability to absorb light by lessening the energy band gap. The photocatalytic performance of the Pd@FeHAp composite was improved by lowering charge recombination and narrowing the energy band gap. As a result, a newly developed Pd@FeHAp composite might be employed as a photocatalyst to generate both alternative H2 energy and high-value chemicals.
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Affiliation(s)
- Chitiphon Chuaicham
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Yuto Noguchi
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Sulakshana Shenoy
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Kaiqian Shu
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Jirawat Trakulmututa
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Assadawoot Srikhaow
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
| | - Karthikeyan Sekar
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
- Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Keiko Sasaki
- Department of Earth Resources Engineering, Kyushu University, Fukuoka 819-0395, Japan
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Abstract
Photocatalysis represents a promising technology that might alleviate the current environmental crisis. One of the most representative photocatalysts is graphitic carbon nitride (g-C3N4) due to its stability, cost-effectiveness, facile synthesis procedure, and absorption properties in visible light. Nevertheless, pristine g-C3N4 still exhibits low photoactivity due to the rapid recombination of photo-induced electron-hole (e−-h+) pairs. To solve this drawback, Z-scheme photocatalysts based on g-C3N4 are superior alternatives since these systems present the same band configuration but follow a different charge carrier recombination mechanism. To contextualize the topic, the main drawbacks of using g-C3N4 as a photocatalyst in environmental applications are mentioned in this review. Then, the basic concepts of the Z-scheme and the synthesis and characterization of the Z-scheme based on g-C3N4 are addressed to obtain novel systems with suitable photocatalytic activity in environmental applications (pollutant abatement, H2 production, and CO2 reduction). Focusing on the applications of the Z-scheme based on g-C3N4, the most representative examples of these systems are referred to, analyzed, and commented on in the main text. To conclude this review, an outlook of the future challenges and prospects of g-C3N4-based Z-scheme photocatalysts is addressed.
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