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Kang H, Washington A, Capobianco MD, Yan X, Cruz VV, Weed M, Johnson J, Johns G, Brudvig GW, Pan X, Gu J. Concentration-Dependent Photocatalytic Upcycling of Poly(ethylene terephthalate) Plastic Waste. ACS MATERIALS LETTERS 2023; 5:3032-3041. [PMID: 37969139 PMCID: PMC10630977 DOI: 10.1021/acsmaterialslett.3c01134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 10/10/2023] [Indexed: 11/17/2023]
Abstract
Photocatalytic plastic waste upcycling into value-added feedstock is a promising way to mitigate the environmental issues caused by the nondegradable nature of plastic waste. Here, we developed a MoS2/g-C3N4 photocatalyst that can efficiently upcycle poly(ethylene terephthalate) (PET) into valuable organic chemicals. Interestingly, the conversion mechanism is concentration-dependent. For instance, at a low ethylene glycol (EG) concentration (7.96 mM), acetate is the main product. Unexpectedly, the conversion of PET water bottle hydrolysate with only 7.96 mM ethylene glycol (EG) can produce a 4 times higher amount of acetate (704.59 nmol) than the conversion of 300 mM EG (174.50 nmol), while at a higher EG concentration (300 mM), formate is the dominant product. Herein, a 40 times higher EG concentration (300 mM compared to 7.96 mM) would produce only ∼3 times more formate (179 nmol compared to 51.86 nmol). In addition, under natural sunlight conditions, comparable amounts of liquid and gaseous products are produced when commercial PET plastics are employed. Overall, the photocatalytic PET conversion process is quite efficient under a low concentration of EG in PET hydrolysate, indicating the enormous potential of this photocatalysis strategy for real plastics upcycling.
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Affiliation(s)
- Hongxing Kang
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Audrey Washington
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Matt D. Capobianco
- Department
of Chemistry and Yale Energy Sciences Institute, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Xingxu Yan
- Department
of Materials Science and Engineering, University
of California, Irvine, Irvine, California 92697, United States
| | - Vayle Vera Cruz
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Melanie Weed
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Jackie Johnson
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Gonto Johns
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
| | - Gary W. Brudvig
- Department
of Chemistry and Yale Energy Sciences Institute, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Xiaoqing Pan
- Department
of Materials Science and Engineering, University
of California, Irvine, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, Irvine, California 92697, United States
| | - Jing Gu
- Department
of Chemistry and Biochemistry, San Diego
State University, 5500 Campanile Drive, San Diego, California 92182, United States
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Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS. NANOMATERIALS 2021; 12:nano12010043. [PMID: 35009993 PMCID: PMC8747037 DOI: 10.3390/nano12010043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 01/15/2023]
Abstract
The wafer-scale integration of graphene is of great importance in view of its numerous applications proposed or underway. A good graphene–silicon interface requires the fine control of several parameters and may turn into a high-cost material, suitable for the most advanced applications. Procedures that can be of great use for a wide range of applications are already available, but others are to be found, in order to modulate the offer of different types of materials, at different levels of sophistication and use. We have been exploring different electrochemical approaches over the last 5 years, starting from graphene oxide and resulting in graphene deposited on silicon-oriented surfaces, with the aim of understanding the reactions leading to the re-establishment of the graphene network. Here, we report how a proper choice of both the chemical environment and electrochemical conditions can lead to a more controlled and tunable graphene–Si(111) interface. This can also lead to a deeper understanding of the electrochemical reactions involved in the evolution of graphene oxide to graphene under electrochemical reduction. Results from XPS, the most suitable tool to follow the presence and fate of functional groups at the graphene surface, are reported, together with electrochemical and Raman findings.
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A Novel N-Doped Nanoporous Bio-Graphene Synthesized from Pistacia lentiscus Gum and Its Nanocomposite with WO 3 Nanoparticles: Visible-Light-Driven Photocatalytic Activity. Molecules 2021; 26:molecules26216569. [PMID: 34770977 PMCID: PMC8588091 DOI: 10.3390/molecules26216569] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
This paper reports the synthesis of a new nitrogen-doped porous bio-graphene (NPBG) with a specific biomorphic structure, using Pistacia lentiscus as a natural carbon source containing nitrogen that also acts as a bio-template. The obtained NPBG demonstrated the unique feature of doped nitrogen with a 3D nanoporous structure. Next, a WO3/N-doped porous bio-graphene nanocomposite (WO3/NPBG-NC) was synthesized, and the products were characterized using XPS, SEM, TEM, FT-IR, EDX, XRD, and Raman analyses. The presence of nitrogen doped in the structure of the bio-graphene (BG) was confirmed to be pyridinic-N and pyrrolic-N with N1 peaks at 398.3 eV and 400.5 eV, respectively. The photocatalytic degradation of the anionic azo dyes and drugs was investigated, and the results indicated that the obtained NPBG with a high surface area (151.98 m2/g), unique electronic properties, and modified surface improved the adsorption and photocatalytic properties in combination with WO3 nanoparticles (WO3-NPs) as an effective visible-light-driven photocatalyst. The synthesized WO3/NPBG-NC with a surface area of 226.92 m2/g displayed lower bandgap and higher electron transfer compared with blank WO3-NPs, leading to an increase in the photocatalytic performance through the enhancement of the separation of charge and a reduction in the recombination rate. At the optimum conditions of 0.015 g of the nanocomposite, a contact time of 15 min, and 100 mg/L of dyes, the removal percentages were 100%, 99.8%, and 98% for methyl red (MR), Congo red (CR), and methyl orange (MO), respectively. In the case of the drugs, 99% and 87% of tetracycline and acetaminophen, respectively, at a concentration of 10 mg/L, were removed after 20 min.
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Kubota W, Utsunomiya T, Ichii T, Sugimura H. Chemical Etching of Silicon Assisted by Graphene Oxide in an HF-HNO 3 Solution and Its Catalytic Mechanism. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9920-9926. [PMID: 34351164 DOI: 10.1021/acs.langmuir.1c01681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Chemical etching of silicon assisted by various types of carbon materials is drawing much attention for the fabrication of silicon micro/nanostructures. We developed a method of chemical etching of silicon that utilizes graphene oxide (GO) sheets to promote the etching reaction in a hydrofluoric acid-nitric acid (HF-HNO3) etchant. By using an optimized composition of the HF-HNO3 etchant, the etching rate under the GO sheets was 100 times faster than that of our HF-H2O2 system used in a previous report. Kinetic analyses showed that the activation energy of the etching reaction was almost the same at both the bare silicon and GO-covered areas. We propose that adsorption sites for the reactant in the GO sheets enhance the reaction frequency, leading to a deeper etching in the GO areas than the bare areas. Furthermore, GO sheets with more defects were found to have higher catalytic activities. This suggests that defects in the GO sheets function as adsorption sites for the reactant, thereby enhancing the etching rate under the sheets.
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Affiliation(s)
- Wataru Kubota
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Toru Utsunomiya
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Takashi Ichii
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
| | - Hiroyuki Sugimura
- Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan
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Ke J, Zhou H, Liu J, Zhang Z, Duan X, Wang S. Enhanced light-driven water splitting by fast electron transfer in 2D/2D reduced graphene oxide/tungsten trioxide heterojunction with preferential facets. J Colloid Interface Sci 2019; 555:413-422. [DOI: 10.1016/j.jcis.2019.08.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/03/2019] [Accepted: 08/02/2019] [Indexed: 01/13/2023]
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Yu K, Takara Y, Tu Y, Utsunomiya T, Ichii T, Sugimura H. Chemical Immobilization of Graphene Oxide on Hydrogen Terminated Silicon via Vinyl Aniline Molecule Linking. CHEM LETT 2019. [DOI: 10.1246/cl.190398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kunhua Yu
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuya Takara
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yudi Tu
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Toru Utsunomiya
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takashi Ichii
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroyuki Sugimura
- Department of Materials Science and Engineering, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
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