Unveiling the role of a ground state charge transfer complex in carbon nanoparticles for highly efficient metal-free solar hydrogen production

Kar, Subhajit; Kumar, Amit; Mandal, Ramesh; Chawla, Sakshi; Patra, Shanti Gopal; De, Arijit K.; Bhattacharyya, Santanu

doi:10.1039/d3ta07895g

Cited by 3 publications

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“…As a result, the photocatalytic hydrogen generation activities of FTz are enhanced due to an improved charge transfer process. The presence of a positive slope in the Mott–Schotky analysis offers further support for the n-type properties displayed by all of these one-dimensional polymers (Figure c). ,, Fermi level potentials ( E fb ) for PhTz , ClTz , and FTz were determined using extrapolation of the Mott–Schottky plot, where the inverse of the square of the capacitance (1/C 2 ) was set to zero. The values of E fb for all of the 1D polymers were found to be between −0.60 and 0.15 V (Figure d).…”

Section: Resultsmentioning

confidence: 67%

“…The above factors play an important role in boosting the photocatalytic activities, which explains the high photocatalytic activity of FTz . Moreover, the anodic current production in photocurrent response shows that all of these polymers exhibit n-type semiconductor behavior (Figure b). − The prevalence of n-type semiconductors is more pronounced in FTz compared to ClTz and PhTz , possibly due to the integration of higher electronegative fluorine atoms in FTz . The declining and least photocurrent behavior of pristine PhTz shows their insufficient long-term free carriers and, thus, poor photocatalytic activity.…”

Section: Resultsmentioning

confidence: 99%

“…The charge transfer process at the interface of all of the polymers has been revealed by the utilization of EIS and Mott–Schottky analysis. The Nyquist plot (EIS) shows that the arc radius for FTz is significantly smaller than ClTz and PhTz , suggesting a reduced electron resistance or enhanced charge transfer process , at the interface of FTz (Figure c). As a result, the photocatalytic hydrogen generation activities of FTz are enhanced due to an improved charge transfer process.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Kar,

Bhattacharyya

et al. 2024

ACS Appl. Polym. Mater.

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Developing highly efficient photocatalysts for water splitting is crucial in the conversion of solar energy into hydrogen. Improving the catalytic performance via substituents optimization on the photocatalyst is a desirable technique, as it requires minimum changes to its structure. In this study, we showcase the impact of halogenation on the efficiency of tetrazine-integrated 1D linear polymers in generating hydrogen using photocatalysis. This work utilizes three copolymers (PhTz, FTz, and ClTz) synthesized by the Pinner process, employing tetrazine and phenylene/tetrafluorophenylene/tetrachlorophenylene, respectively. The polymers have a πconjugated backbone and display significant absorption in the visible spectrum with an absorption red edge within the wavelength range of 820−640 nm with optical band gaps ranging from 1.51 to 1.94 eV. The photocatalytic hydrogen evolution of these polymers under metal-free conditions has revealed that the fluorine-substituted polymer (FTz) exhibited a significantly higher performance of 227 μmol g −1 h −1 , which is twice as high as that of ClTz (116.6 μmol g −1 h −1 ) and five times higher than that of the nonhalogenated polymer (PhTz) (46.2 μmol g −1 h −1 ). The presence of halogens substantially lowered the energy barrier for hydrogen adsorption on the polymer surface: ΔG°values for FTz, ClTz, and PhTz are 0.07, 0.11, and 0.19 eV, respectively. On the other hand, tetrazine is crucial for reducing the energy bandgap, augmenting the absorption of visible light, and facilitating the binding of hydrogen atoms.

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Section: Resultsmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Kar,

Bhattacharyya

et al. 2024

ACS Appl. Polym. Mater.

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Integrating a Dual Mode of Intrinsic Structural Modifications of g-C₃N₄ by K⁺ Ions and Amorphous Carbon for Efficient Photocatalytic H₂O₂ Production

Mandal,

Bhattacharyya

2024

J. Phys. Chem. C

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Herein, a dual mode of intrinsic structural modifications of g-C 3 N 4 has been designed by simultaneous incorporations of alkali metal K + and amorphous carbon inside the 2D matrix of g-C 3 N 4 . Detailed structural and elemental investigations suggest that this typical dual mode of structural modifications promotes intraband defects, porosity, and active sites for photocatalysis. The optoelectronic features of the structurally modified g-C 3 N 4 are further supported by the in-depth photophysical studies. Results suggest that visible light absorption increases along with efficient charge separation inside g-C 3 N 4 , upon simultaneous incorporation of K + and amorphous carbon. Finally, this typical structurally modified g-C 3 N 4 system has been utilized for photocatalytic H 2 O 2 production. The maximum H 2 O 2 production reaches up to 9000 μmol g catalyst −1 h −1 with ∼30% apparent quantum efficiency. The mechanism of this highly efficient photocatalytic H 2 O 2 production has been studied by investigating the intermediates and photoinduced active species through chemical scavenging and electron paramagnetic resonance spectroscopy. Results show the crucial role of photoinduced oxygen free radicals in photocatalytic H 2 O 2 production. This high value of H 2 O 2 production efficiency upon application of the dual mode of structural modifications of g-C 3 N 4 systems has been further supported by detailed transient photocurrent studies and electrochemical impedance spectroscopy.

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Role of Trap Optimization in a Heterostructure Carbon Nitride as a Methodology to Enhance Photocatalytic Hydrogen Production

Saha,

Mandal,

Wadepalli

et al. 2024

J. Phys. Chem. Lett.

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Carbon-based catalysts hold significant promise for photocatalytic hydrogen evolution. A critical challenge lies in optimizing the balance between electron longevity and its accumulation to avoid bottlenecks in photocatalytic efficiency. In this study, we introduce an innovative and efficient strategy for the rapid extraction (<100 fs) of photoinduced free electrons from a carbon-based catalyst without forming additional metal-based heterojunction hybrids. This method effectively prevents excessive accumulation of free carriers within the catalyst. The rapidly extracted electrons are then utilized for photocatalytic hydrogen production, resulting in a 10-fold increase in activity compared to the pristine catalyst, with platinum (3 wt%) used as a cocatalyst. Our strategy significantly enhances the performance of a state-of-the-art catalyst, offering a clean and cost-effective method for producing clean energy. This work demonstrates how a fundamental understanding of molecular-level phenomena and their optimization can pave the way for delivering clean and affordable energy to society.

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Unveiling the role of a ground state charge transfer complex in carbon nanoparticles for highly efficient metal-free solar hydrogen production

Abstract: Carbon-based nanoparticles (CNPs) are exciting metal-free photocatalysts for solar hydrogen production. However, significant challenges remain in elucidating their complex structures and identifying the potential catalytic sites. Herein, a specific ground-state...

Cited by 3 publications

References 75 publications

Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Integrating a Dual Mode of Intrinsic Structural Modifications of g-C₃N₄ by K⁺ Ions and Amorphous Carbon for Efficient Photocatalytic H₂O₂ Production

Role of Trap Optimization in a Heterostructure Carbon Nitride as a Methodology to Enhance Photocatalytic Hydrogen Production

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Unveiling the role of a ground state charge transfer complex in carbon nanoparticles for highly efficient metal-free solar hydrogen production

Abstract: Carbon-based nanoparticles (CNPs) are exciting metal-free photocatalysts for solar hydrogen production. However, significant challenges remain in elucidating their complex structures and identifying the potential catalytic sites. Herein, a specific ground-state...

Cited by 3 publications

References 75 publications

Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Effect of Halogenation on the Photocatalytic Hydrogen Evolution Performance of Tetrazine Polymers

Integrating a Dual Mode of Intrinsic Structural Modifications of g-C3N4 by K+ Ions and Amorphous Carbon for Efficient Photocatalytic H2O2 Production

Role of Trap Optimization in a Heterostructure Carbon Nitride as a Methodology to Enhance Photocatalytic Hydrogen Production

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Integrating a Dual Mode of Intrinsic Structural Modifications of g-C₃N₄ by K⁺ Ions and Amorphous Carbon for Efficient Photocatalytic H₂O₂ Production