scholarly journals Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 179
Author(s):  
Phuong Anh Nguyen ◽  
Thi Kim Anh Nguyen ◽  
Duc Quang Dao ◽  
Eun Woo Shin
Keyword(s):  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Electrochemical Impedance ◽  
Hydrogen Desorption ◽  
Solvothermal Treatment ◽  
Efficient Charge ◽  
Different Temperatures ◽  
Electrochemical Impedance Spectroscopy Data ◽  
First Time ◽  
Carbon Nitride Materials

Recently, Pt-loaded graphic carbon nitride (g-C3N4) materials have attracted great attention as a photocatalyst for hydrogen evolution from water. The simple surface modification of g-C3N4 by hydrothermal methods improves photocatalytic performance. In this study, ethanol is used as a solvothermal solvent to modify the surface properties of g-C3N4 for the first time. The g-C3N4 is thermally treated in ethanol at different temperatures (T = 140 °C, 160 °C, 180 °C, and 220 °C), and the Pt co-catalyst is subsequently deposited on the g-C3N4 via a photodeposition method. Elemental analysis and XPS O 1s data confirm that the ethanol solvothermal treatment increased the contents of the oxygen-containing functional groups on the g-C3N4 and were proportional to the treatment temperatures. However, the XPS Pt 4f data show that the Pt2+/Pt0 value for the Pt/g-C3N4 treated at ethanol solvothermal temperature of 160 °C (Pt/CN-160) is the highest at 7.03, implying the highest hydrogen production rate of Pt/CN-160 is at 492.3 μmol g−1 h−1 because the PtO phase is favorable for the water adsorption and hydrogen desorption in the hydrogen evolution process. In addition, the electrochemical impedance spectroscopy data and the photoluminescence spectra emission peak intensify reflect that the Pt/CN-160 had a more efficient charge separation process that also enhanced the photocatalytic activity.

Facile synthesis of tin-doped polymeric carbon nitride with a hole-trapping center for efficient charge separation and photocatalytic hydrogen evolution

2019 ◽  
Vol 7 (45) ◽  
pp. 25824-25829 ◽  
Author(s):  
Zhiwei Liang ◽  
Yuguo Xia ◽  
Guiming Ba ◽  
Haiping Li ◽  
Quanhua Deng ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Charge Separation ◽  
Carbon Nitride ◽  
Facile Synthesis ◽  
Photocatalytic Hydrogen Evolution ◽  
Hole Capture ◽  
Hole Trapping ◽  
Efficient Charge ◽  
Polymeric Carbon ◽  
First Time

For the first time, Sn-doped polymeric carbon nitride was synthesized with N–Sn bonds working as hole-capture centers for enhanced photocatalytic hydrogen evolution.

scholarly journals Solar Energy Harvesting with Carbon Nitrides: Do We Understand the Mechanism?

2018 ◽  
Author(s):  
Wolfgang Domcke ◽  
Johannes Ehrmaier ◽  
Andrzej L. Sobolewski
Keyword(s):  
Excited State ◽  
Solar Energy ◽  
Water Molecule ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydroxyl Radicals ◽  
Carbon Nitride ◽  
Carbon Nitrides ◽  
Polymeric Carbon ◽  
Carbon Nitride Materials

The photocatalytic splitting of water into molecular hydrogen and molecular oxygen with sunlight is the dream reaction for solar energy conversion. Since decades, transition-metal-oxide semiconductors and supramolecular organometallic structures have been extensively explored as photocatalysts for solar water splitting. More recently, polymeric carbon nitride materials consisting of triazine or heptazine building blocks have attracted considerable attention as hydrogen-evolution photocatalysts. The mechanism of hydrogen evolution with polymeric carbon nitrides is discussed throughout the current literature in terms of the familiar concepts developed for photoelectrochemical water splitting with semiconductors since the 1970s. We discuss in this perspective an alternative mechanistic paradigm for photoinduced water splitting with carbon nitrides, which focusses on the specific features of the photochemistry of aromatic N-heterocycles in aqueous environments. It is shown that a water molecule which is hydrogen-bonded to an N-heterocycle can be decomposed into hydrogen and hydroxyl radicals by two simple sequential photochemical reactions. This concept is illustrated by first-principles calculations of excited-state reaction paths and their energy profiles for hydrogen-bonded complexes of pyridine, triazine and heptazine with a water molecule. It is shown that the excited-state hydrogen-transfer and hydrogen-detachment reactions are essentially barrierless, in sharp contrast to water oxidation in the electronic ground state, where high barriers prevail. We also discuss in some detail the products of possible reactions of the highly reactive hydroxyl radicals with the chromophores. We hypothesize that the challenge of efficient solar hydrogen generation with carbon-nitride materials is less the decomposition of water as such, but rather the controlled recombination of the photogenerated radicals to the closed-shell products H2 and H2O2.

3D reticulated carbon nitride materials high-uniformly capture 0D black phosphorus as 3D/0D composites for stable and efficient photocatalytic hydrogen evolution

2019 ◽  
Vol 7 (2) ◽  
pp. 503-512 ◽  
Author(s):  
Ting Song ◽  
Gongchang Zeng ◽  
Piyong Zhang ◽  
Tingting Wang ◽  
Atif Ali ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Black Phosphorus ◽  
The Self ◽  
Photocatalytic Hydrogen Evolution ◽  
Carbon Nitride Materials

A facile strategy to fabricate a uniform 3D/0D hybrid as a stable and excellent photocatalyst utilizing the self-capturing property of CN-4N.

Platinum-complexed phosphorous-doped carbon nitride for electrocatalytic hydrogen evolution

2021 ◽  
Author(s):  
Forrest Nichols ◽  
Qiming Liu ◽  
Jasleen Sandhu ◽  
Zahra Azhar ◽  
Rafael Cazares ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Thermal Annealing ◽  
Carbon Nitride ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Carbon Nitride Materials ◽  
Ammonium Hexafluorophosphate

Sustainable hydrogen gas production is critical for future fuel infrastructure. Here, a series of phosphorous-doped carbon nitride materials were synthesized by thermal annealing of urea and ammonium hexafluorophosphate, and platinum...

Highly active g-C3N4 photocatalysts modified with transition metal cobalt for hydrogen evolution

2021 ◽  
Author(s):  
Juan Xie ◽  
Chenjie Wang ◽  
Ning Chen ◽  
Weifeng Chen ◽  
Jiake Xu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Transition Metal ◽  
Hydrogen Evolution ◽  
Structural Engineering ◽  
Carbon Nitride ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Hydrogen Production ◽  
Challenging Issue ◽  
Highly Active ◽  
First Time

Developing highly effective photocatalytic hydrogen production in graphitic carbon nitride (g-C3N4) is still a challenging issue. Herein, for the first time, the structural engineering of g-C3N4 nanosheets with Co atoms...

scholarly journals The importance of using hydrogen evolution inhibitor during the Zn and Zn-Mn electrodeposition from ethaline

2019 ◽  
Vol 84 (11) ◽  
pp. 1221-1234 ◽  
Author(s):  
Mihael Bucko ◽  
Milorad Tomic ◽  
Miodrag Maksimovic ◽  
Jelena Bajat
Keyword(s):  
Hydrogen Evolution ◽  
Electrochemical Impedance ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Corrosion Stability ◽  
Zinc Electrodeposition ◽  
Current Densities ◽  
The Stability ◽  
First Time

Cyclic voltammetry was used for the characterization of zinc electrodeposition on steel from ethaline deep eutectic solution (1:2 choline chloride: ethylene glycol). The influence of 4-hydroxy-benzaldehyde (HBA) as an additive was analyzed. It was shown that hydrogen evolution is inhibited in the presence of HBA and further significantly retarded upon addition of Zn2+ to the solution containing HBA. The cathodic peak for Zn2+ reduction in this type of ionic liquid (ethaline+HBA+Zn2+) resembles the zinc reduction in aqueous solution. The corrosion resistance of Zn coatings deposited at different current densities was evaluated by electrochemical methods, i.e., polarization measurements and electrochemical impedance spectroscopy in 3 % NaCl solution. The possibility of Zn?Mn alloy deposition from ethaline deep eutectic solvent was investigated for the first time. In addition, the corrosion stability of these alloy coatings was analyzed and compared to the stability of bare Zn coatings. It was shown that the optimum deposition current density for both Zn and Zn?Mn coatings with increased corrosion stability from ethaline + HBA electrolyte is 5 mA cm?2.

scholarly journals Solar Energy Harvesting with Carbon Nitrides: Do We Understand the Mechanism?

2018 ◽  
Author(s):  
Wolfgang Domcke ◽  
Johannes Ehrmaier ◽  
Andrzej L. Sobolewski
Keyword(s):  
Excited State ◽  
Solar Energy ◽  
Water Molecule ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydroxyl Radicals ◽  
Carbon Nitride ◽  
Carbon Nitrides ◽  
Polymeric Carbon ◽  
Carbon Nitride Materials

The photocatalytic splitting of water into molecular hydrogen and molecular oxygen with sunlight is the dream reaction for solar energy conversion. Since decades, transition-metal-oxide semiconductors and supramolecular organometallic structures have been extensively explored as photocatalysts for solar water splitting. More recently, polymeric carbon nitride materials consisting of triazine or heptazine building blocks have attracted considerable attention as hydrogen-evolution photocatalysts. The mechanism of hydrogen evolution with polymeric carbon nitrides is discussed throughout the current literature in terms of the familiar concepts developed for photoelectrochemical water splitting with semiconductors since the 1970s. We discuss in this perspective an alternative mechanistic paradigm for photoinduced water splitting with carbon nitrides, which focusses on the specific features of the photochemistry of aromatic N-heterocycles in aqueous environments. It is shown that a water molecule which is hydrogen-bonded to an N-heterocycle can be decomposed into hydrogen and hydroxyl radicals by two simple sequential photochemical reactions. This concept is illustrated by first-principles calculations of excited-state reaction paths and their energy profiles for hydrogen-bonded complexes of pyridine, triazine and heptazine with a water molecule. It is shown that the excited-state hydrogen-transfer and hydrogen-detachment reactions are essentially barrierless, in sharp contrast to water oxidation in the electronic ground state, where high barriers prevail. We also discuss in some detail the products of possible reactions of the highly reactive hydroxyl radicals with the chromophores. We hypothesize that the challenge of efficient solar hydrogen generation with carbon-nitride materials is less the decomposition of water as such, but rather the controlled recombination of the photogenerated radicals to the closed-shell products H2 and H2O2.

scholarly journals Photodoping and Fast Charge Extraction in Ionic Carbon Nitride Photoanodes

2021 ◽  
Author(s):  
Christiane Adler ◽  
Shababa Selim ◽  
Igor Krivtsov ◽  
Chunyu Li ◽  
Dariusz Mitoraj ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Zero Bias ◽  
Oxide Semiconductors ◽  
Binder Free ◽  
First Time ◽  
Kinetics Of ◽  
Shed Light ◽  
Carbon Nitride Materials ◽  
Absorption Measurements ◽  
Electron Extraction

<p>Ionic carbon nitrides based on poly(heptazine imides) (PHI) represent a vigorously studied class of materials with possible applications in photocatalysis and energy storage. Herein, we study, for the first time, the photogenerated charge dynamics in highly stable and binder-free PHI photoanodes using <i>in operando</i> transient photocurrents and spectroelectrochemical photoinduced absorption measurements. We discover that light-induced accumulation of long-lived trapped electrons within the PHI film leads to effective photodoping of the PHI film, resulting in a significant improvement of photocurrent response due to more efficient electron transport. While photodoping has been previously reported for various semiconductors, it has never been shown before for carbon nitride materials. Furthermore, we find that the extraction kinetics of untrapped electrons are remarkably fast in these PHI photoanodes, with electron extraction times (ms) comparable to those measured for commonly employed metal oxide semiconductors. These results shed light on the excellent performance of PHI photoanodes in alcohol photoreforming, including very negative photocurrent onset, outstanding fill factor, and the possibility to operate under zero-bias conditions. More generally, the here reported photodoping effect and fast electron extraction in PHI photoanodes establish a strong rationale for the use of PHI films in various applications, such as bias-free photoelectrochemistry or photobatteries.<br></p>

Soft-template induced synthesis of high-crystalline polymeric carbon nitride with boosted photocatalytic performance

2021 ◽  
Vol 9 (11) ◽  
pp. 6805-6810
Author(s):  
Zhiwei Liang ◽  
Xiaojia Zhuang ◽  
Zicheng Tang ◽  
Haiping Li ◽  
Lei Liu ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Soft Template ◽  
Photocatalytic Hydrogen Evolution ◽  
Induction Strategy ◽  
Polymeric Carbon ◽  
First Time ◽  
Enhanced Crystallinity

A soft-template induction strategy is reported for the first time to synthesize polymeric carbon nitride with remarkably enhanced crystallinity and photocatalytic hydrogen evolution.

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