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...

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.

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 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.

Tuning of the Oxygen Species Linker on the Surface of Polymeric Carbon Nitride to Promote the Photocatalytic Hydrogen Evolution Performance

ChemSusChem ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3605-3613 ◽  
Author(s):  
Qin Lei ◽  
Rongzhi Chen ◽  
Yurong Zhao ◽  
Huanyu Chen ◽  
Xinxin Long ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Oxygen Species ◽  
Photocatalytic Hydrogen Evolution ◽  
Polymeric Carbon

Cobalt ion redox and conductive polymers boosted the photocatalytic activity of the graphite carbon nitride–Co3O4 Z-scheme heterostructure

2021 ◽  
Vol 45 (1) ◽  
pp. 162-168
Author(s):  
Tao Li ◽  
Jiandong Cui ◽  
Yezhan Lin ◽  
Kecheng Liu ◽  
Rui Li ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Synergistic Effect ◽  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Conductive Polymers ◽  
Cobalt Ion ◽  
Photocatalytic Hydrogen Evolution ◽  
Conductive Polyaniline

The enhanced photocatalytic hydrogen evolution performance of g-C3N4–Co3O4 2D–1D Z-scheme heterojunctions was achieved through the synergistic effect of the cobalt ion redox, conductive polyaniline, and a Co3O4 nanobelt.

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