Regulating morphological and electronic structures of polymeric carbon nitrides by successive copolymerization and stream reforming for photocatalytic CO2 reduction

2021 ◽  
Author(s):  
Ruirui Wang ◽  
Pengju Yang ◽  
Sibo Wang ◽  
Xinchen Wang
Keyword(s):  
Electronic Structures ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Carbon Nitrides ◽  
Polymeric Carbon

Greatly reinforced photocatalytic CO2 reduction is realized with carbon nitride polymers tailored via a coupled copolymerization and stream reforming strategy.

scholarly journals Tailoring the Grain Boundary Chemistry of Polymeric Carbon Nitride for Enhanced Solar Hydrogen Production and CO2 Reduction

2019 ◽  
Vol 131 (11) ◽  
pp. 3471-3475 ◽  
Author(s):  
Guigang Zhang ◽  
Guosheng Li ◽  
Tobias Heil ◽  
Spiros Zafeiratos ◽  
Feili Lai ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Grain Boundary ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production ◽  
Boundary Chemistry ◽  
Polymeric Carbon

scholarly journals Conjugated Electron Donor–Acceptor Hybrid Polymeric Carbon Nitride as a Photocatalyst for CO2 Reduction

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1779 ◽  
Author(s):  
Asif Hayat ◽  
Mati Ur Rahman ◽  
Iltaf Khan ◽  
Javid Khan ◽  
Muhammad Sohail ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Molecular Orbital ◽  
Density Functional ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Characterization Methods ◽  
Base Functions ◽  
Activity Performance ◽  
Donor Acceptor ◽  
Polymeric Carbon

This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor–acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid–base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H2 from CO2 by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.

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.

Edge activation of an inert polymeric carbon nitride matrix with boosted absorption kinetics and near-infrared response for efficient photocatalytic CO2 reduction

2020 ◽  
Vol 8 (23) ◽  
pp. 11761-11772 ◽  
Author(s):  
Qiong Liu ◽  
Zhongxin Chen ◽  
Weijian Tao ◽  
Haiming Zhu ◽  
Linxin Zhong ◽  
...  
Keyword(s):  
Activation Energy ◽  
Energy Barrier ◽  
Carbon Nitride ◽  
Near Infrared ◽  
Co2 Reduction ◽  
Absorption Capacity ◽  
Absorption Kinetics ◽  
Activation Energy Barrier ◽  
Polymeric Carbon

The edge-activation of the polymeric carbon nitride matrix by hydroxyethyl groups results in enhanced CO2 absorption capacity and decrease in the CO2 activation energy barrier.

scholarly journals Pyrene-functionalized polymeric carbon nitride with promoted aqueous–organic biphasic photocatalytic CO2 reduction

2019 ◽  
Vol 7 (13) ◽  
pp. 7373-7379 ◽  
Author(s):  
Xuezhong Gong ◽  
Sijia Yu ◽  
Meili Guan ◽  
Xianglin Zhu ◽  
Can Xue
Keyword(s):  
Aqueous Solution ◽  
Organic Phase ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Alkene Oxidation ◽  
Polymeric Carbon

Covalently grafting pyrene groups on polymeric carbon nitride enables photocatalytic CO2 reduction in aqueous solution with simultaneous alkene oxidation in organic phase.

scholarly journals FeP modified polymeric carbon nitride as a noble-metal-free photocatalyst for efficient CO2 reduction

2021 ◽  
pp. 106326
Author(s):  
Yangkun Guo ◽  
Qiang Wang ◽  
Min Wang ◽  
Meng Shen ◽  
Lingxia Zhang ◽  
...  
Keyword(s):  
Noble Metal ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Metal Free ◽  
Polymeric Carbon
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