scholarly journals Conductivity mechanism in ionic 2D carbon nitrides: from hydrated ion motion to enhanced photocatalysis

2021 ◽  
Author(s):  
Julia Kröger ◽  
Filip Podjaski ◽  
Gökçen Savaşçı ◽  
Igor Moudrakovski ◽  
Alberto Jimenez-Solano ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Ionic Conductivity ◽  
Charge Carrier ◽  
Pore Channel ◽  
Ion Motion ◽  
Carrier Lifetimes ◽  
Carbon Nitrides ◽  
Efficient Charge ◽  
Mobile Ions ◽  
Hydrated Ion

Carbon nitrides are among the most studied materials for photocatalysis, however, limitations arise from inefficient charge separation and transport within the material. Here, this aspect is addressed in the 2D carbon nitride poly(heptazine imide) (PHI) by investigating the influence of various counterions, such as M = Li+, Na+, K+, Cs+, Ba2+, NH4+ and tetramethyl ammonium, on the material’s conductivity and photocatalytic activity. These ions in the PHI pores affect the stacking of the 2D layers, which further influences the predominantly ionic conductivity in M-PHI. Na-containing PHI outperforms the other M-PHI in various relative humidity (RH) environments (0-42 %RH) in terms of conductivity, likely due to pore channel geometry and size of the (hydrated) ion. With increasing RH, the ionic conductivity increases by 4-5 orders of magnitude (for Na-PHI up to 10-5 S cm-1 at 42 %RH). At the same time, the highest photocatalytic hydrogen evolution rate is observed for Na-PHI, which is mirrored by increased photo-generated charge carrier lifetimes, pointing to efficient charge carrier stabilization by mobile ions. These results indicate that ionic conductivity is an important parameter that can influence the photocatalytic activity. Besides, RH-dependent ionic conductivity is of high interest for separators, membranes, or sensors.

scholarly journals Understanding the visible-light photocatalytic activity of GaN:ZnO solid solution: the role of Rh2−yCryO3 cocatalyst and charge carrier lifetimes over tens of seconds

2018 ◽  
Vol 9 (38) ◽  
pp. 7546-7555 ◽  
Author(s):  
Robert Godin ◽  
Takashi Hisatomi ◽  
Kazunari Domen ◽  
James R. Durrant
Keyword(s):  
Solid Solution ◽  
Photocatalytic Activity ◽  
Charge Carrier ◽  
Water Oxidation ◽  
Carrier Lifetime ◽  
Time Resolved ◽  
Carrier Lifetimes ◽  
Charge Carrier Lifetime ◽  
Visible Light Photocatalytic

Time-resolved spectroscopies reveals remarkably long charge carrier lifetime in GaN:ZnO solid solution leading to hole accumulation key to water oxidation.

scholarly journals Conductivity mechanism in ionic 2D carbon nitrides: from hydrated ion motion to enhanced photocatalysis

2021 ◽  
pp. 2107061
Author(s):  
Julia Kröger ◽  
Filip Podjaski ◽  
Gökcen Savasci ◽  
Igor Moudrakovski ◽  
Alberto Jimenez‐Solano ◽  
...  
Keyword(s):  
Ion Motion ◽  
Conductivity Mechanism ◽  
Carbon Nitrides ◽  
Hydrated Ion

scholarly journals Dynamic switching of ionic conductivity by cooperative interaction of polyviologen and liquid crystals for efficient charge storage

2016 ◽  
Vol 4 (9) ◽  
pp. 3249-3252 ◽  
Author(s):  
Kan Sato ◽  
Takaaki Yamasaki ◽  
Takahiro Mizuma ◽  
Kenichi Oyaizu ◽  
Hiroyuki Nishide
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Ionic Conductivity ◽  
Redox Reactions ◽  
Cooperative Interaction ◽  
Charge Storage ◽  
Dynamic Switching ◽  
Efficient Charge

The ionic conductivity of a liquid crystal electrolyte was switched along with redox reactions of polyviologen.

scholarly journals Facile Preparation of Efficient WO3Photocatalysts Based on Surface Modification

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Min Liu ◽  
Hongmei Li ◽  
Yangsu Zeng
Keyword(s):  
Photocatalytic Activity ◽  
Surface Modification ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Impregnation Method ◽  
Light Spectra ◽  
Simple Strategy ◽  
Visible Light Active ◽  
Efficient Charge ◽  
Surface Modified

Tungsten trioxide (WO3) was surface modified with Cu(II) nanoclusters and titanium dioxide (TiO2) nanopowders by using a simple impregnation method followed by a physical combining method. The obtained nanocomposites were studied by scanning electron microscope, X-ray photoelectron spectroscopy spectra, UV-visible light spectra, and photoluminescence, respectively. Although the photocatalytic activity of WO3was negligible under visible light irradiation, the visible light photocatalytic activity of WO3was drastically enhanced by surface modification of Cu(II) nanoclusters and TiO2nanopowders. The enhanced photocatalytic activity is due to the efficient charge separation by TiO2and Cu(II) nanoclusters functioning as cocatalysts on the surface. Thus, this simple strategy provides a facile route to prepare efficient visible-light-active photocatalysts for practical application.

Enhancement of the Photocatalytic Activity of Carbon Nitrides by Complex Templating

2015 ◽  
Vol 21 (30) ◽  
pp. 10805-10811 ◽  
Author(s):  
Zu Peng Chen ◽  
Markus Antonietti ◽  
Dariya Dontsova
Keyword(s):  
Photocatalytic Activity ◽  
Carbon Nitrides

Greatly enhanced photocatalytic activity by organic flexible piezoelectric PVDF induced spatial electric field

2017 ◽  
Vol 7 (23) ◽  
pp. 5594-5601 ◽  
Author(s):  
Baoying Dai ◽  
Hengming Huang ◽  
Wei Wang ◽  
Yukai Chen ◽  
Chunhua Lu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Electric Field ◽  
Charge Separation ◽  
High Photocatalytic Activity ◽  
Efficient Charge ◽  
Vital Factor

Efficient charge separation accelerated by a spatial electric field is a vital factor for semiconductor photocatalysts to achieve high photocatalytic activity.

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