scholarly journals Mechanistic analysis of multiple processes controlling solar-driven H2O2 synthesis using engineered polymeric carbon nitride

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yubao Zhao ◽  
Peng Zhang ◽  
Zhenchun Yang ◽  
Lina Li ◽  
Jingyu Gao ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Separation Efficiency ◽  
Structural Features ◽  
Reduction Reaction ◽  
Transformation Process ◽  
Photon Absorption ◽  
Apparent Quantum Yield ◽  
Dioxygen Reduction ◽  
Polymeric Carbon

AbstractSolar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride framework with sodium cyanaminate moiety, affording a H2O2 production rate of 18.7 μmol h −1 mg−1 and an apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed, and some previously unknown structural features and interactions are substantiated via experimental and theoretical methods. The structural features of cyanamino group and pyridinic nitrogen-coordinated soidum in the framework promote photon absorption, alter the energy landscape of the framework and improve charge separation efficiency, enhance surface adsorption of dioxygen, and create selective 2e− oxygen reduction reaction surface-active sites. Particularly, an electronic coupling interaction between O2 and surface, which boosts the population and prolongs the lifetime of the active shallow-trapped electrons, is experimentally substantiated.

scholarly journals Identification and Analysis of Multiple Factors Controlling Solar-driven H2O2 Synthesis Using Engineered Polymeric Carbon Nitride

2020 ◽  
Author(s):  
Yubao Zhao ◽  
Jingyu Gao ◽  
Lina Li ◽  
Sheng Chen ◽  
Chun Hu ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Reduction Process ◽  
Transformation Process ◽  
Photon Absorption ◽  
Apparent Quantum Yield ◽  
Environmental Friendliness ◽  
Dioxygen Reduction ◽  
Time Regime ◽  
P Type ◽  
Polymeric Carbon

Abstract Solar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, highly efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride (PCN) framework with sodium cyanaminate moiety (PCN-NaCA), affording a superior H2O2 production rate of 175 μmol/h on 10 mg photocatalyst and a notable apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed using various steady-state/transient spectroscopic and computational methods. The presence of sodium cyanaminate moiety in PCN-NaCA induces the following multiple effects: enhancing photon absorption, creating the coexistence of p-type and n-type domains, strengthening surface adsorption of dioxygen, and favoring highly selective 2e− ORR. In particular, the adsorption of dioxygen on PCN-NaCA enhances the population and lifetime of trapped electrons in the ps-ns time regime, which should have a notable synergic effect on oxygen reduction process.

Enhanced photocatalytic hydrogen production from aqueous-phase methanol reforming over cyano-carboxylic bifunctionally-modified carbon nitride

2019 ◽  
Vol 55 (83) ◽  
pp. 12503-12506 ◽  
Author(s):  
Hao Tan ◽  
Peng Kong ◽  
Meixian Liu ◽  
Xianmo Gu ◽  
Zhanfeng Zheng
Keyword(s):  
Hydrogen Production ◽  
Active Sites ◽  
Carbon Nitride ◽  
Separation Efficiency ◽  
Promising Candidate ◽  
Methanol Reforming ◽  
Metal Free ◽  
Carrier Separation ◽  
Polymeric Carbon ◽  
Low Activity

Polymeric carbon nitride is a promising candidate for metal-free photocatalysis, but it is hampered by low activity due to poor carrier separation efficiency and lack of active sites.

Tailoring phenol photomineralization pathway over polymeric carbon nitride with cyano group multifunctional active sites

2021 ◽  
Vol 284 ◽  
pp. 119710
Author(s):  
Meixian Liu ◽  
Mengting Gao ◽  
Linjuan Pei ◽  
Yali Ji ◽  
Xianmo Gu ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Cyano Group ◽  
Polymeric Carbon

scholarly journals Water-Soluble Polymeric Carbon Nitride Colloidal Nanoparticles for Highly Selective Quasi-Homogeneous Photocatalysis

2019 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
Luís Mafra ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Narrow Size Distribution ◽  
New Paradigm ◽  
Redox Transformations ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

Heptazine-based polymeric carbon nitrides (PCN) are well established as promising photocatalysts for light-driven redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of active sites accessible for reactants. Herein, we report, for the first time, a bottom-up preparation of PCN nanoparticles with a narrow size distribution (~10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months, and allow carrying out photocatalysis under <i>quasi</i>-homogeneous conditions. The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to conventional solid PCN and was accompanied by simultaneous H<sub>2</sub>O<sub>2</sub> production <i>via</i> reduction of oxygen. The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity. This work thus establishes a new paradigm of easily operable <i>quasi-</i>homogeneous photocatalysis with PCN, and opens up a route for other applications in which liquid aqueous operation or processing of PCN is required.

Probing the effect of P-doping in polymeric carbon nitride on CO2 photocatalytic reduction

2020 ◽  
Vol 49 (44) ◽  
pp. 15750-15757
Author(s):  
Yangkun Guo ◽  
Min Wang ◽  
Jianjian Tian ◽  
Meng Shen ◽  
Lingxia Zhang ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Reduction Reaction ◽  
Photocatalytic Reduction ◽  
Polymeric Carbon

P-Doping promotes the generation and conversion of CO2− intermediate on polymeric carbon nitride photocatalysts during CO2 reduction reaction.

Bifunctional hydroxyl group over polymeric carbon nitride to achieve photocatalytic H2O2 production in ethanol aqueous solution with an apparent quantum yield of 52.8% at 420 nm

2019 ◽  
Vol 55 (88) ◽  
pp. 13279-13282 ◽  
Author(s):  
Weishu Hou ◽  
Yunxiang Li ◽  
Shuxin Ouyang ◽  
Huayu Chen ◽  
Jinhua Ye ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Yield ◽  
Carbon Nitride ◽  
Hydroxyl Group ◽  
H2o2 Production ◽  
Apparent Quantum Yield ◽  
Ethanol Aqueous Solution ◽  
Polymeric Carbon

Hydroxyl group modified polymeric carbon nitride achieves efficient photoreduction of O2 to H2O2 and highly selective photooxidization of C2H5OH simultaneously.

scholarly journals Water-Soluble Polymeric Carbon Nitride Colloidal Nanoparticles for Highly Selective Quasi-Homogeneous Photocatalysis

2019 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
Luís Mafra ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Narrow Size Distribution ◽  
New Paradigm ◽  
Redox Transformations ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

Heptazine-based polymeric carbon nitrides (PCN) are well established as promising photocatalysts for light-driven redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of active sites accessible for reactants. Herein, we report, for the first time, a bottom-up preparation of PCN nanoparticles with a narrow size distribution (~10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months, and allow carrying out photocatalysis under <i>quasi</i>-homogeneous conditions. The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to conventional solid PCN and was accompanied by simultaneous H<sub>2</sub>O<sub>2</sub> production <i>via</i> reduction of oxygen. The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity. This work thus establishes a new paradigm of easily operable <i>quasi-</i>homogeneous photocatalysis with PCN, and opens up a route for other applications in which liquid aqueous operation or processing of PCN is required.

Etching-induced highly porous polymeric carbon nitride with enhanced photocatalytic hydrogen evolution

2021 ◽  
Author(s):  
Xiang Wang ◽  
Yuguo Xia ◽  
Haimei Wang ◽  
Xiuling Jiao ◽  
Dairong Chen
Keyword(s):  
Specific Surface ◽  
Surface Charge ◽  
Surface Area ◽  
Charge Separation ◽  
Active Sites ◽  
Carbon Nitride ◽  
Separation Process ◽  
Large Specific Surface Area ◽  
Polymeric Carbon ◽  
Highly Porous

Photocatalytic catalysts with a large specific surface area generally can not only supply more active sites but also facilitate the surface charge separation process. Here, we present a facile strategy...

C-, N-Vacancy defect engineered polymeric carbon nitride towards photocatalysis: viewpoints and challenges

2021 ◽  
Vol 9 (1) ◽  
pp. 111-153
Author(s):  
Abhinandan Kumar ◽  
Pankaj Raizada ◽  
Ahmad Hosseini-Bandegharaei ◽  
Vijay Kumar Thakur ◽  
Van-Huy Nguyen ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Structural Features ◽  
Vacancy Defect ◽  
Semiconductor Material ◽  
Metal Free ◽  
Polymeric Semiconductor ◽  
Polymeric Carbon

As an alluring metal-free polymeric semiconductor material, graphite-like carbon nitride (g-C3N4; abbreviated as GCN) has triggered a new impetus in the field of photocatalysis, mainly favoured from its fascinating physicochemical and photoelectronic structural features.

Construction of brown mesoporous carbon nitride with a wide spectral response for high performance photocatalytic H2 evolution

2021 ◽  
Author(s):  
Jinzhou Chen ◽  
Xianglin Zhu ◽  
Zhifeng Jiang ◽  
Wei Zhang ◽  
Haiyan Ji ◽  
...  
Keyword(s):  
Active Sites ◽  
High Performance ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Spectral Response ◽  
2D Structure ◽  
Charge Separation Efficiency ◽  
The Rich ◽  
Mesoporous Carbon Nitride

Two-dimensional graphitic carbon nitride (2D CN) shows superior photocatalytic performance due to the high charge separation efficiency and the rich active sites endowed with the 2D structure. However, the 2D...

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