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

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.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yubao Zhao ◽  
Peng Zhang ◽  
Zhenchun Yang ◽  
Lina Li ◽  
Jingyu Gao ◽  
...  

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.


2022 ◽  
Author(s):  
Qingqing Gao ◽  
Qian Lei ◽  
Ruoyan Miao ◽  
Manyi Gao ◽  
Fang Song ◽  
...  

Polymeric carbon nitride (PCN) is an emerging metal-free photocatalysts with high stability but is plagued by low photocatalytic efficiency due to the rapid charge carrier recombination behavior. Herein, Bi doped...


2019 ◽  
Vol 256 ◽  
pp. 117794 ◽  
Author(s):  
Pengju Yang ◽  
Long Wang ◽  
Hangyu Zhuzhang ◽  
Ruirui Wang ◽  
Maria-Magdalena Titirici ◽  
...  

2019 ◽  
Vol 131 (11) ◽  
pp. 3471-3475 ◽  
Author(s):  
Guigang Zhang ◽  
Guosheng Li ◽  
Tobias Heil ◽  
Spiros Zafeiratos ◽  
Feili Lai ◽  
...  

2018 ◽  
Vol 54 (20) ◽  
pp. 2475-2478 ◽  
Author(s):  
Lijuan Shen ◽  
Ganchang Lei ◽  
Yuanxing Fang ◽  
Yanning Cao ◽  
Xinchen Wang ◽  
...  

Polymeric carbon nitride nanomesh has been prepared and demonstrated to be a novel and outstanding catalyst for H2S selective oxidation.


Author(s):  
Florent Yang ◽  
Vadym Kuznietsov ◽  
Michael Lublow ◽  
Christoph Merschjann ◽  
Alexander Steigert ◽  
...  

2021 ◽  
Author(s):  
Hongde Yu ◽  
Dong Wang

Covalent organic frameworks (COFs) with highly designable skeleton and inherent pores have emerged as promising organic photocatalysts for hydrogen production. However, inefficient solar light harvesting, strong excitonic effect, and the lack of active sites still pose major challenges to the rational design of COFs for efficient photocatalytic water splitting and the structure-property relationship has not been established. In this work, we investigated the fundamental mechanism of photoelectrochemical conversion in fully conjugated donor (D)-acceptor (A) COFs in Lieb lattice and proposed a facile strategy to achieve broad visible and near-infrared absorption, prompt exciton dissociation, tunable band alignment for overall water splitting, and metal-free catalysis of hydrogen production. Interestingly, we found that the exciton binding energy was substantially reduced with the narrowing of optical band gap and the increase of static dielectric constant. Further, we unraveled that the hydrogen bond played a vital role in suppressing the overpotential for hydrogen evolution reaction to enable metal-free catalysis. These findings not only highlight a novel route to modulating electronic properties of COFs towards high photocatalytic activity for water splitting, but also offer tremendous opportunities to design metal-free catalysts for other chemical transformations.


Author(s):  
Xiaojuan Bai ◽  
Tianqi Jia ◽  
Xuyu Wang ◽  
Shanshan Hou ◽  
Derek Hao ◽  
...  

As a green, visible-light-driven metal-free semiconductor material, graphitic carbon nitride (g-C3N4) has aroused tremendous significance in the fields of environmental purification and energy conversion. Inducing a polarization effect by creating...


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