Direct probing of atomically dispersed Ru species over multi-edged TiO2 for highly efficient photocatalytic hydrogen evolution

A cocatalyst is necessary for boosting the electron-hole separation efficiency and accelerating the reaction kinetics of semiconductors. As a result, it is of critical importance to in situ track the structural evolution of the cocatalyst during the photocatalytic process, but it remains very challenging. Here, atomically dispersed Ru atoms are decorated over multi-edged TiO2 spheres for photocatalytic hydrogen evolution. Experimental results not only demonstrate that the photogenerated electrons can be effectively transferred to the isolated Ru atoms for hydrogen evolution but also imply that the TiO2 architecture with multi-edges might facilitate the charge separation and transport. The change in valence and the evolution of electronic structure of Ru sites are well probed during the photocatalytic process. Specifically, the optimized catalyst produces the hydrogen evolution rate of 7.2 mmol g−1 hour−1, which is much higher than that of Pt-based cocatalyst systems and among the highest reported values.

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Enhanced effect of CdS on amorphous Mo15S19 for photocatalytic hydrogen evolution

New Journal of Chemistry ◽

10.1039/d0nj06221a ◽

2021 ◽

Author(s):

Yongkang Quan ◽

Guorong Wang ◽

Junke Li ◽

Zhiliang Jin

Keyword(s):

Hydrogen Evolution ◽

Recombination Rate ◽

Separation Efficiency ◽

Photocatalytic Hydrogen Evolution ◽

Photogenerated Electrons

Amorphous Mo15S19 loaded onto the surface of CdS improves the separation efficiency of photogenerated carriers, which reduces the recombination rate of photogenerated electrons and holes.

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Construction of Ag3PO4/SnO2 Heterojunction on Carbon Cloth with Enhanced Visible Light Photocatalytic Degradation

Applied Sciences ◽

10.3390/app10093238 ◽

2020 ◽

Vol 10 (9) ◽

pp. 3238

Author(s):

Min Liu ◽

Guangxin Wang ◽

Panpan Xu ◽

Yanfeng Zhu ◽

Wuhui Li

Keyword(s):

Visible Light ◽

Photocatalytic Performance ◽

Separation Efficiency ◽

Photogenerated Electron ◽

Carbon Cloth ◽

Electron Hole ◽

Step Process ◽

Photogenerated Electrons ◽

Rapid Transfer ◽

Visible Light Photocatalytic

In this study, the Ag3PO4/SnO2 heterojunction on carbon cloth (Ag3PO4/SnO2/CC) was successfully fabricated via a facile two-step process. The results showed that the Ag3PO4/SnO2/CC heterojunction exhibited a remarkable photocatalytic performance for the degradation of Rhodamine B (RhB) and methylene blue (MB), under visible light irradiation. The calculated k values for the degradation of RhB and MB over Ag3PO4/SnO2/CC are 0.04716 min−1 and 0.04916 min−1, which are higher than those calculated for the reactions over Ag3PO4/SnO2, Ag3PO4/CC and SnO2/CC, respectively. The enhanced photocatalytic activity could mainly be attributed to the improved separation efficiency of photogenerated electron-hole pairs, after the formation of the Ag3PO4/SnO2/CC heterojunction. Moreover, carbon cloth with a large specific surface area and excellent conductivity was used as the substrate, which helped to increase the contact area of dye solution with photocatalysts and the rapid transfer of photogenerated electrons. Notably, when compared with the powder catalyst, the catalysts supported on carbon cloth are easier to quickly recycle from the pollutant solution, thereby reducing the probability of recontamination.

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Photocatalytic hydrogen evolution on CdS–based composites derived from in situ carbonization of a sulfonic azo dye complex

Inorganic Chemistry Communications ◽

10.1016/j.inoche.2020.108370 ◽

2021 ◽

Vol 125 ◽

pp. 108370

Author(s):

Jun–Tao Wang ◽

Gui–Fang Liu ◽

Kai Yu ◽

Jian–Ying Xu ◽

Heng–Xin Liu ◽

...

Keyword(s):

Hydrogen Evolution ◽

Azo Dye ◽

Photocatalytic Hydrogen Evolution ◽

In Situ Carbonization

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In-Situ Synthesis of TiO2@GO Nanosheets for Polymers Degradation in a Natural Environment

Polymers ◽

10.3390/polym13132158 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2158

Author(s):

Yueqin Shi ◽

Zhanyang Yu ◽

Zhengjun Li ◽

Xiaodong Zhao ◽

Yongjun Yuan

Keyword(s):

Natural Environment ◽

New Technologies ◽

Separation Efficiency ◽

Basic Mechanism ◽

Chemical Degradation ◽

Natural Environments ◽

Additional Energy ◽

Photogenerated Electrons ◽

Main Components

Plastic photodegradation naturally takes 300–500 years, and their chemical degradation typically needs additional energy or causes secondary pollution. The main components of global plastic are polymers. Hence, new technologies are urgently required for the effective decomposition of the polymers in natural environments, which lays the foundation for this study on future plastic degradation. This study synthesizes the in-situ growth of TiO2 at graphene oxide (GO) matrix to form the TiO2@GO photocatalyst, and studies its application in conjugated polymers’ photodegradation. The photodegradation process could be probed by UV-vis absorption originating from the conjugated backbone of polymers. We have found that the complete decomposition of various polymers in a natural environment by employing the photocatalyst TiO2@GO within 12 days. It is obvious that the TiO2@GO shows a higher photocatalyst activity than the TiO2, due to the higher crystallinity morphology and smaller size of TiO2, and the faster transmission of photogenerated electrons from TiO2 to GO. The stronger fluorescence (FL) intensity of TiO2@GO compared to TiO2 at the terephthalic acid aqueous solution indicates that more hydroxyl radicals (•OH) are produced for TiO2@GO. This further confirms that the GO could effectively decrease the generation of recombination centers, enhance the separation efficiency of photoinduced electrons and holes, and increase the photocatalytic activity of TiO2@GO. This work establishes the underlying basic mechanism of polymers photodegradation, which might open new avenues for simultaneously addressing the white pollution crisis in a natural environment.

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Band Engineering and Morphology Control of Oxygen-Incorporated Graphitic Carbon Nitride Porous Nanosheets for Highly Efficient Photocatalytic Hydrogen Evolution

Nano-Micro Letters ◽

10.1007/s40820-020-00571-6 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Yunyan Wu ◽

Pan Xiong ◽

Jianchun Wu ◽

Zengliang Huang ◽

Jingwen Sun ◽

...

Keyword(s):

Surface Area ◽

Hydrogen Evolution ◽

Carbon Nitride ◽

Separation Efficiency ◽

Physical Adsorption ◽

Graphitic Carbon ◽

Graphitic Carbon Nitride ◽

Photocatalytic Hydrogen Evolution ◽

Band Engineering ◽

Highly Efficient

AbstractGraphitic carbon nitride (g-C3N4)-based photocatalysts have shown great potential in the splitting of water. However, the intrinsic drawbacks of g-C3N4, such as low surface area, poor diffusion, and charge separation efficiency, remain as the bottleneck to achieve highly efficient hydrogen evolution. Here, a hollow oxygen-incorporated g-C3N4 nanosheet (OCN) with an improved surface area of 148.5 m2 g−1 is fabricated by the multiple thermal treatments under the N2/O2 atmosphere, wherein the C–O bonds are formed through two ways of physical adsorption and doping. The physical characterization and theoretical calculation indicate that the O-adsorption can promote the generation of defects, leading to the formation of hollow morphology, while the O-doping results in reduced band gap of g-C3N4. The optimized OCN shows an excellent photocatalytic hydrogen evolution activity of 3519.6 μmol g−1 h−1 for ~ 20 h, which is over four times higher than that of g-C3N4 (850.1 μmol g−1 h−1) and outperforms most of the reported g-C3N4 catalysts.

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