scholarly journals Preparation of NiS/ZnIn2S4 as a superior photocatalyst for hydrogen evolution under visible light irradiation

2013 ◽  
Vol 4 ◽  
pp. 949-955 ◽  
Author(s):  
Liang Wei ◽  
Yongjuan Chen ◽  
Jialin Zhao ◽  
Zhaohui Li

In this study, NiS/ZnIn2S4 nanocomposites were successfully prepared via a facile two-step hydrothermal process. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Their photocatalytic performance for hydrogen evolution under visible light irradiation was also investigated. It was found that the photocatalytic hydrogen evolution activity over hexagonal ZnIn2S4 can be significantly increased by loading NiS as a co-catalyst. The formation of a good junction between ZnIn2S4 and NiS via the two step hydrothermal processes is beneficial for the directional migration of the photo-excited electrons from ZnIn2S4 to NiS. The highest photocatalytic hydrogen evolution rate (104.7 μmol/h), which is even higher than that over Pt/ZnIn2S4 nanocomposite (77.8 μmol/h), was observed over an optimum NiS loading amount of 0.5 wt %. This work demonstrates a high potential of the developing of environmental friendly, cheap noble-metal-free co-catalyst for semiconductor-based photocatalytic hydrogen evolution.

2021 ◽  
Vol 1035 ◽  
pp. 1043-1049
Author(s):  
Di Xiang ◽  
Chang Long Shao

A simple route has been developed for the synthesis of Ag2O/ZnO heterostructures and the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) spectroscopy analysis. Considering the porous structure of Ag2O/ZnO, the photocatalytic degradation for the organic dyes, such as eosin red (ER), methyl orange (MO), methylene blue (MB) and rhodamine B (RhB), under visible light irradiation was investigated in detail. Noticeably, Ag2O/ZnO just took 40 min to degrade 96 % MB. The rate of degradation using the Ag2O/ZnO heterostructures was 2.3 times faster than that of the bare porous ZnO nanospheres under visible light irradiation due to that the recombination of the photogenerated charge was inhibited greatly in the p-type Ag2O and n-type ZnO semiconductor. So the Ag2O/ZnO heterostuctures showed the potential application on environmental remediation.


RSC Advances ◽  
2020 ◽  
Vol 10 (21) ◽  
pp. 12519-12534 ◽  
Author(s):  
Claudio Imparato ◽  
Giuseppina Iervolino ◽  
Marzia Fantauzzi ◽  
Can Koral ◽  
Wojciech Macyk ◽  
...  

Defective TiO2/C bulk heterostructures exhibit visible light photoresponsivity and remarkable H2 evolution rates under both UV and visible light irradiation.


2017 ◽  
Vol 46 (40) ◽  
pp. 13793-13801 ◽  
Author(s):  
Tengfei Wu ◽  
Peifang Wang ◽  
Jin Qian ◽  
Yanhui Ao ◽  
Chao Wang ◽  
...  

A highly efficient noble metal free Ni2P–CdS/g-C3N4 composite was constructed based on the concept of combining heterojunction engineering with co-catalyst modification.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Qingyun Chen ◽  
Cheng Suo ◽  
Shu Zhang ◽  
Yunhai Wang

To investigate the effect of PdS as a cocatalyst for photocatalytic hydrogen evolution, nanostructured PdS/CdS were prepared by an in situ coprecipitation and hydrothermal method, respectively. The as-prepared photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible absorption spectra, and photoluminescence spectra (PL). With PdS highly dispersed in the CdS nanostructures, the photoactivity was evaluated by hydrogen evolution from aqueous solution containing Na2S/Na2SO3as sacrificial reagents under visible light irradiation. When the concentration of PdS was 1% by weight, PdS/CdS, prepared by the in situ coprecipitation, showed the highest photocatalytic activity, while that prepared by hydrothermal method showed the most stability for hydrogen evolution. The effect of highly dispersed PdS on the photoactivity was discussed.


Author(s):  
Yaping Guo ◽  
Jianyang Sun ◽  
Hui Chang ◽  
Xu Zhao

A simple, effective and environmental-friendly method was adopted for enhancing the photocatalytic activity of g-C3N4 in the reduction of aqueous Cr(Ⅵ) under visible-light irradiation. The enhancement was achieved via treatment of g-C3N4 in organic solvent with addition of NaOH particles by ultrasonic process for two hours. The results demonstrated that the treated g-C3N4 exhibited much higher photocatalytic activity than pristine g-C3N4 in the reduction of Cr(VI) . Under visible light irradiation for 120 min, the reduced ratios of Cr(VI) with the initial concentration of 50 mg/L in the presence of the treated g-C3N4and pristine g-C3N4 were 100% and 37.1%, respectively. With the addition of fulvic acid, Cr(VI) was efficiently removed at 40 min. Based on the characterization results of the structures and other physiochemical properties of the treated g-C3N4 and pristine g-C3N4 by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV Vis diffuse reflectance, the possible reasons responsible for the enhanced photocatalytic activity of the treated g-C3N4 were proposed. The yield and mechanism of different exfoliation methods were compared by semi-quantitative method.


2018 ◽  
Vol 8 (5) ◽  
pp. 1375-1382 ◽  
Author(s):  
Junying Liu ◽  
Wenjian Fang ◽  
Zhidong Wei ◽  
Zhen Qin ◽  
Zhi Jiang ◽  
...  

Metallic 1T-LixMoS2 is an effective co-catalyst for photocatalytic hydrogen evolution over ZnIn2S4 because of its high electrical conductivity and high densities of active sites.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


2020 ◽  
Vol 10 (6) ◽  
pp. 1609-1618 ◽  
Author(s):  
Chao Zhang ◽  
Jiandong Liu ◽  
Xingliang Liu ◽  
Shiai Xu

Reaction mechanism for the higher photocatalytic performance of H2 production of g-C3N4NSs/TC1 under visible light irradiation (λ ≥ 400 nm).


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