Insight into the factors influencing the photocatalytic H2 evolution performance of molybdenum sulfide

2019 ◽  
Vol 43 (3) ◽  
pp. 1230-1237 ◽  
Author(s):  
Mingcai Yin ◽  
Wenli Zhang ◽  
Hui Li ◽  
Chaojun Wu ◽  
Fangfang Jia ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Performance ◽  
Molybdenum Sulfide ◽  
H2 Evolution ◽  
Key Factors ◽  
Factors Influencing ◽  
Insight Into ◽  
Photocatalytic H2 Evolution

The specific surface area and composition are found to be the key factors influencing the photocatalytic performance of MoS2+x.

scholarly journals Photocatalytic H2 Evolution, CO2 Reduction, and NOx Oxidation by Highly Exfoliated g-C3N4

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1147
Author(s):  
Nadia Todorova ◽  
Ilias Papailias ◽  
Tatiana Giannakopoulou ◽  
Nikolaos Ioannidis ◽  
Nikos Boukos ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Photocatalytic Performance ◽  
Uv Light ◽  
Co2 Reduction ◽  
H2 Production ◽  
Thermal Treatments ◽  
H2 Evolution ◽  
Photocatalytic H2 Evolution

g-C3N4, with specific surface area up to 513 m2/g, was prepared via three successive thermal treatments at 550 °C in air with gradual precursor mass decrease. The obtained bulk and exfoliated (1ex, 2ex and 3ex) g-C3N4 were characterized and tested as photocatalysts for H2 production, CO2 reduction and NOx oxidation. The exfoliated samples demonstrated graphene-like morphology with detached (2ex) and sponge-like framework (3ex) of layers. The surface area increased drastically from 20 m2/g (bulk) to 513 m2/g (3ex). The band gap (Eg) increased gradually from 2.70 to 3.04 eV. Superoxide radicals (·O2−) were mainly formed under UV and visible light. In comparison to the bulk, the exfoliated g-C3N4 demonstrated significant increase in H2 evolution (~6 times), CO2 reduction (~3 times) and NOx oxidation (~4 times) under UV light. Despite the Eg widening, the photocatalytic performance of the exfoliated g-C3N4 under visible light was improved too. The results were related to the large surface area and low e−-h+ recombination. The highly exfoliated g-C3N4 demonstrated selectivity towards H2 evolution reactions.

The Hydrothermal Synthesis and Photocatalysis of TiO2 Powders

2011 ◽  
Vol 183-185 ◽  
pp. 2024-2027
Author(s):  
Li Ming Jiang
Keyword(s):  
Photocatalytic Activity ◽  
Hydrothermal Synthesis ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Organic Molecule ◽  
Photocatalytic Performance ◽  
Hydrothermal Conditions ◽  
Anatase Structure

Titania powders were prepared under hydrothermal conditions by employing organic molecule β-cyclodextrin(CD) as template, and characterized by means of TGA、XRD、BET . The effects of the pH on the specific surface area and photocatalytic performance of titania were discussed. The results showed that titania powders were anatase structure;the titania powders with specific surface area up to 216.2 m2g-1 were prepared while the system pH was about 1 , and the powders had the best photocatalytic activity.

TiO2 composite films on different substrates with enhanced visible light photocatalytic performance

2020 ◽  
Vol 13 (07) ◽  
pp. 2051037
Author(s):  
Ke Han ◽  
Guobao Li ◽  
Fang Li ◽  
Mingming Yao
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Composite Films ◽  
Methyl Green ◽  
Photogenerated Electrons

For the sake of improving the photocatalytic performance of TiO2, we prepared the B/Ag/Fe tridoped TiO2 films on common glass and stone substrates by the sol–gel method. In this work, the optical absorption, recombination of photogenerated electrons (e−) and holes (h[Formula: see text]), crystal types, thermal stability, composition, specific surface area and photocatalytic activity of the modified TiO2 films were investigated. The results indicated that B/Ag/Fe tridoping not only enhanced the absorption of visible light by TiO2, but inhibited the recombination of electron–hole (e−/h[Formula: see text]) pairs. The tridoping also promoted the formation of anatase and prevented the transformation of anatase to rutile at high temperature. The composite TiO2 has a large specific surface area, about three times that of pure TiO2. The photocatalytic activity of the TiO2 films were evaluated by methyl green (MG) and formaldehyde degradation. In all samples, the B/Ag/Fe tridoped TiO2 film exhibited the highest degradation rate of MG under both ultraviolet and visible light irradiation. The improvement of photocatalytic performance of TiO2 films is due to the synergistic effect of the B/Ag/Fe tridoping, which enhances the absorption of visible light and prolongs the lifetime of e−/h[Formula: see text] pairs and facilitates transfer of interface charge.

scholarly journals Continuously Improved Photocatalytic Performance of Zn2SnO4/SnO2/Cu2O Composites by Structural Modulation and Band Alignment Modification

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1390 ◽  
Author(s):  
Tiekun Jia ◽  
Junchao An ◽  
Dongsheng Yu ◽  
Jili Li ◽  
Fang Fu ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Band Alignment ◽  
Energy Utilization ◽  
Structural Modulation ◽  
Hierarchical Architectures

Improving the photocatalytic performance of multi-component photocatalysts through structural modulation and band alignment engineering has attracted great interest in the context of solar energy utilization and conversion. In our work, Zn2SnO4/SnO2 hierarchical architectures comprising nanorod building block assemblies were first achieved via a facile solvothermal synthesis route with lysine and ethylenediamine (EDA) as directing agents, and then chemically etched in NaOH solution to enlarge the surface area and augment active sites. The etched Zn2SnO4/SnO2 hierarchical architectures were further decorated by Cu2O nanoparticles though an in situ chemical deposition method based on band alignment engineering. In comparison with unetched Zn2SnO4/SnO2, the specific surface area of Zn2SnO4/SnO2/Cu2O hierarchical architectures became larger, and the responsive region and absorbance intensity became wider and higher in the whole visible-light range. Zn2SnO4/SnO2/Cu2O hybrid photocatalysts presented enormously improved visible-light photocatalytic behaviour for Rhodamine B (RhB) decomposition. The enhancement of photocatalytic behaviour was dominantly attributed to the synergy effect of the larger specific surface area, higher light absorption capacity, and more effective photo-induced charge carrier separation and migration. A proposed mechanism for the enormously promoted photocatalytic behaviour is brought forth on the basis of the energy-band structure combined with experimental results.

scholarly journals The influence factors for gas adsorption with different ranks of coals

2017 ◽  
Vol 36 (3-4) ◽  
pp. 904-918 ◽  
Author(s):  
Deyong Guo ◽  
Xiaojie Guo
Keyword(s):  
Moisture Content ◽  
Specific Surface ◽  
Pore Structure ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Gas Adsorption ◽  
Total Pore Volume ◽  
Factors Influencing

In this paper, scanning electron microscopy, low-temperature N2 adsorption and CH4 isothermal adsorption experiments were performed on 11 coal samples with Ro,max between 0.98 and 3.07%. The pore structure characteristics of coals (specific surface area, total volume distribution) were studied to assess the gas adsorption capacity. The results indicate that there is significant heterogeneity on coal surface, containing numerous channel-like pores, bottle-shaped pores and wedge-shaped pores. Both Langmuir volume (VL) and Langmuir pressure (PL) show a stage change trend with the increase of coalification degree. For different coalification stages, there exist different factors influencing the VL and PL values. For low-rank coals (Ro,max < 1.1%), the increase of VL values and decrease of PL values are mainly due to the abundant primary pore and fracture within coal. For middle-rank coals (1.1% < Ro,max < 2.1%), the moisture content, vitrinite content and total pore volume are all the factors influencing VL, and the reduction of PL is mainly attributed to the decrease of moisture content and inertinite content. Meanwhile, this result is also closely related to the pore shape. For high-rank coals (Ro,max > 2.1%), VL values gradually increase and reach the maximum. When the coal has evolved into anthracite, liquid hydrocarbon within pore begins pyrolysis and gradually disappears, and a large number of macropores are converted into micropores, leading to the increase of specific surface area and total pore volume, corresponding to the increase of VL. In addition, the increase of vitrinite content within coal also contributes to the increase of VL. PL, reaches the minimum, indicating that the adsorption rate reaches the largest at the low pressure stage. The result is mainly controlled by the specific surface area and total pore volume of coal samples. This research results will provide a clearer insight into the relationship between adsorption parameters and coal rank, moisture content, maceral composition and pore structure, and it is of great significance for better assessing the gas adsorption capacity.

Role of Acetaldehyde on Synthesizing Large Surface Area Porous g-C3N4 Nanosheets with Enhanced Photocatalytic Performance by Using Acetaldehyde–Melamine

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050066
Author(s):  
Xiangxiang Cheng ◽  
Xiaojuan Xu ◽  
Hongliang Wang ◽  
He Cai ◽  
Lan Jia ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Low Cost ◽  
High Concentration ◽  
Air Atmosphere ◽  
Oxidative Etching

Large specific surface area porous g-C3N4 nanosheets were prepared by utilizing acetaldehyde-mediated melamine. The synthetic processes adopted two-step thermal treatments which are in N2 and then in an air atmosphere. The introduced acetaldehyde made melamine condensation incompletely and generated body defects in g-C3N4 when heated in N2. Further heating in air realized pores formation at sites of body defects, thus increase the specific surface area of g-C3N4. Notably, the introduction of acetaldehyde is beneficial to generate high concentration defects, which are active sites for thermal oxidative etching, and increase the yield of g-C3N4 by inhibiting the sublimation of melamine. The photocatalytic performance of obtained g-C3N4 was evaluated by the degradation of 2-propanol under visible light irradiation ([Formula: see text][Formula: see text]nm). The porous g-C3N4 exhibits excellent photocatalytic performance than bulk g-C3N4. The addition of trace acetaldehyde significantly increased the specific surface area and enhanced photocatalytic activity, providing a new idea for the development of simple, low-cost and high active g-C3N4 photocatalyst.

Regulation of band edge and specific surface area of BixInyOCl microsphere for excellent photocatalytic performance

2021 ◽  
Vol 867 ◽  
pp. 159052
Author(s):  
Yanguang Zhang ◽  
Jing Tian ◽  
Detong Tian ◽  
Weibing Li ◽  
Zhenze Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Photocatalytic Performance ◽  
Band Edge
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