scholarly journals Synthesis of n-Alkoxy Derivatives of Layered Perovskite-Like Niobate HCa2Nb3O10 and Study of Their Photocatalytic Activity for Hydrogen Production from an Aqueous Solution of Methanol

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 897
Author(s):  
Vladimir V. Voytovich ◽  
Sergey A. Kurnosenko ◽  
Oleg I. Silyukov ◽  
Ivan A. Rodionov ◽  
Alexander N. Bugrov ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Hydrogen Generation ◽  
Pt Nanoparticles ◽  
Layered Compounds ◽  
Layered Perovskite ◽  
Primary Alcohols ◽  
Absorption Region ◽  
Photocatalytic Hydrogen Generation ◽  
Alkoxy Groups

A series of hybrid inorganic–organic niobates HCa2Nb3O10×ROH, containing n-alkoxy groups of primary alcohols (R = Me, Et, Pr, Bu, Hx, and Dc) grafted in the interlayer space, has been studied for the first time in relation to photocatalytic hydrogen generation from a model 1 mol % aqueous solution of methanol under ultraviolet irradiation. Photocatalytic activity was measured both for bare samples and for their composites with Pt nanoparticles as a cocatalyst. The advanced measurement scheme allowed monitoring the volume concentration of a sample in a suspension during the experiment, its pH, and possible exfoliation of layered compounds into nanolayers. In the series of n-alkoxy derivatives, the maximum rate of hydrogen evolution was achieved over a Pt-loaded ethoxy derivative HCa2Nb3O10×EtOH/Pt. Its apparent quantum efficiency of 20.6% in the 220–350 nm range was found not to be caused by changes in the light absorption region or specific surface area upon ethanol grafting. Moreover, the amounts of hydrogen released during the measurements significantly exceeded those of interlayer organic components, indicating that hydrogen is generated from the reaction solution rather than from the hybrid material.

scholarly journals Photocatalytic Activity of n-Alkylamine and n-Alkoxy Derivatives of Layered Perovskite-like Titanates H2Ln2Ti3O10 (Ln = La, Nd) in the Reaction of Hydrogen Production From an Aqueous Solution of Methanol

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1279
Author(s):  
Sergei Kurnosenko ◽  
Vladimir Voytovich ◽  
Oleg Silyukov ◽  
Ivan Rodionov ◽  
Sergei Kirichenko ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Interlayer Space ◽  
Pt Nanoparticles ◽  
Layered Compounds ◽  
Layered Perovskite ◽  
Organic Components ◽  
Apparent Quantum Efficiency ◽  
Alkoxy Groups

Two series of hybrid inorganic-organic derivatives, obtained via the modification of protonated Ruddlesden–Popper phases H2Ln2Ti3O10 (Ln = La, Nd) with intercalated n-alkylamines and grafted n-alkoxy groups, have been systematically investigated in relation to photocatalytic hydrogen production from a model of 1 mol % aqueous solution of methanol for the first time. Photocatalytic measurements were performed both for bare samples and for their composites with Pt nanoparticles as a cocatalyst using an advanced scheme, including dark stages, monitoring of the volume concentration of the sample in the reaction suspension during the experiment, shifts of its pH and possible exfoliation of layered compounds into nanolayers. It was found that the incorporation of organic components into the interlayer space of the titanates increases their photocatalytic activity up to 117 times compared with that of the initial compounds. Additional platinization of the hybrid samples’ surface allowed for achieving apparent quantum efficiency of hydrogen evolution of more than 40%. It was established that the photocatalytic activity of the hybrid samples correlates with the hydration degree of their interlayer space, which is considered a separate reaction zone in photocatalysis, and that hydrogen indeed generates from the aqueous methanol solution rather than from organic components of the derivatives.

scholarly journals Enhanced Photocatalytic Hydrogen Generation by Optimized Plasmonic Hot Electron Injection in Structure-Adjustable Au-ZnO Hybrids

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 376
Author(s):  
Youlong Chen ◽  
Liang Ma ◽  
Sijing Ding
Keyword(s):  
Photocatalytic Activity ◽  
Transient Absorption ◽  
Hydrogen Generation ◽  
Electron Injection ◽  
Resonance Excitation ◽  
Core Shell ◽  
Hot Electron ◽  
Photocatalytic Hydrogen Generation ◽  
Hot Electron Injection ◽  
Apparent Quantum Efficiency

Plasmonic Au-ZnO hybrids with adjustable structures (including Au-decorated ZnO and core–shell Au@ZnO with dense and porous ZnO shells) and the optimized hot electron-driven photocatalytic activity were successfully prepared. It was found that the Au@ZnO core–shell hybrids with porous morphology had the highest plasmon-enhanced photocatalytic hydrogen generation activity under visible light irradiation. The wavelength-dependent photocatalytic tests verified that Au@ZnO with porous ZnO shells had the highest apparent quantum efficiency upon resonance excitation. The ultrafast transient absorption measurements revealed that Au@ZnO with porous ZnO shells had the fastest plasmon-induced hot electron injection, which was thought to be the reason for the improved photocatalytic activity. This work might provide a promising route to designing photocatalytic and photoelectric materials.

scholarly journals Preparation, characterization and photocatalytic activity of Co3O4/LiNbO3 composite

2013 ◽  
Vol 11 (6) ◽  
pp. 920-926 ◽  
Author(s):  
Beata Zielinska ◽  
Magdalena Janus ◽  
Ryszard Kalenczuk
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Generation ◽  
Cobalt Content ◽  
Cobalt Nitrate ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Photocatalytic Hydrogen Generation ◽  
Content Range

AbstractThe Co3O4/LiNbO3 composites were synthesized by impregnation of LiNbO3 in an aqueous solution of cobalt nitrate and next by calcination at 400°C. The activity of produced samples has been investigated in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were studied using X-ray diffraction (XRD), diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic techniques, respectively. The influence of cobalt content (range from 0.5 wt.% to 4 wt.%) on the photocatalytic activity of Co3O4/LiNbO3 composites for photocatalytic hydrogen generation has been investigated. Co3O4/LiNbO3 composites exhibited higher than LiNbO3 photocatalytic activity for hydrogen generation. The highest H2 evolution efficiency was observed for Co3O4/LiNbO3 composite with 3 wt.% cobalt content. The amount of H2 obtained in the presence of LiNbO3 and Co3O4/LiNbO3 (3 wt.% of cobalt content) was 1.38 µmol/min and 2.59 µmol min−1, respectively.

Noble-metal loading reverses temperature dependent photocatalytic hydrogen generation in methanol–water solutions

2016 ◽  
Vol 52 (78) ◽  
pp. 11657-11660 ◽  
Author(s):  
Liqun Ye ◽  
Ka Him Chu ◽  
Bo Wang ◽  
Dan Wu ◽  
Haiquan Xie ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Noble Metal ◽  
Hydrogen Generation ◽  
Temperature Dependent ◽  
Water Solutions ◽  
Metal Loading ◽  
Photocatalytic Hydrogen Generation ◽  
Methanol Solutions ◽  
Activity Trends

Noble-metal (Pt or Au) loading reverses the temperature dependent photocatalytic activity trends of photocatalytic hydrogen generation in water–methanol solutions.

A dye-like ligand-based metal–organic framework for efficient photocatalytic hydrogen production from aqueous solution

2016 ◽  
Vol 6 (11) ◽  
pp. 3840-3844 ◽  
Author(s):  
Xiaojun Sun ◽  
Qi Yu ◽  
Fengming Zhang ◽  
Jinzhi Wei ◽  
Ping Yang
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Hydrogen Generation ◽  
Metal Organic Framework ◽  
Co Catalyst ◽  
Photocatalytic Hydrogen Production ◽  
Metal Organic ◽  
Organic Framework

A dye-like based Gd-MOF exhibits efficient photocatalytic activity for hydrogen generation without a co-catalyst. Depositing Ag further enhances its activity.

ZnS/CuS nanotubes for visible light-driven photocatalytic hydrogen generation

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 84493-84499 ◽  
Author(s):  
Yi-Biao Shao ◽  
Long-Hao Wang ◽  
Jian-Hua Huang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Hydrogen Generation ◽  
Visible Light Photocatalytic Activity ◽  
Photocatalytic Hydrogen Generation ◽  
Visible Light Driven ◽  
Visible Light Photocatalytic

ZnS/CuS nanotubes exhibit visible-light photocatalytic activity for H2 evolution without cocatalysts, resulting from the heterojunctions between ZnS and CuS nanoparticles.

scholarly journals Charge-transfer regulated visible light driven photocatalytic H2 production and CO2 reduction in tetrathiafulvalene based coordination polymer gel

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Parul Verma ◽  
Ashish Singh ◽  
Faruk Ahamed Rahimi ◽  
Pallavi Sarkar ◽  
Sukhendu Nath ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Coordination Polymer ◽  
Visible Light ◽  
Self Assembly ◽  
Hydrogen Generation ◽  
Co2 Reduction ◽  
Pt Nanoparticles ◽  
Polymer Gel

AbstractThe much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to fuels via hydrogen generation from water or CO2 reduction. Herein, a soft processable metal-organic hybrid material is developed and studied for photocatalytic activity towards H2 production and CO2 reduction to CO and CH4 under visible light as well as direct sunlight irradiation. A tetrapodal low molecular weight gelator (LMWG) is synthesized by integrating tetrathiafulvalene (TTF) and terpyridine (TPY) derivatives through amide linkages and results in TPY-TTF LMWG. The TPY-TTF LMWG acts as a linker, and self-assembly of this gelator molecules with ZnII ions results in a coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF CPG shows high photocatalytic activity towards H2 production (530 μmol g−1h−1) and CO2 reduction to CO (438 μmol g−1h−1, selectivity > 99%) regulated by charge-transfer interactions. Furthermore, in situ stabilization of Pt nanoparticles on CPG (Pt@Zn-TPY-TTF) enhances H2 evolution (14727 μmol g−1h−1). Importantly, Pt@Zn-TPY-TTF CPG produces CH4 (292 μmol g−1h−1, selectivity > 97%) as CO2 reduction product instead of CO. The real-time CO2 reduction reaction is monitored by in situ DRIFT study, and the plausible mechanism is derived computationally.

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