scholarly journals Effects of RhCrOx Cocatalyst Loaded on Different Metal Doped LaFeO3 Perovskites with Photocatalytic Hydrogen Performance under Visible Light Irradiation

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 612
Author(s):  
Tzu Hsuan Chiang ◽  
Gujjula Viswanath ◽  
Yu-Si Chen
Keyword(s):  
Electron Microscope ◽  
Water Splitting ◽  
Fossil Fuels ◽  
H2 Production ◽  
Photoelectron Spectra ◽  
Evolution Rate ◽  
Impregnation Method ◽  
H2 Evolution ◽  
X Ray ◽  
Photocatalytic H2 Evolution

Photocatalytic hydrogen (H2) production by water splitting provides an alternative to fossil fuels using clean and renewable energy, which gives important requirements about the efficiency of photocatalysts, co-catalysts, and sacrificial agents. To achieve higher H2 production efficiencies from water splitting, the study uses different metals such as yttrium (Y), praseodymium (Pr), magnesium (Mg), Indium (In), calcium (Ca), europium (Eu), and terbium (Tb) doped lanthanum iron oxide (LaFeO3) perovskites. They were synthesized using a co-precipitate method in a citric acid solution, which was loaded with the rhodium chromium oxide (RhCrOx) cocatalysts by an impregnation method along with a detailed investigation of photocatalytic hydrogen evolution performance. Photoluminescence (PL) and UV–Vis diffuse reflectance spectra (DRS) measured the rate of electron–hole recombination for RhCrOx/Pr-LaFeO3 photocatalysts, and X-ray powder diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), and X-ray photoelectron spectra (XPS) analyzed their characteristics. The experimental results obtained show that the samples with 0.5 wt.% RhCrOx loading and 0.1 M Pr-doped LaFeO3 calcined at a temperature of 700 °C (0.1Pr-LaFeO3-700) exhibited the highest photocatalytic H2 evolution rate of 127 µmol h−1 g−1, which is 34% higher photocatalytic H2 evolution performance than undoped LaFeO3 photocatalysts (94.8 μmol h−1 g−1). A measure of 20% of triethanolamine (TEOA) enabled a high hole capture capability and promoted 0.1-Pr-LaFeO3-700 to get the highest H2 evolution rate.

scholarly journals Pt Deposites on TiO2 for Photocatalytic H2 Evolution: Pt Is Not Only the Cocatalyst, but Also the Defect Repair Agent

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1047 ◽  
Author(s):  
Zhan Shu ◽  
Yandi Cai ◽  
Jiawei Ji ◽  
Changjin Tang ◽  
Shuohan Yu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Charge Separation ◽  
H2 Production ◽  
H2 Evolution ◽  
X Ray ◽  
Production Activity ◽  
Defect Repair ◽  
New Perspective ◽  
Photocatalytic H2 Evolution

Pt, as a common cocatalyst, has been widely used in photocatalytic H2 evolution. However, the specific role of Pt in photocatalytic H2 evolution has not been thoroughly studied. In this paper, by employing three Pt sources with different charges (positive, negative and neutral), we systematically studied the charge effect of Pt sources on photocatalytic H2 evolution via TiO2 catalyst. According to the results of Raman, X-ray photoelectron spectroscopy (XPS), recycle experiments and photocurrent characterizations, it was found that TiO2 would produce electropositive defects during photocatalytic H2 evolution, inevitably leading to the decline of H2 production activity. Thanks to the electrostatic interaction, the electronegative Pt source not only promoted charge separation, but preferential deposited on electropositive defects, which acted as the defect repair agent, and thus resulted in the increased photocatalytic stability. This work may provide a new perspective for enhancing photocatalytic stability of hydrogen production.

scholarly journals g-C3N4 Sensitized by an Indoline Dye for Photocatalytic H2 Evolution

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1055
Author(s):  
Yihang Chen ◽  
Yanfei Liu ◽  
Zhen Ma
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Water Splitting ◽  
H2 Production ◽  
Charge Carriers ◽  
H2 Evolution ◽  
Co Catalyst ◽  
Efficient Separation ◽  
Photocatalytic H2 Evolution ◽  
Hcl Solution

Protonated g-C3N4 (pCN) formed by treating bulk g-C3N4 with an aqueous HCl solution was modified with D149 dye, i.e., 5-[[4[4-(2,2-diphenylethenyl) phenyl]-1,2,3,3a,4,8b-hexahydrocyclopent[b]indol-7-yl] methylene]-2-(3-ethyl-4-oxo-2-thioxo-5-thiazolidinylidene)-4-oxo-thiazolidin-2-ylidenerhodanine, for photocatalytic water splitting (using Pt as a co-catalyst). The D149/pCN-Pt composite showed a much higher rate (2138.2 µmol·h−1·g−1) of H2 production than pCN-Pt (657.0 µmol·h−1·g−1). Through relevant characterization, the significantly high activity of D149/pCN-Pt was linked to improved absorption of visible light, accelerated electron transfer, and more efficient separation of charge carriers. The presence of both D149 and Pt was found to be important for these factors. A mechanism was proposed.

scholarly journals Hydrothermal Synthesis of rGO/PbTiO3 Photocatalyst and Its Photocatalytic H2 Evolution Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Chunyan Wang ◽  
Lianwei Shan ◽  
Dongyuan Song ◽  
Yanwei Xiao ◽  
Jagadeesh Suriyaprakash
Keyword(s):  
Photocatalytic Performance ◽  
H2 Evolution ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Efficient Charge ◽  
One Step ◽  
Photocatalytic H2 Evolution

In this letter, we investigated the photocatalytic activity of the newly formed rGO/PbTiO3 composites, which are synthesized by a one-step hydrothermal route. By adjusting the amount of reduced graphene oxide (rGO) (0, 0.15, 0.30, 0.60, and 1.20 wt%) with the PbTiO3, we constructed various photocatalysts for this investigation. The crystal structure and morphology of the various composites were studied by powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Photoelectron spectroscopic study revealed that the band structure of the newly formed composites and efficient charge separation can be obtained by the interfaces of various rGO content. In addition, the photocatalytic performance of the synthesized composites was explored by H2 evolution and rhodamine blue (RhB) degradation. The obtained results indicated that the addition of the appropriate amount of rGO could improve the activity of pure PbTiO3, significantly.

Solvothermal route to Bi3Se4 nanorods at low temperature

2001 ◽  
Vol 16 (12) ◽  
pp. 3361-3365 ◽  
Author(s):  
Yuan-fang Liu ◽  
Jing-hui Zeng ◽  
Wei-xin Zhang ◽  
Wei-chao Yu ◽  
Yi-tai Qian ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Reaction Mechanism ◽  
Low Temperature ◽  
Hydrazine Hydrate ◽  
Photoelectron Spectra ◽  
Elemental Selenium ◽  
X Ray ◽  
Transmission Electron ◽  
Microscope Images ◽  
Diffraction Patterns

Nanorods Bi3Se4 were synthesized directly through the reaction between BiCl3 and elemental selenium in an autoclave with hydrazine hydrate as solvent at 165 °C for 10 h. X-ray powder diffraction patterns, x-ray photoelectron spectra, and transmission electron microscope images show that the products are well-crystallized hexagonal Bi3Se4 nanorods. The solvent hydrazine hydrate played an important role in formation and growth of Bi3Se4 nanorods. The possible reaction mechanism was proposed.

Preparation and Characterization of Cu Loaded TiO2 Nanotube Arrays and their Photocatalytic Activity

2011 ◽  
Vol 364 ◽  
pp. 377-381 ◽  
Author(s):  
Syazwani Mohd Zaki ◽  
Srimala Sreekantan
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Anatase Phase ◽  
Average Diameter ◽  
Photoelectron Spectra ◽  
Nanotube Arrays ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
X Ray

This paper described the preparation of Cu loaded TiO₂ nanotube arrays. Firstly, TiO₂ nanotube arrays were formed by anodization. Afterwards, the formed nanotube arrays were incorporated with Cu by wet impregnation method. The soaking time and concentration were varied to obtain an optimum set of parameter for Cu incorporation in TiO₂ nanotubes. After anodization, all samples were annealed at 400°C for 4 hours to obtain anatase phase. The nanotube arrays were characterized by field emission scanning electron microscopy (FESEM), x-ray diffraction (XRD) and x-ray photoelectron spectra (XPS). An average diameter 63.02 nm and length 12.15µm were obtained for TiO₂ nanotubes. The photocatalytic activity of these nanotubes were investigated with methyl orange (MO) and the TiO₂ nanotube prepared in 0.01M of Cu (NO₃)₂ solution within 3 hours demonstrates the highest photocatalytic activity with 83.6% degradation of methyl orange. Keywords: copper doping, wet impregnation, photocatalytic activity

scholarly journals Preparation and Characterization of Cu-doped TiO2 nanomaterials with Anatase/rutile/brookite Triphasic Structure and their Photocatalytic Activity

2021 ◽  
Author(s):  
Xiaodong Zhu ◽  
Qin Zhou ◽  
Yangwen Xia ◽  
Juan Wang ◽  
Hongjin Chen ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Electron Microscope ◽  
Hydrothermal Process ◽  
Degradation Process ◽  
High Photocatalytic Activity ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Surface Areas ◽  
Photogenerated Electrons ◽  
Degradation Degree

Abstract Pure TiO2 and different concentrations of Cu–doped TiO2 with anatase/rutile/brookite triphasic structure were successfully synthesized through a simple hydrothermal process and characterized by X–ray diffraction (XRD), Raman, scanning electron microscope (SEM), transmission electron microscope (TEM), X–ray photoelectron spectra (XPS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL) and Brunauer-Emmett-Teller surface area (BET). Both pure and Cu–doped TiO2 show relatively high photocatalytic activity owing to their considerable surface areas. Moreover, the three–phase coexisting structure and the conversion between Cu2+ and Cu+ ions facilitate the separation of photogenerated electrons and holes, which is favorable for photocatalytic performance. 1%Cu–TiO2 exhibits the highest photocatalytic activity and the degradation degree of rhodamine B (RhB) reaches 93.5% after 30 min, which is higher than that of monophasic/biphasic 1%Cu–TiO2. ·O2− radical is the main active specie, and h+ and ·OH are subsidiary in the degradation process.

scholarly journals Histidine Decorated Nanoparticles of CdS for Highly Efficient H2 Production via Water Splitting

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3738
Author(s):  
Fumiya Tojo ◽  
Manabu Ishizaki ◽  
Shigeru Kubota ◽  
Masato Kurihara ◽  
Fumihiko Hirose ◽  
...  
Keyword(s):  
Cadmium Sulfide ◽  
Water Splitting ◽  
Solvothermal Method ◽  
H2 Production ◽  
Sem Analysis ◽  
Cds Nanoparticles ◽  
H2 Evolution ◽  
X Ray Diffraction ◽  
Hexagonal Wurtzite Crystal Structure ◽  
Xrd Patterns

Pure cadmium sulfide and histidine decorated cadmium sulfide nanocomposites are prepared by the hydrothermal or solvothermal method. Scanning electron microscopy (SEM) analysis shows that the particle sizes of pure cadmium sulfide (pu/CdS) and histidine decorated cadmium sulfide prepared by the hydrothermal method (hi/CdS) range from 0.75 to 3.0 μm. However, when a solvothermal method is used, the particle size of histidine decorated cadmium sulfide (so/CdS) ranges from 50 to 300 nm. X-ray diffraction (XRD) patterns show that all samples (pu/CdS, hi/CdS and so/CdS) have a hexagonal wurtzite crystal structure but so/CdS has a poor crystallinity compared to the others. The as-prepared samples are applied to photocatalytic hydrogen production via water splitting and the results show that the highest H2 evolution rate for pu/CdS and hi/CdS are 1250 and 1950 μmol·g−1·h−1, respectively. On the other hand, the so/CdS sample has a rate of 6020 μmol·g−1·h−1, which is about five times higher than that of the pu/CdS sample. The increased specific surface area of so/CdS nanoparticles and effective charge separation by histidine molecules are attributed to the improved H2 evolution.

Self-assembly and photocatalytic H2 evolution activity of two unprecedented polytantalotungstates based on the largest {Ta18} and {Ta18Yb2} clusters

2016 ◽  
Vol 52 (95) ◽  
pp. 13787-13790 ◽  
Author(s):  
Peng Huang ◽  
Chao Qin ◽  
Yu Zhou ◽  
Yu-Mei Hong ◽  
Xin-Long Wang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Self Assembly ◽  
H2 Evolution ◽  
Photocatalytic Water Splitting ◽  
Photocatalytic H2 Evolution

Two unprecedented polytantalotungstates, 1 and 2 based on the largest {Ta18} and {Ta18Yb2} clusters, respectively, were synthesized. 1 and 2 exhibit significant UV photocatalytic water splitting activity.

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