scholarly journals MgCr-LDH Nanoplatelets as Effective Oxidation Catalysts for Visible Light-Triggered Rhodamine B Degradation

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1072
Author(s):  
Susanginee Nayak ◽  
Kulamani Parida
Keyword(s):  
Rhodamine B ◽  
Charge Separation ◽  
Active Sites ◽  
Catalytic Efficiency ◽  
Charge Trapping ◽  
Photocurrent Density ◽  
Active Species ◽  
Physico Chemical ◽  
Surface Active ◽  
Hexagonal Platelet

In this work, we successfully exfoliated MgCr-(NO3−) LDH with large purity by a simple formamide method followed by post-hydrothermal treatment and characterized by different physico-chemical techniques. The UV-DRS study persuades the red-shifted absorption band and suitable band gap of MgCr-(NO3−) LDH for optimum light harvestation ability related to the optical properties. Alternatively, the production of elevated photocurrent density of MgCr-(NO3−) LDH (3:1, 80 °C) in the anodic direction was verified by the LSV study, which further revealed their effective charge separation efficacy. These MgCr-LDH nanosheets (3:1, 80 °C) displayed the superior Rhodamine B (RhB) degradation efficiency of 95.0% at 0.80 kW/m2 solar light intensity in 2 h. The tremendous catalytic performances of MgCr-LDH (3:1, 80 °C) were typically linked with the formation of surface-active sites for the charge trapping process due to the presence of uncoordinated metallocenters during the exfoliation process. Furthermore, the maximum amount of the active free atoms at the edges of the hexagonal platelet of MgCr-LDH causes severance of the nanosheets, which generates house of platelets of particle size ~20–50 nm for light harvestation, promoting easy charge separation and catalytic efficiency. In addition, radical quenching tests revealed that h+ and •OH play as major active species responsible for the RhB degradation.

scholarly journals ACTIVATED ADSORBENT PREPARED FROM BOVINE BONE WASTE: PHYSICO-CHEMICAL CHARACTERISTICS, ISOTHERM AND THERMODYNAMICS ADSORPTION OF CHROMIUM IONS IN WASTEWATER

2020 ◽  
Vol 7 (3) ◽  
pp. 1-11
Author(s):  
I Nengah Simpen ◽  
I Made Sutha Negara ◽  
Sofyan Dwi Jayanto
Keyword(s):  
Active Sites ◽  
Crystal Size ◽  
Physical Adsorption ◽  
Low Cost ◽  
Chemical Characteristics ◽  
Bovine Bone ◽  
Chromium Ions ◽  
Physico Chemical ◽  
Freundlich Adsorption Isotherm ◽  
Surface Active

The adsorption characteristics of chromium ions in chrome electroplating wastewater on low cost adsorbent have been conducted. Adsorbent was prepared from bovine bone waste of NaOH activated at various concentrations (0.2 to 0.8 M). Its adsorption such as adsorption isotherms and adsorption thermodynamics as well as adsorbent physico-chemical characteristics (surface active sites, crystallinity and crystal size, surface morphology and elementals composition). The result showed that amount of adsorbent surface active sites increased because of NaOH activated, the highest at 0.4 M NaOH concentration (AT0.4 adsorbent). X-ray diffraction patterns of the adsorbents showed a wide peaks and crystal size as nanocrystalline. The surface morfology was stack of aglomerates and leached of Ca and Mg due to increase Na. The adsorption result of adsorbents to chromium ions showed that the highest adsorption ability on AT0.4 adsorbent. It was suitable for Freundlich adsorption isotherm model as physical adsorption and endothermic but the tendency to be spontaneous process.

scholarly journals Carbon Dioxide Photoreduction on the Bi2S3/MoS2 Catalyst

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 998 ◽  
Author(s):  
Kim ◽  
Kim ◽  
Do ◽  
Seo ◽  
Kang
Keyword(s):  
Carbon Dioxide ◽  
Light Absorption ◽  
Charge Separation ◽  
Effective Charge ◽  
Active Sites ◽  
Electron Excitation ◽  
Photocurrent Density ◽  
Catalytic Performance ◽  
Inorganic Materials ◽  
Composite Catalyst

The photocatalytic activity of a material is contingent on efficient light absorption, fast electron excitation, and control of the recombination rate by effective charge separation. Inorganic materials manufactured in unique shapes via controlled synthesis can exhibit significantly improved properties. Here, n-type Bi2S3 nanorods (with good optical activity) were wrapped with two-dimensional (2D) p-type MoS2 sheets, which have good light absorption properties. The designed p-n junction Bi2S3/MoS2 composite exhibited enhanced light absorption over the entire wavelength range, and higher carbon dioxide adsorption capacity and photocurrent density compared to the single catalysts. Consequently, the activity of the 1Bi2S3/1MoS2 composite catalyst for the photocatalytic reduction of carbon dioxide was more than 20 times higher than that of the single catalysts under visible-light irradiation at ≤400 nm, with partial selectivity for CO conversion. This is attributed to the p-n heterojunction Bi2S3/MoS2 composite designed in this study, the high light absorption of n-Bi2S3, accelerated electron excitation, and the electron affinity of the 2D sheet-p-MoS2, which quickly absorbed excited electrons, resulting in effective charge separation. This ultimately improved the catalytic performance by continuously supplying catalytically active sites to the heterojunction interfaces.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Efficient spatial charge separation in unique 2D tandem heterojunction CdxZn1−xIn2S4–CdS–MoS2 rendering highly-promoted visible-light-induced H2 generation

2021 ◽  
Vol 9 (1) ◽  
pp. 482-491
Author(s):  
Jiakun Wu ◽  
Bowen Sun ◽  
Hui Wang ◽  
Yanyan Li ◽  
Ying Zuo ◽  
...  
Keyword(s):  
Visible Light ◽  
Charge Separation ◽  
Effective Charge ◽  
Active Sites ◽  
H2 Generation ◽  
Highly Efficient ◽  
Spatial Charge

Unique 2D heterostructures CdxZn1−xIn2S4–CdS–MoS2 with effective charge separation, excellent light-harvest, and abundant active sites are highly-efficient for photocatalytic H2 evolution.

scholarly journals Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1316
Author(s):  
Vanessa Miglio ◽  
Chiara Zaccone ◽  
Chiara Vittoni ◽  
Ilaria Braschi ◽  
Enrico Buscaroli ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Water Solution ◽  
Synthesis Method ◽  
Textural Properties ◽  
Adsorption Properties ◽  
Water Soluble ◽  
Silica Monoliths ◽  
Physico Chemical ◽  
Gaseous Toluene ◽  
Mcm 41

This study focused on the application of mesoporous silica monoliths for the removal of organic pollutants. The physico-chemical textural and surface properties of the monoliths were investigated. The homogeneity of the textural properties along the entire length of the monoliths was assessed, as well as the reproducibility of the synthesis method. The adsorption properties of the monoliths for gaseous toluene, as a model of Volatile Organic Compounds (VOCs), were evaluated and compared to those of a reference meso-structured silica powder (MCM-41) of commercial origin. Silica monoliths adsorbed comparable amounts of toluene with respect to MCM-41, with better performances at low pressure. Finally, considering their potential application in water phase, the adsorption properties of monoliths toward Rhodamine B, selected as a model molecule of water soluble pollutants, were studied together with their stability in water. After 24 h of contact, the silica monoliths were able to adsorb up to the 70% of 1.5 × 10−2 mM Rhodamine B in water solution.

Cathodic Corrosion Activated Fe-based Nanoglass as Highly-Active and -Stable Oxygen Evolution Catalyst for Water Splitting

2021 ◽  
Author(s):  
Kaiyao Wu ◽  
Fei Chu ◽  
Yuying Meng ◽  
Kaveh Edalati ◽  
Qingsheng Gao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Amorphous Alloys ◽  
Precious Metal ◽  
Active Sites ◽  
Metal Free ◽  
Highly Active ◽  
Stable Oxygen ◽  
Surface Active

Transition metal-based amorphous alloys have attracted increasing attention as precious-metal-free electrocatalysts for oxygen evolution reaction (OER) of water splitting due to their high macro-conductivity and abundant surface active sites. However,...

scholarly journals Prepare a catalyst consist of rare earth minerals to denitrate via NH3-SCR

2020 ◽  
Vol 9 (1) ◽  
pp. 191-202
Author(s):  
Jian Wang ◽  
Chao Zhu ◽  
Baowei Li ◽  
Zhijun Gong ◽  
Zhaolei Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Active Sites ◽  
Nh3 Scr ◽  
Composite Oxides ◽  
Rare Earth Minerals ◽  
Denitrification Activity ◽  
Denitrification Reactor ◽  
Surface Active ◽  
Rare Earth Tailings ◽  
Treatment Step

AbstractTo research the roles of rare earth minerals in denitrification via the NH3-SCR, a mixture was made by certain ratio of rare earth concentrates and rare earth tailings, then treated by microwave roasting, and acids and bases to form a denitrification catalyst. The mineral phase structure and surface morphology of the catalyst were characterized by XRD, BET, SEM and EDS. The surface properties of the catalyst were tested by TPD and XPS methods, and the denitrification activity of the catalyst was evaluated in a denitrification reactor. The results showed that the denitrification efficiency increased up to 82% with complete processing. XRD, BET, SEM, and EDS spectrum analysis stated that the treated minerals contained cerium oxides and Fe−Ce composite oxides. The surface of the modified minerals became rough and porous, the surface area increased, and the surface-active sites were exposed. The results of NH3-TPD and NO-TPD showed that the catalyst surface could gradually adsorb more NH3 and NO after each step. XPS analysis indicated that there were more Ce3+, Fe2+, and lattice oxygen in rare earth minerals catalyst after each treatment step.

Enhanced photocatalytic H2 evolution over micro-SiC by coupling with CdS under visible light irradiation

2014 ◽  
Vol 2 (18) ◽  
pp. 6296-6300 ◽  
Author(s):  
Yuan Peng ◽  
Zhongnan Guo ◽  
Jingjing Yang ◽  
Da Wang ◽  
Wenxia Yuan
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Active Sites ◽  
Fine Tuning ◽  
Surface Activation ◽  
H2 Evolution ◽  
Effective Surface ◽  
Suitable Amount ◽  
Surface Active ◽  
Photocatalytic H2 Evolution

Fine-tuning surface activation of the micro-SiC catalyst via hybridizing a suitable amount of CdS to obtain effective surface active sites.

scholarly journals Morphological and Elemental Investigations on Co–Fe–B–O Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process

2021 ◽  
Author(s):  
Y. Popat ◽  
M. Orlandi ◽  
S. Gupta ◽  
N. Bazzanella ◽  
S. Pillai ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Water Oxidation ◽  
Active Sites ◽  
High Surface ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Active Species ◽  
Laser Deposition ◽  
Core Shell ◽  
Adsorption Sites

Abstract Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present Co–Fe–B–O coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to core–shell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with core–shell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized Co–Fe–B–O coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract

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