scholarly journals Layered double hydroxide supported cobalt nanocluster: size control and the effect in catalytic hydrogen generation

2021 ◽  
Vol 287 ◽  
pp. 02009
Author(s):  
Aishah Mahpudz ◽  
Siu Ling Lim ◽  
Hitoshi Inokawa ◽  
Katsuki Kusakabe ◽  
Ryuichi Tomoshige
Keyword(s):  
Catalytic Activity ◽  
Layered Double Hydroxide ◽  
Hydrogen Generation ◽  
Chemical Reduction ◽  
Nitrogen Adsorption ◽  
High Ratio ◽  
Metal Nanoclusters ◽  
Catalytic Hydrogen ◽  
Double Hydroxide ◽  
Citrate Precursor

Synthesizing metal nanoclusters with diameters smaller than 5nm is challenging, but desirable because of the high ratio of surface area to interior atom. However, in this report it was achieved by utilizing magnesium-aluminium layered double hydroxide (Mg/Al-LDH) as a host for cobalt citrate anion precursor, which was later reduced into cobalt nanoclusters (Co-NC). Size of the Co-NC was controlled by changing the concentration of cobalt-citrate (Co-citrate) precursor during anion exchange. XRD and FTIR showed that Co-citrate precursor was successfully intercalated on the LDH while nitrogen adsorption/desorption isotherms confirmed that mesopores in the sample were formed after chemical reduction. Furthermore, TEM/STEM observations confirmed the formation of Co-NC. It was also verified that reducing the concentration of Co-citrate from 4mM to 0.5mM resulted in a reduction in the size of Co-NC from 4.4 to 1.3 nm. However, catalytic hydrogen generation from sodium borohydride (NaBH4) hydrolysis experiment indicated that catalytic activity decreased as the size of Co-NC decreases. This is mainly attributed to the limitation in mass transport within the interlamellar space of the smaller cluster LDH compared to the bigger one. Overall, Co-NC-LDH is a promising catalyst for NaBH4 hydrolysis. However, an optimum Co-NC size is critical for enhanced catalytic activity.

scholarly journals Physicochemical Study of 3,4-Dichlorophenoxyacetic Acid Intercalated into Hydrotalcite-Like Compound by Ion Exchanged Method

2016 ◽  
Vol 846 ◽  
pp. 440-447
Author(s):  
Sheikh Ahmad Izaddin Sheikh Mohd Ghazali ◽  
Siti Halimah Sarijo ◽  
Mohd Zobir Hussein
Keyword(s):  
Surface Area ◽  
Anion Exchange ◽  
Layered Double Hydroxide ◽  
Nitrogen Adsorption ◽  
Basal Spacing ◽  
Dichlorophenoxyacetic Acid ◽  
Exchange Method ◽  
Type Iv ◽  
Double Hydroxide ◽  
Adsorption Desorption

The intercalation of herbicide, 3,4-dicholorophenoxyacetic acid (3,4D), into zinc-aluminium-layered double hydroxide (LDH) for the formation of a new nanocomposite ZADX, was accomplished via anion exchange method. Due to the intercalation of 3,4D with LDH interlayer domain, basal spacing expanded from 8.9Å in the ZAL to 17.7-19.0 Å in the ZADX. The percentage loading of 3,4D in the ZADX is 51.4 % (w/w). The FTIR spectra of the nanocomposite shows resemblance peaks of the 3,4D and Zn-Al-layered double hydroxide indicating the inclusion of 3,4D into the layered double hydroxide. Surface area of the resulting nanocomposite increased from 1.3 to 7.14 m2g-1 with the nitrogen adsorption-desorption of type IV.

Heteropolyanion Substituted Layered Double Hydroxide as Recoverable Catalyst for the Oxidative Desulfurization of Simulated Fuel Oil and Diesel

2014 ◽  
Vol 672-674 ◽  
pp. 613-618
Author(s):  
Feng Li Yu ◽  
Yang Lu
Keyword(s):  
Catalytic Activity ◽  
Layered Double Hydroxide ◽  
Atmospheric Pressure ◽  
Removal Rate ◽  
Sulfur Removal ◽  
Oxidative Desulfurization ◽  
Fuel Oil ◽  
Simulated Fuel ◽  
Recoverable Catalyst ◽  
Double Hydroxide

Heteropolyanion substituted layered double hydroxide were synthesized and used as catalysts for oxidative desulfurization in simulated fuel oil (dibenzothiophene (DBT) inn-octane) or diesel. The catalysts are recoverable and operate with high conversion efficiency under mild conditions of atmospheric pressure and 60 °C in a biphasic system using peroxide hydrogen as oxidant and acetonitrile as extractant. Zn9Al3(OH)24PW12O40(ZnAlPW), Zn9Al3(OH)24PMo12O40(ZnAlPMo) and Zn12Al4(OH)32SiW12O40(ZnAlSiW) were identified as effective catalysts for the oxidative removal of DBT from simulated fuel oil. The order of decreasing catalytic activity is ZnAlPMo > ZnAlPW > ZnAlSiW. The results show that the best catalysts, ZnAlPMo, attained to a DBT conversion of nearly 100%. All the catalysts can be readily recycled by filtration after use. The recoverable ZnAlPMo retains nearly the same catalytic activity as the fresh. ZnAlPMo was found to exhibit an ideal catalytic activity in oxidative desulfurization of diesel with a total sulfur removal rate of 91.8%.

Calcined Ni—Al layered double hydroxide as a catalyst for total oxidation of volatile organic compounds: Effect of precursor crystallinity

2007 ◽  
Vol 61 (2) ◽  
Author(s):  
Z. Mikulová ◽  
P. Čuba ◽  
J. Balabánová ◽  
T. Rojka ◽  
F. Kovanda ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrothermal Treatment ◽  
Layered Double Hydroxide ◽  
Mixed Oxides ◽  
Slight Effect ◽  
Total Oxidation ◽  
Volatile Organic ◽  
Double Hydroxide ◽  
Short Time ◽  
Oxidation Of Ethanol

AbstractThe effect of hydrothermal treatment on properties (crystallinity, porous structure, reducibility, acidity, basicity, and catalytic activity and selectivity in toluene and ethanol total oxidation) of Ni—Al layered double hydroxide precursors and related mixed oxides was examined. The hydrothermal treatment increased considerably both the content of crystalline phase and LDH crystallite size. On the other hand, only a slight effect of the precursor hydrothermal treatment on crystallinity of the related Ni—Al mixed oxides obtained by calcination at 450°C was observed. The reducibility of NiO particles appeared to be hindered considerably compared to the reducibility of pure NiO. Catalytic activity of the Ni—Al mixed oxides prepared from the precursors hydrothermally treated for a short time (4 h) was the highest. The highest amount of acetaldehyde formed during the total oxidation of ethanol, i.e. the worst selectivity was found for the calcined Ni—Al LDH without hydrothermal treatment.

scholarly journals Efficient degradation of organic pollutants by peroxymonosulfate activated with MgCuFe-layered double hydroxide

RSC Advances ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 2284-2291 ◽  
Author(s):  
Jianyao Zhu ◽  
Zhiliang Zhu ◽  
Hua Zhang ◽  
Hongtao Lu ◽  
Yanling Qiu
Keyword(s):  
Catalytic Activity ◽  
Layered Double Hydroxide ◽  
Organic Pollutants ◽  
High Catalytic Activity ◽  
Reactive Radicals ◽  
Double Hydroxide

MgCuFe-layered double hydroxide exhibited high catalytic activity to activate peroxymonosulfate for degradation of organic pollutants. SO4˙− and ·OH are the main reactive radicals involved in the degradation of organic pollutants.

Highly efficient photocatalytic hydrogen generation by incorporating CdS into ZnCr-layered double hydroxide interlayer

RSC Advances ◽  
2015 ◽  
Vol 5 (8) ◽  
pp. 5823-5829 ◽  
Author(s):  
Guohua Zhang ◽  
Bizhou Lin ◽  
Weiwei Yang ◽  
Shaofeng Jiang ◽  
Qianru Yao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Layered Double Hydroxide ◽  
Hydrogen Generation ◽  
Cds Nanoparticles ◽  
Highly Efficient ◽  
Photocatalytic Hydrogen Generation ◽  
Double Hydroxide

Incorporating CdS nanoparticles into the interlayer of ZnCr–LDH nanosheets led to the formation of CdS-pillared ZnCr–LDH nanohybrid, which exhibited superior photocatalytic hydrogen-generation performance from water splitting.

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