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

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 p...

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Bibliographic Details
Published inE3S Web of Conferences Vol. 287; p. 2009
Main Authors Mahpudz, Aishah, Lim, Siu Ling, Inokawa, Hitoshi, Kusakabe, Katsuki, Tomoshige, Ryuichi
Format Journal Article Conference Proceeding
LanguageEnglish
Published Les Ulis EDP Sciences 2021
Subjects
Aluminum
Anion exchange
Anion exchanging
Catalysts
Catalytic activity
Chemical reduction
Chemical synthesis
Citric acid
Cobalt
Hydrogen production
Hydrolysis
Hydroxides
Magnesium
Mass transport
Nanoclusters
Precursors
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Summary: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.
ISSN:2267-1242
2555-0403
2267-1242
DOI:10.1051/e3sconf/202128702009