Vibrational spectroscopic characterization of growth bands in Porites coral from South China Sea

Song, Young-Chae; Yu, Kefu; Ayoko, Godwin A.; Frost, Ray L.; Shi, Quan; Feng, Yuexing; Zhao, Jian‐xin

doi:10.1016/j.saa.2013.04.049

Cited by 3 publications

(3 citation statements)

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“…The use of IR and Raman (IR/R) spectroscopic techniques in gemology is well documented . These techniques have been used as ideal non‐invasive tools suitable to study composition of mineral and organic objects, including amber, coral, mollusk shells and pearl pigments.…”

Section: Introductionmentioning

confidence: 99%

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Kupka

Buczek

Broda

et al. 2016

J Raman Spectroscopy

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Pigments from red coral (Corallium rubrum) and African snail (Helixia aspersa) shell were studied non-invasively using Raman spectroscopy with 1064-nm laser beam. The two observed bands because of organic pigments confined in biomineralized CaCO 3 matrix at about 1500 and 1100 cm À1 were assigned to ν(C¼C) and ν(C-C), respectively. Both signals originate from polyene(s) of largely unknown structure, containing several conjugated C¼C bonds. The small peak at 1016 cm À1 in the Raman spectrum of coral pigment was assigned to in-plane -CH 3 rocking or structural deformation of polyene chain because of spatial confinement in the mineral matrix. The organic pigments in red coral and snail shell were present in inorganic matrix containing aragonite (shell) and calcite (coral). In addition, using Raman spectroscopy, it was observed that aragonite was replaced by calcite as result of healing damaged parts of snail shell. This is an important finding which indicates a great potential of nondestructive Raman spectroscopy instead of X-ray technique, as a diagnostic tool in environmental studies. To support analysis of the observed Raman spectra detailed calculations using density functional theory (DFT with B3LYP and BLYP density functionals) on structure and vibrations of model all-trans polyenes were undertaken. DFT calculated C¼C and C-C stretching frequencies for all-trans polyenes containing from 2 to 14 C¼C units were compared with the observed ν(C¼C) and ν(C-C) band positions of the studied coral and shell. Individual correction factors were used to better match theoretical wavenumbers with observed band positions in red coral and African snail. It was concluded that all-trans polyene pigments of red coral and dark parts of African snail shell contain 11-12 and 14 C¼C double bond units, respectively. However, Raman spectroscopy cannot produce any clear information on the presence and nature of the end-chain substituents in the studied pigments.

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Section: Introductionmentioning

confidence: 99%

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Kupka

Buczek

Broda

et al. 2016

J Raman Spectroscopy

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“…Further, the corresponding p 5 and p 2 peaks found at 257 and 362 cm −1 were assigned to the various vibrational modes of FeO 6 octahedra [48,49] . Contrarily, the p 4 (299 cm −1 ) band can be attributed to a lattice vibration of CaCO 3 in the vaterite phase [50] . Note that the band p 7 at around 228 cm −1 in both in‐situ samples derives from ice, [51] which remained on the sample surface during freeze quenching at cryogenic temperatures.…”

Section: Resultsmentioning

confidence: 88%

“…[48,49] Contrarily, the p4 (299 cm À 1 ) band can be attributed to a lattice vibration of CaCO 3 in the vaterite phase. [50] Note that the band p7 at around 228 cm À 1 in both in-situ samples derives from ice, [51] which remained on the sample surface during freeze quenching at cryogenic temperatures.…”

Section: Ex-situ and In-situ Post Ca-characterizationsmentioning

confidence: 96%

An Intermetallic CaFe₆Ge₆ Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction

et al. 2022

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Based on the low-cost and relatively high catalytic activity, considerable efforts have been devoted towards developing redox-active transition metal (TM)-oxygen electrocatalysts for the alkaline oxygen evolution reaction (OER) while the role of redox-inactive alkaline earth metals has often been neglected in OER. Herein, for the first time, we developed a novel ternary intermetallic CaFe 6 Ge 6 precatalyst, whose surface rapidly transforms into a porous ultrathin CaÀ FeÀ O heteroshell structure during alkaline OER through the oxidative leaching of surficial Ge. Benefiting from synergistic effects, this highly efficient OERactive material with distinct CaÀ FeÀ O layers has a large electrochemical surface area and more exposed active Fe sites than a Ca-free FeO x phase. Also, the presence of Ca in CaÀ FeÀ O is responsible for the enhanced transport and activation of hydroxyls and related OER reaction intermediate as unequivocally illustrated by a combination of quasi in-situ Raman spectroscopy and various ex-situ methods.

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Sclerites of the soft coral Ovabunda macrospiculata (Xeniidae) are predominantly the metastable CaCO3 polymorph vaterite

et al. 2021

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Vibrational spectroscopic characterization of growth bands in Porites coral from South China Sea

Cited by 3 publications

References 38 publications

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

An Intermetallic CaFe₆Ge₆ Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction

Sclerites of the soft coral Ovabunda macrospiculata (Xeniidae) are predominantly the metastable CaCO3 polymorph vaterite

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Vibrational spectroscopic characterization of growth bands in Porites coral from South China Sea

Cited by 3 publications

References 38 publications

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

An Intermetallic CaFe6Ge6 Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction

Sclerites of the soft coral Ovabunda macrospiculata (Xeniidae) are predominantly the metastable CaCO3 polymorph vaterite

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An Intermetallic CaFe₆Ge₆ Approach to Unprecedented Ca−Fe−O Electrocatalyst for Efficient Alkaline Oxygen Evolution Reaction