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Associate Professor Dr. Montree Sawangphruk

Chemical Engineering
School of Energy Science and Engineering (ESE)
Tel. +66(0) 33 014251
Email montree.s@vistec.ac.th
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Advanced Layered Double Hydroxide Materials

 

Research Overview

LDH materials such as Co(OH)2, Ni(OH)2 and their composites with graphene materials are of interest. These LDH materials have several advantages such as low-cost, earth abundance, good redox property. Therefore, it is possible to utilize them in energy storage applications. Our group focuses on the development of the supercapacitors, photo-charging supercapacitors and water splitting (H2/O2 evolutions).

BACKGROUND

Layered double hydroxide (LDH) is very interesting because it is new materials cluster that need fundamental research for gaining better understanding. Especially, their properties in electronic, photonic, mechanic and magnetic are tremendous importance for their application. LDH materials are classified as 2D ionic lamellar structure that contains anions (CO32-, Cl-, SO42- and etc.) between positive layers brucite-like structure. The existence of these anions significantly affects their structure and crystalline phase formation, especially, d-spacing. Therefore, their properties of LDH depend on their structure. Moreover, LDH materials also applied in several research fields such as thin film, catalyst, electrode materials (supercapacitors, Li ion battery, and dye-sensitized solar cells), hybrid magnets and bioinorganic hybrid materials.

Photo-charging supercapacitors

Co(OH)2 film electrode was prepared with electrodepositon technique and then characterized with several techniques such as FESEM, UV-Visible spectrometer, electrochemical technique and etc. We found that the electrodeposited Co(OH)2 shows the layer-like structure and also acts as photoactive material. The optical spectrum of Co(OH)2 was calculated to find the band gap, is about 1.85 eV. In our work, Cobalt hydroxide Co(OH)2 is a candidate to be applied in supercapacitor because it has large interlayer spacing (more than 7 Å in α-phase and 4.6 Å in β-phase), excellent electrochemical redox activity, earth-abundant catalyst, high surface area. More interestingly, Co(OH)2 has been report that it has high theoretical specific capacitance (ca. 3400 F/g). More interestingly, we found that Co(OH)2 is photoactive material and also expected to charge with light. From cyclic voltammetry (CV), it clears that both the Co(OH)2 cell under illumination (red, blue and green lines) shows higher current than the cell in dark (black line). This suggests that the performance of Co(OH)2 supercapacitor is improved with light illumination. Co(OH)2 is able to charge under light illumination and we called “Photo-charging supercapacitor”. This mechanism in charge and discharge can be explained according to Fig.(d). As Co(OH)2 is semi-conductor and photoactive material, it can be activated with light. Electron can jump to conduction band (CB) and transfer to another electrode while the hole in valence band (VB) can trap hydroxyl ions (KOH electrolyte). When Co(OH)2 accept hydroxyl ions, it can form CoO(OH) for charging and this process is reversible for discharging.

Supercapacitors

Ni(OH)2 has attracted much attention owing to its high theoretical specific capacitance (2,082 F g-1). Some pervious report even showed unusual high specific capacitances over the theoretical one. Generally, there are two phases of Ni(OH)2 including α-Ni(OH)2 and β-Ni(OH)2, which have been used as the supercapacitor electrodes. However, in this work we have found after long cycling (>3000 cycles) of α-Ni(OH)2-based supercapacitors, the α-Ni(OH)2 is transformed to β-Ni(OH)2 storing less charges since it has too narrow interlayer spacing (4.5 Å) leading to poor capacity retention.
 


Another LDH material, α-Co(OH)2 was electrodeposited on reduced graphene oxide-coated carbon fiber paper (rGO/CFP) using a chronoamperometry at -0.5 V vs. Ag/AgCl. It was found that the concentrated alkaline electrolytes (i.e., 3-6 M [OH-]) can strip off and/or deform the porous structure of the α-Co(OH)2 deposited on rGO/CFP leading to poor charge storage capacity. 1 M [OH-] was found to be a suitable electrolyte concentration providing high specific capacitance (1096 F g-1 at 1.8 A g-1) without the deformation of the porous α-Co(OH)2 structure after testing. Morphological and electrochemical analyses of the α-Co(OH)2/rGO/CFP electrodes suggest that the effect of the alkaline electrolyte concentration plays a major role to the charge storage performance of α-Co(OH)2-based supercapacitors.
 


Moreover, layered double cobalt hydroxides (LDCHs) are also increased the performance of supercapacitor with Ag nanoparticles. In our work, Ag nanoparticles are for the first time incorporated to the LDCHs via a simple one-step co-electrodeposition process. A simultaneous growing Ag-doped layered double cobalt hydroxide (Ag-LDCHs) nanosheets on a reduced graphene oxide (rGO)-coated functionalized carbon fiber paper (f-CFP) was carried out in 1 mM AgNO3 + 100 mM Co(NO3)2 in 0.5 M NaNO3 at -0.5 V vs. Ag/AgCl for 10 min. Ag-LDCHs consist of high porosity LDCHs decorated with silver nanoparticles. Silver doping can give rather high areal capacitance of 1,161 mF cm-2 at a scan rate of 10 mV s-1 in 1 M NaOH aqueous electrolyte. The device exhibits ultrahigh maximum specific power of 20.31 kW kg-1 and specific energy of 114.37 Wh kg-1 with a wide operating voltage of 3.8 V. The incorporation of Ag into LDCH structures significantly enhances electrical conductivity, ion transportation and reversibility of the material.

Water splitting (H2 and O2 evolutions)

LDH materials such as Co(OH)2 and Ni(OH)2 are expected to apply in H2 and O2 evolutions or well known “water splitting”. For semi-conductive materials, it has the potential in photo-electrolysis reaction. Therefore, these materials were used as photoactive material in photoelectrochemical water splitting. For water splitting, when a photoactive material is excited with light, hole (h+) state can generate O2 gas (O2 evolution) while the excited electron (e-) can produce H2 gas (H2 evolution). The amount of semi-conductive materials has been studied for photoelectrochemical water splitting. In our work, we found that Co(OH)2 a photoactive material and its band gap is about 1.85 eV. It is possible to apply in O2 evolution and then improve the performance of O2 evolution with light illumination. Moreover, Ni(OH)2 and Ag-Co(OH)2 are also candidate to study about O2 evolution. All of experiments are in progress.
 

Selected Publications

Steingrube S., Timme M., Wörgötter F., Manoonpong P.Nature Physics 6, 224-230 (2010).
Manoonpong P., Parlitz U., Wörgötter F. Front.Neural Circuits 7(12), DOI: 10.3389/fncir.2013.00012 (2013).
Goldschmidt D., Wörgötter F., Manoonpong P.Front. Neurorobot. 8(3), DOI: 10.3389/fnbot.2014.00003 (2014).
Xiong X., Wörgötter F., Manoonpong P.Rob Auton Syst. 62(12), 1777-1789 (2014).
Dasgupta S., Wörgötter F., Manoonpong, P.Front. Neural Circuits 8(126), DOI: 10.3389/fncir.2014.00126 (2014).
Grinke E., Tetzlaff C., Wörgötter F., Manoonpong P.Front. Neurorobot. 9(11), DOI: 10.3389/fnbot.2015.00011 (2015).
Dasgupta S., Goldschmidt D., Wörgötter F., Manoonpong P.Front. Neurorobot. 9(10), DOI: 10.3389/fnbot.2015.00010 (2015).
Ren G., Chen W., Dasgupta S., Kolodziejski C., Wörgötter F., Manoonpong P.Information Sciences 294, 666-682 (2015).
Xiong X., Wörgötter F., Manoonpong P.IEEE Trans Cybern. 46(11), 2521-2534 (2016).
Manoonpong P., Petersen D., Kovalev A., Wörgötter F., Gorb S., Spinner M., Heepe L.Scientific Reports 6(39455), DOI: 10.1038/srep39455 (2016).
Goldschmidt D., Manoonpong P., Dasgupta S.Front. Neurorobot. 11(20), DOI: 10.3389/fnbot.2017.00020 (2017).
Nachstedt T., Tetzlaff C., Manoonpong P.Front. Neurorobot. 11(14), DOI: 10.3389/fnbot.2017.00014 (2017)

Research Group Members:

Dr. Montree Sawangphruk (Assistant Professor)
Dr. Saran Kalasina (Postdoctoral Research Fellow)
Ms. Atiweena Krittayavathananon
Mr. Poramane Chiochan
Mr. Chan Tanggarnjanavalukul
Ms. Montakan Suksomboon
Mr. Nutthaphon Phattharasupakun
Ms. Juthaporn Wutthiprom
Ms. Siriroong Kaewruang
Mr. Jakkrit Khuntilo
Ms. Phansiri Suktha
Mr. Pawin Iamprasertkun
Mr. Tanut Pettong
Ms. Pichamon Sirisinudomkit
 

International Research Collaborator:

Prof. John S Foord
University of Oxford