ars.els-cdn.com€¦ · Web viewSanjit Saha,a,b Suman Chhetri,a,b Partha Khanra,c Pranab Samanta,a,b Hyeyoung Koo,d Naresh Chandra Murmua,b and Tapas Kuila a,b* a Surface Engineering

Supplementary material

In-situ hydrothermal synthesis of MnO2/NiO@Ni hetero structure

electrode for hydrogen evolution reaction and high energy

asymmetric supercapacitor application

Sanjit Saha,a,b Suman Chhetri,a,b Partha Khanra,c Pranab Samanta,a,b Hyeyoung Koo,d Naresh

Chandra Murmua,b and Tapas Kuila a,b*

a Surface Engineering & Tribology Division, CSIR-Central Mechanical Engineering Research

Institute, Durgapur -713209, India

b Academy of Scientific and Innovative Research (AcSIR), CSIR-CMERI Campus,

Durgapur-713209

c Soft Innovative Materials Research Centre, Korea Institute of Science and Technology

(KIST), Jeonbuk 565905, South Korea

d Soft Innovative Materials Research Centre, Institute of Advanced Composite Materials,

Korea Institute of Science and Technology (KIST), Jeonbuk 565905, South Korea

*Correspondence to: Tapas Kuila, E-mail: [email protected]; Tel: +91 9647205077

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Sample preparation for characterization

Small pieces of MnO2/NiO@Ni were directly used for the FE-SEM analysis.

MnO2/NiO@Ni was scratched to collect the powder sample of MnO2/NiO composite.

The collected powder was used for XRD and FT-IR analysis. A thin pellet (thickness ~

xx) was prepared with the collected powder for the electrical conductivity

measurement. The dispersion of MnO2/NiO powder in distilled water was used for the

UV-vis spectroscopy measurement. The MnO2/NiO powder was dispersed in an

ethanol by 30 min ultra sonication and the dispersion was drop casted onto a fresh

lacey carbon copper grid for the TEM analysis.

The MnO2/NiO@Ni was directly used for the electrochemical measurement. Three

electrode measurements were carried out by using 3 cm × 0.5 cm MnO2/NiO@Ni as

working electrode. In case of two-electrode measurement, the MnO2/NiO@Ni was cut

into a circle shape with a diameter of 1 cm.

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Figure S1 XRD pattern of MnO2/NiO.

Figure S2 FT-IR spectra of MnO2/NiO.

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Figure S3 UV-visible absorption spectra of MnO2/NiO. The inset view of the same

shows the (αhν)2 vs. hν plot.

Figure S4 The variation of conductivity of MnO2/NiO with different temperature.

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Figure S5 CV of MnO2/NiO at 1 M aqueous KOH electrolyte.

Figure S6 Comparative CV of bare Ni-foam and MnO2/NiO@Ni at 1 M Na2SO4

electrolyte.

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Fig. S7 (a) TEM and (b) SAED pattern image of TRG.

Fig. S8 Raman spectra of GO and TRG. TRG has two characteristic peaks, G peak

(1574 cm-1) and 2D peak (2676 cm-1). The 2D peak is associated with the band

structure of the graphene layers originating from the two phonon double resonance.1, 2

The D band (1348 cm-1) indicates the presence of defects within the graphitic

structure.1 The formation of sp3 carbon within the sp2 network can generate the defect.

The degree of disorder in a sp2 network structure of graphene can be measured by ID/IG

ratio.1

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Figure S9 CD profile of ASC recorded at different cycles.

[1] T. Kuila, P. Khanra, N. H. Kim, S. K. Choi, H. J. Yun and J. H. Lee,

Nanotechnology 24 (2013) 364706.

[2] S. Bose, T. Kuila, A. K. Mishra, N. H. Kim and J. H. Lee, Nanotechnology 22

(2011) 405603.

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