Ashok K. GANGULI Seminar

Design of nanoheterostructures for photoelectrochemical applications

Director, Indian Institute of Science, Education & Research (IISER), Berhampur (India)

Friday, May 26, 2023 – 2:30 p.m.

University of Rennes 1 – Beaulieu Campus
Building 10B, Grandjean Amphitheater


Solid State Chemistry and Materials team

Pr Ashok Ganguli (CV attached) will travel to France from May 20th, 2023 to June 4th, 2023 as part of CEFIPRA to participate in the 70th Scientific Council of CEFIPRA, scheduled in Bordeaux from May 22 to 24, 2023. The visit of Pr Ashok Ganguli at ISCR will provide an excellent opportunity to discuss potential areas of collaboration with him.

He will be at ISCR on Friday May 26th in the morning. If you wish to discuss with him, the contact is Stéphane Cordier.

His topics of research deal with:
1. Nanostructured materials for efficient photocatalysis and photoelectrochemical conversion.
2. Microemulsion routes to controlled growth of nanostructures
3. Recent studies in metal chalcogenide superconductors

Abstract

Coupling of wide band gap semiconductor such as ZnO, NaNbO3 with narrow band gap semiconductors like Ag2S, In2S3, CuInS2 etc. (which act as sensitizers) forms efficient heterostructures for the separation of photogenerated charge carriers and makes it a good candidate for visible-light photocatalysis.1 CdS is a visible-light semiconductor having a band gap of 2.4 eV, appropriate band-edge positions, and outstanding charge-transfer rates, but the applications of the CdS semiconductor are limited due to its fast charge-carrier recombination and photocorrosion. We have reported the conjugation of CdS supraparticles with graphene which provides higher charge separation and slower carrier recombination rates compared to bare CdS supraparticles2. In another report we have adopted a strategy to modify the CdS photoanode by the incorporation of a hole scavenger, cobalt phosphate (CoPi), and an electron scavenger, multi-walled carbon nanotubes (CNTs), which would lead to the simultaneous extraction of electron−hole pairs generated in CdS. In case of CdS−CNT−CoPi composite, it shows a 90-fold enhancement in photocurrent compared to CdS at 1.23 V versus the reversible hydrogen electrode3. Cu2WS4-FeOOH-MWCNT type ternary heteristructures have been investigated4 for understanding the charge carrier transfer from Cu2WS4 to multi-walled carbon nanotubes (MWCNT) and FeOOH. The photo-electrochemical (PEC) water oxidation is expedited by CNT for better photo-anodic performance. BiVO4 is a promising photoanode material for photoelectrochemical water splitting applications. We have reported5 Mn doped BiVO4 to improve the charge-transport properties of the catalyst. Addition of Mn enables forbidden d-d transitions which is utilized to slow down the charge-carrier recombination and increase efficiency. Cu2O has been used as a photocatalyst and it holds promise being non-toxic and abundantly available on earth. However, due to lower band edge of Cu2O, it gets oxidized easily and its high recombination rate of electron-hole pairs which lowers its activity. We have used MoS2/rGO as a co-catalyst with Cu2O to suppress the recombination rate of the photogenerated charge carrier in Cu2O as well as to inhibit the photocorrosion and provide an electron rich environment to the system6.The ternary composite shows much higher photoactivity as compared with the bare one. In another report we have designed VS4-MoS2-rGO based composite which helps to suppress the charge carrier recombination rate as well as photocorrosion in VS4 and provides better photoelectrochemical activity and stability of the photo-catalyst7 .

References

  1. S. Kumar et al, Inorg. Chem. 2018, 57, 15112.
  2. K. Ojha, T. Debnath, P. Maity, M. Makkar, S. Nejati, K. V. Ramanujachary, P. K. Chowdhury, H. N. Ghosh, A. K. Ganguli, J. Phys. Chem. C 2017, 121, 6581.
  3. P. Dagar, N. Ghorai, K. Ojha, H. N. Ghosh, A. K. Ganguli, J. Phys. Chem. C 2021, 125, 8684.
  4. P. Dagar, N. Ghorai,  H. N. Ghosh, A. K. Ganguli, J. Phys. Chem. C (communicated) (2022).
  5. P. Dagar, S. Kumar, A. K. Ganguli, New J. Chem. 2022, 46, 2875.
  6. S. Tiwari, S. Kumar, A. K. Ganguli, J. Photochem. Photobiol. A Chem. 2022, 424, 113622.
  7. S. Tiwari, N. Jhamb, S. Kumar, A. K. Ganguli, ChemNanoMat 2022, DOI 10.1002/cnma.202100429.

 

Contact: Stéphane Cordier (3 65 36) – stephane [dot] cordieratuniv-rennes [dot] fr