Development of a magnetic nanohybrid for multifunctional application

From immobile photocatalysis to efficient photoelectrochemical water splitting: A combined experimental and computational study

authored by
Tuhin Kumar Maji, Md Nur Hasan, Sangeeta Ghosh, Dirk Wulferding, Chinmoy Bhattacharya, Peter Lemmens, Debjani Karmakar, Samir Kumar Pal

Engineering of highly efficient nanomaterials with visible-light photocatalytic activity that are easily separable and recoverable from treated water is the ultimate goal in the ongoing research in the field of photocatalysis. On the other hand, photoelectrochemical (PEC) water splitting is one of the most promising technologies for hydrogen production using solar light with the aim to build sustainable, renewable and green energy. Hematite (α-Fe2O3) is a promising material that offers both enhanced photocatalytic activity and PEC activity due to its electronic band structure, high chemical stability, great abundance, and low cost. Despite these promising properties, the application of this system is limited due to its very fast electron-hole recombination rate and low carrier mobility. Here we report the design and synthesis of a newly envisioned nanohybrid based on Fe2O3 and phthalocyanine. The nanohybrid is an essential component to reduce the charge carrier recombination rate of the system. As a result of it, the nanohybrid shows higher photocatalytic activity and acts as a better photoanode material for photoelectrochemical water splitting. The formation of the nanohybrid is established using a picosecond resolved optical technique as well as by Raman Spectroscopy. Ab-initio study on the similar modeled system has been performed to investigate the insight of various physical properties. Electron microscopy reveals a distinct change of morphology in the nanohybrid compared to pristine one. While the photocatalytic activity of the nanohybrid increased 1.5 times with respect to the pristine system, the Photoelectrochemical activity almost doubles in the hybrid system. For real-world applications, our developed nanohybrid has been deposited on an extended surface of a stainless-steel metal mesh (size 2 cm × 2 cm, pore size 150 μm × 200 μm). Such a prototype active filter containing an immobilized photocatalyst shows significant chemical filtration of MB (by a degradation process) along with a physical filtration by separating the suspended particulates from the water. DFT + U calculation results show there is a possibility of higher charge separation from PC to Fe2O3, which is the reason for the higher activity in the hybrid systems.

External Organisation(s)
S N Bose National Centre for Basic Science
Technische Universität Braunschweig
Bhabha Atomic Research Centre
Indian Institute of Engineering Science and Technology
Journal of Photochemistry and Photobiology A: Chemistry
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Chemistry(all), Chemical Engineering(all), Physics and Astronomy(all)
Sustainable Development Goals
SDG 7 - Affordable and Clean Energy
Electronic version(s) (Access: Closed)