R. Mithun Prakash

Bio: R. Mithun Prakash is an academic researcher from Jain University. The author has contributed to research in topics: Photocatalysis & Methanol. The author has an hindex of 2, co-authored 6 publications receiving 19 citations.

Ferroelectric semiconductors for photocatalytic energy and environmental applications

Abstract: Photocatalysis is a multifaceted phenomenon that can be used for various applications, which include pollutants degradation, organic synthesis, H2 production, CO2 reduction, N2 fixation, antimicrobial applications, and biomass conversion. However, materials are key ingredients to achieve an effective photocatalytic conversion. The meticulous understanding of photocatalytic process reveals that the band edge position, bandgap energy, recombination process, and surface reactions are the four fundamental parameters that need to be controlled to enhance the efficiency of a photocatalyst. In this direction, ferroelectric materials have drawn significant interests due to their internal electrical field, surface polarization properties, and effective band-bending process, which largely govern the abovementioned properties of a photocatalyst. The phenomenon of ferroelectrics essentially helps to reduce the charge recombination possibilities in the system and effortlessly promotes the excited charge carriers to the surface with active sites. However, most of the ferroelectric photocatalysts are ultraviolet light–driven and therefore it has the scope for the bandgap reduction strategies by means of controlling particle size, doping, composite formations, etc. In this context, this chapter intends to provide insights into the various ferroelectric materials that can be used for photocatalytic applications, working mechanism, and their applications in photocatalysis along with a conclusion that highlights the future prospects in the field of ferroelectric photocatalysis.

Band structuring engineering in titanium oxynitrides for the visible light driven photocatalytic applications

Abstract: Herein, we report the band structure engineering in titanium oxynitrides by annealing the titanium nitrides (TiN) in the ambient conditions at different temperatures. The parametric studies via increasing the annealing temperature from 450 to 650 °C (3 h) revealed the formation kinetics of oxynitride system. The TiNannealed at 450 and 550 °C showed the XRD peaks corresponding to titanium oxynitride, and mixed phases of anatase, rutile TiO2, whereasthe TiN annealed at 650 °C was found to be pure rutile phase of TiO2. Interestingly, the mixed phase-TiON(550 °C) showed the well-reduced band gap energy and visible light activity as compared to the other samples.

Recent Developments in the Use of Heterogeneous Semiconductor Photocatalyst Based Materials for a Visible-Light-Induced Water-Splitting System—A Brief Review

Abstract: Visible-light-driven photoelectrochemical (PEC) and photocatalytic water splitting systems featuring heterogeneous semiconductor photocatalysts (oxynitrides, oxysulfides, organophotocatalysts) signify an environmentally friendly and promising approach for the manufacturing of renewable hydrogen fuel. Semiconducting electrode materials as the main constituents in the PEC water splitting system have substantial effects on the device’s solar-to-hydrogen (STH) conversion efficiency. Given the complication of the photocatalysis and photoelectrolysis methods, it is indispensable to include the different electrocatalytic materials for advancing visible-light-driven water splitting, considered a difficult challenge. Heterogeneous semiconductor-based materials with narrower bandgaps (2.5 to 1.9 eV), equivalent to the theoretical STH efficiencies ranging from 9.3% to 20.9%, are recognized as new types of photoabsorbents to engage as photoelectrodes for PEC water oxidation and have fascinated much consideration. Herein, we spotlight mainly on heterogenous semiconductor-based photoanode materials for PEC water splitting. Different heterogeneous photocatalysts based materials are emphasized in different groups, such as oxynitrides, oxysulfides, and organic solids. Lastly, the design approach and future developments regarding heterogeneous photocatalysts oxide electrodes for PEC applications and photocatalytic applications are also discussed.

Decay time of polaron photoluminescence in congruent lithium niobate

Abstract: The intensity, the peak wavelength and the decay time of polaron photoluminescence in congruent lithium niobate are measured versus temperature from 77 K to 290 K. The radiative relaxation shows quasi athermal behaviour (τR ≈ 9 µs) whereas the nonradiative relaxation follows arrhenius law with activation energy of 220 meV. The crossing point between radiative and nonradiative lifetimes is about 210 K. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)