Hydrothermally synthesized Na₂Ti₃O₇ nanotube–V₂O₅ heterostructures with improved visible photocatalytic degradation and hydrogen evolution - Its photocorrosion suppression

Vattikuti, S.V. Prabhakar,Reddy, Police Anil Kumar,NagaJyothi, P.C.,Shim, Jaesool,Byon, Chan Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.740 No.-

<P><B>Abstract</B></P> <P>There is still a need to prepare heterostructure photocatalysts with high activity and recyclability but without using precious metals to reduce the cost of photocatalysts. Thus, a facile and simple method for the synthesis of a Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst via hydrothermal synthesis is reported herein. The chemical composition, morphology, and structural features of the photocatalyst were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), N<SUB>2</SUB> adsorption–desorption specific surface area analysis (BET), and diffuse reflectance absorption (DRS) methods. It was observed that the specific surface area of the Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst increased with the incorporation of V<SUB>2</SUB>O<SUB>5</SUB>. The Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst was then used for the removal of rhodamine B (RhB) under simulated solar light irradiation. The Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst revealed excellent photocatalytic activity and photodegradation kinetics as compared to pristine Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotubes and V<SUB>2</SUB>O<SUB>5</SUB> photocatalysts. Furthermore, both the photoactivity and long-term stability of the Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst were superior to those of the pristine Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotubes and V<SUB>2</SUB>O<SUB>5</SUB> photocatalysts. The excellent photocatalytic performance of the Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> nanotube–V<SUB>2</SUB>O<SUB>5</SUB> heterostructure photocatalyst can be ascribed to its high specific surface area (283.71 m<SUP>2</SUP>g<SUP>−1</SUP>), mesoporous structure, highly dispersed V<SUB>2</SUB>O<SUB>5</SUB> nanoparticles, and hindrance of electron–hole pair recombination of Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> due to the V<SUB>2</SUB>O<SUB>5</SUB> incorporation, which is proven by the photoelectrochemical results, including photocurrent and electron impendence spectroscopy results. In addition, during the study of photocatalytic hydrogen evolution, the hydrogen yield of the Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB>/V<SUB>2</SUB>O<SUB>5</SUB> nanocomposite was 1.83 times that of pristine Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB>, which also exhibited excellent photocatalytic activity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Heterojunction of Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> NTs/V<SUB>2</SUB>O<SUB>5</SUB> NPs was developed via hydrothermal method. </LI> <LI> Visible photocatalytic RhB degradation studies were performed over Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> NTs/V<SUB>2</SUB>O<SUB>5</SUB> NPs. </LI> <LI> Improved degradation efficiency was observed over Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> NTs/V<SUB>2</SUB>O<SUB>5</SUB> NPs when compared to pristine Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> NTs. </LI> <LI> V<SUB>2</SUB>O<SUB>5</SUB> NPs were successfully utilized as cocatalyst for pollutant degradation. </LI> <LI> Charge recombination was diminished in the Na<SUB>2</SUB>Ti<SUB>3</SUB>O<SUB>7</SUB> NTs by the addition of V<SUB>2</SUB>O<SUB>5</SUB> NPs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Effect of annealing temperature on the electrical and structural properties of V/p-GaN Schottky structures

Padma, R.,Nagaraju, G.,Rajagopal Reddy, V.,Choi, Chel-Jong Elsevier 2016 THIN SOLID FILMS - Vol.598 No.-

<P><B>Abstract</B></P> <P>The electrical and structural properties of V/p-GaN Schottky barrier diode (SBD) have been investigated as a function of annealing temperature. The Schottky barrier height (SBH) of the as-deposited contact is found to be 0.82eV (<I>I–V</I>) and 1.10eV (<I>C–V</I>). However, it is noted that the SBH increases for the contact annealed at 400°C and the values are 0.94eV (<I>I–V</I>) and 1.21eV (<I>C–V</I>). Further, with increasing annealing temperature up to 500°C, the SBH decreases to 0.92eV (<I>I–V</I>) and 1.19eV (<I>C–V</I>). Also, the rectification ratio of the V/p-GaN SBD is evaluated for as-deposited and annealed contacts. The electrical parameters of the V/p-GaN SBD are also discussed with Cheung's and Norde functions. It is noted that the interface state density decreases upon annealing at 400°C and then slightly increases after annealing at 500°C. Results reveal that the superior electrical characteristics are obtained for the contact annealed at 400°C. The electrical results are also correlated with the interfacial microstructure of the contacts. The AES and XRD results reveal that the formation of nitride phases at the interface may be the reason for the increase of SBH after annealing at 400°C. The formation of gallide phases at the interface may be reason for the decrease in the SBH.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Annealing effects on electrical and structural properties of V/p-GaN SBD are studied. </LI> <LI> Maximum barrier height is obtained on V/p-GaN SBD upon annealing at 400°C. </LI> <LI> Interface state density decreases with increasing annealing temperature up to 400°C. </LI> <LI> Electrical results are correlated with the interfacial microstructure of the contacts. </LI> <LI> Nitride interfacial phases are responsible for increase in BH after annealing at 400°C. </LI> </UL> </P>

Structural and optical properties of vanadium doped SnO₂ nanoparticles with high photocatalytic activities

Reddy, Ch.V.,Babu, B.,Vattikuti, S.V.P.,Ravikumar, R.V.S.S.N.,Shim, J. Elsevier [etc.] 2016 Journal of luminescence Vol.179 No.-

Vanadium (0.01, 0.03 and 0.05mol%) doped SnO<SUB>2</SUB> nanoparticles have been synthesized using combustion synthesis method. The as-prepared nanoparticles were characterized using various measurements such as XRD, SEM with EDS, HRTEM, Raman spectroscopy, optical, PL, XPS and FT-IR techniques. The crystal structure and average particle sizes of the prepared nanoparticles were confirmed from the XRD. The average crystalline particle sizes were decreased by increasing the vanadium dopant concentration. The presence of vanadium as V<SUP>4+</SUP> species in the host lattice was confirmed by X-ray photoelectron spectroscopy. The band gap energies were decreased by increasing dopant concentration. The 0.05mol% doped sample showed higher photocatalytic activity than undoped, V-1 and V-3 in decomposing rhodamine B (RhB) under UV light irradiation. The Raman and IR spectra confirm the fundamental vibration of SnO<SUB>2</SUB> host molecules.

Hydrothermal Synthesis of H2V3O8 Nanobelts from V2O5 Xerogels for Lithium Battery Applications

Sun-Il Mho,Ch.V. Reddy,Youna Kim,In-Hyeong Yeo,Su-Moon Park 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.6

Vanadium oxyhydroxide (H2V3O8) nanobelts were synthesized from V2O5 xerogels through a simple hydrothermal process in efforts to obtain nanomaterials for rechargeable Li batteries. Polymers with multidentate oxygen ligands, such as polyethylene glycol or polyethylene oxide, were shown to play a critical role in the formation of H2V3O8 nanobelts during the hydrothermal process. The specific capacity measured during the initial discharge process for the lithium battery with a cathode made of H2V3O8 nanobelts were 292 mAh/g, which stabilized at ca. 261 mAh/g corresponding to two equivalents of Li intercalation/deintercalation into H2V3O8. Lithium batteries made of a vanadium-oxyhydroxide cathode showed better cycle stability than those with a V2O5 cathode.

Synthesis of VO2 (B) nanorods for Li battery application

Ch.V. Subba Reddy,Edwin H. Walker Jr.,S.A. Wicker Sr.,Quinton L. Williams,Rajamohan R. Kalluru 한국물리학회 2009 Current Applied Physics Vol.9 No.6

Vanadium dioxide nanorods were synthesized through a hydrothermal reaction from V2O5 xerogel, poly (vinyl pyrrolidone) (PVP) and lithium perchlorate (LiClO4). The prepared samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical discharge–charge cycling in lithium battery. SEM images reveal the nanorods to have dimensions on the order of 1–3 ㎛ in length and 10–50 nm in diameter. The measured initial discharge capacity of the lithium battery with a cathode made of VO2 (B) nanorods was 152 mA h/g. Vanadium dioxide nanorods were synthesized through a hydrothermal reaction from V2O5 xerogel, poly (vinyl pyrrolidone) (PVP) and lithium perchlorate (LiClO4). The prepared samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical discharge–charge cycling in lithium battery. SEM images reveal the nanorods to have dimensions on the order of 1–3 ㎛ in length and 10–50 nm in diameter. The measured initial discharge capacity of the lithium battery with a cathode made of VO2 (B) nanorods was 152 mA h/g.

In situ fabrication of the Bi₂O₃–V₂O₅ hybrid embedded with graphitic carbon nitride nanosheets: Oxygen vacancies mediated enhanced visible-light–driven photocatalytic degradation of organic pollut

Vattikuti, S.V. Prabhakar,Police, Anil Kumar Reddy,Shim, Jaesool,Byon, Chan Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.447 No.-

<P><B>Abstract</B></P> <P>Novel mesoporous ternary hybrids comprising Bi<SUB>2</SUB>O<SUB>3</SUB>/V<SUB>2</SUB>O<SUB>5</SUB> photocatalysts anchored on graphitic carbon nitride (g-C<SUB>3</SUB>N<SUB>4</SUB>) nanosheets were synthesized via an in situ co-pyrolysis approach and characterized by a series of techniques, including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller analysis, thermogravimetric-differential thermal analysis, Fourier transform infrared spectroscopy, ultraviolet–visible spectrometry, photoluminescence and electron paramagnetic resonance (EPR). The hybrids were subsequently tested as photocatalysts for the degradation of the phenol red (PR) pollutant under visible light irradiation. The well-designed ternary hybrids showed pure and randomly distributed Bi<SUB>2</SUB>O<SUB>3</SUB>/V<SUB>2</SUB>O<SUB>5</SUB> (denoted as BiV) nanoparticles on monodispersed g-C<SUB>3</SUB>N<SUB>4</SUB> nanosheets. The as-prepared ternary Bi<SUB>2</SUB>O<SUB>3</SUB>/V<SUB>2</SUB>O<SUB>5</SUB>@g-C<SUB>3</SUB>N<SUB>4</SUB> (i.e., BiV@g-C<SUB>3</SUB>N<SUB>4</SUB>) hybrids demonstrated high specific surface areas with remarkable mesoporous characteristics. The photodegradation efficiencies of the ternary hybrids for PR were 1.2 and 1.8 times higher than those of binary BiV and pristine Bi<SUB>2</SUB>O<SUB>3</SUB>, respectively, at 50 min irradiation time under simulated solar light irradiation. At the end of the phototreatment, the amount of PR pollutant was reduced to 98.1% in 50 min by using the BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> nanocomposites under simulated solar light irradiation and more efficient for photocatalytic H<SUB>2</SUB> production. Based on an electrochemical analysis, we propose a photocatalytic degradation pathway for PR under visible light irradiation. In addition, the BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> nanocomposite photocatalysts exhibited both long-term stability and photocatalytic efficiency for the degradation of the PR dye. The excellent photoelectrochemical performance of the BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> photocatalysts can be ascribed to their highly dispersed V<SUB>2</SUB>O<SUB>5</SUB> and Bi<SUB>2</SUB>O<SUB>3</SUB> nanoparticles, mesoporous structure, and high specific surface area (83.75 m<SUP>2</SUP> g<SUP>−1</SUP>).</P> <P><B>Highlights</B></P> <P> <UL> <LI> BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> photocatalyst was successfully synthesized via co-pyrolysis. </LI> <LI> Synthetic procedure may open up an opportunity to tailor the morphologies of nanocomposites. </LI> <LI> Studied the oxygen vacancies enhanced photocatalytic activity of BiV@g-C<SUB>3</SUB>N<SUB>4.</SUB> </LI> <LI> Photodegradation and H<SUB>2</SUB> evolution mechanism of the BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> photocatalyst is elucidated and discussed. </LI> <LI> BiV@g-C<SUB>3</SUB>N<SUB>4</SUB> photocatalyst demonstrated 21.08 folds higher H<SUB>2</SUB> production rate than pure ones. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Clinical Impact of Patient’s Head Position in Supraclavicular Irradiation of the Whole Breast Radiotherapy

Anbumani Surega,G. Reddy Lohith,V Priyadarshini,P Sasikala,S. Bilimagga Ramesh 한국의학물리학회 2023 의학물리 Vol.34 No.1

Patients with breast cancer can be positioned with their head turned to the contra lateral side or with their head straight during the radiation therapy treatment set-up. In our hospital, patients with locally advanced breast cancer who were receiving radiation therapy have experienced swallowing difficulty after 2 weeks of irradiation. In this pilot study, the impact of head position on reducing dysphagia occurrence was dosimetrically evaluated. Patients were divided into two groups viz., HT (head turned to the contra lateral side of the breast) and HS (head straight) with 10 members in each. Treatment planning was performed, and the dosimetric parameters such as Dmin, Dmax, Dmean, V5, V10, V20, V30, V40, and V50 of both groups were extracted from the dose volume histogram (DVH) of esophagus. The target coverage in the supraclavicular fossa (SCF) region was analyzed using D95 and D98; moreover, the dose heterogeneity was assessed with D2 from the DVHs. The average values of the dose volume parameters were 27.6%, 58.6%, 35.4%, 19%, 13.8%, 14.1%, 11.8%, 8.4%, and 8.1% higher in the HT group compared with those in the HS group. Furthermore, for the SCF, the mean values of D98, D95, and D2 were 42.4, 47.5, and 54 Gy, respectively, in the HS group and 38.9, 45.35, and 55.5 Gy, respectively, in the HT group. This pilot study attempts to give a solution for the poor quality of life of patients after breast radiotherapy due to dysphagia. The findings confirm that the head position could play a significant role in alleviating esophageal toxicity without compromising tumor control.

Simple Preparation of V₂O₅ Nanostructures and Their Characterization

Subba Reddy, Ch. V.,Park, Kyung-Il,Mho, Sun-il,Yeo, In-Hyeong,Park, Su-Moon Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.10

Simple Preparation of V2O5 Nanostructures and Their Characterization

모선일,Ch. V. Subba Reddy,Kyung-Il Park,여인형,박수문 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.10

Analgesic and Anti-inflammatory Activity of Carissa carandasLinn fruits and Microstylis wallichii Lindl Tubers

Alok Sharma,G.D. Reddy,Atul Kaushik,K.Shanker,R.K. Tiwari,Alok Mukherjee,Ch.V. Rao 한국생약학회 2007 Natural Product Sciences Vol.13 No.1

ethanolic (50% v/v) extracts of Carissa carandas (fruits) (Apocynaceae) and Microstylis wallichii(tubers) (Orchidaceae) were examined for anti-inflamatory and analgesic activities in experimental animals.Carissa carandas and Microstylis wallichii (50 - 200 mg/kg) caused a dose dependent inhibition of swellingcaused by carrageenin significantly in cotton pellet induced granuloma in rats (P < 0.05 to P < 0.001). There was asignificant increase in the analgesy meter induced pain in rats. The extracts of Carissa carandas and Microstyliswallichii resulted in an inhibition of stretching episodes and percentage protection was 16.05 - 17.58%respectively in acetic acid induced writhing.KeywordsCarissa carandas, Microstylis wallichii, pain, inflamation