Anitha Devadoss | Heriot-Watt University (original) (raw)

Papers by Anitha Devadoss

Environmental Chemistry for a Sustainable World, 2019

Developing toxic-free material synthesis route shows great demand for sustainable environment. In... more Developing toxic-free material synthesis route shows great demand for sustainable environment. In particular, green-synthesized catalyst material perceived great attention in environmental- and biomedical-based applications. Mostly conventional chemical synthesis route contains particle stabilizer agent for obtaining low-dimensional nanoparticle or avoiding particle aggregation. Unfortunately, these chemicals are highly toxic to the environment. In this context, plant extract, biomass, and algae can be utilized as green bio-surfactant without polluting the environment. This chapter explores the recent development of green synthesis routes for photocatalyst synthesis using plant extract, and their capability in organic pollutant removal from the water will be discussed in detail.

Applied Surface Science, 2019

Pitchaimuthu, S. (2019). Utilization of waste tea leaves as bio-surfactant in CdS quantum dots sy... more Pitchaimuthu, S. (2019). Utilization of waste tea leaves as bio-surfactant in CdS quantum dots synthesis and their cytotoxicity effect in breast cancer cells.

2D Nanoscale Heterostructured Materials

Abstract This chapter provides a generalized overall picture about fundamental electrochemical pr... more Abstract This chapter provides a generalized overall picture about fundamental electrochemical properties of transition metal dichalcogenides (TMDs) and their recent applications in wide range of energy technologies (battery, supercapacitor, and water splitting). The high surface area, large number of active sites, and remarkable chemical stability offer TMDs with vast opportunities for utilizing as a promising electrocatalysts. However, inadequate electrical conductivity and other deficiencies foster considerable research efforts for further modification. The TMDs showed enhanced electrocatalytic performance through (1) site doping/modification, (2) phase modulation, (3) control of growth morphology, and (4) heterostructure formation. This chapter summarizes the recent demonstration of these methodologies in TMDs towards designing the efficient and benchmarking electrocatalysts. Furthermore, the underlying mechanism of device functionality, materials challenges, and perspectives of TMD based electrocatalysts are also discussed in this chapter.

Journal of the Electrochemical Society, 2014

Sensors and Actuators B: Chemical, 2015

Abstract We demonstrate that carbon nitride nanotube (CNNT) hybrids modified with CoPt nanopartic... more Abstract We demonstrate that carbon nitride nanotube (CNNT) hybrids modified with CoPt nanoparticles (CoPt NPs) oxidize reduced nicotinamide adenine dinucleotide (NADH) to a greater extent than carbon nanotubes (CNTs) or CNNTs alone due to synergistic interactions between the CNNTs and the CoPt NPs through the improved internal network. Heterogeneous nitrogen atoms in the sp2 carbon network provide strong binding sites for in-situ synthesis of CoPt NPs of homogeneous size. The increase in heterogeneous charge transfer on the CoPt-CNNT hybrid electrode enhanced the electrochemical oxidation of NADH at a low applied potential compared to those for pristine CNTs or CNNTs. Our results suggest that CoPt-CNNT hybrids are highly stable and ideal for use in electrochemical sensing.

CrystEngComm, 2015

The pocket-sized nebulizer equipped jet-spray coating of a monoclinic CuO crystallite surface sho... more The pocket-sized nebulizer equipped jet-spray coating of a monoclinic CuO crystallite surface showed excellent superhydrophobic self-cleaning properties owing to its compact crystallite texture and high surface roughness.

Materials Science in Semiconductor Processing, 2015

Abstract We report the synthesis of bismuth vanadate (BiVO4) nanostructure by atoxic-free, inexpe... more Abstract We report the synthesis of bismuth vanadate (BiVO4) nanostructure by atoxic-free, inexpensive co-precipitation method. The BiVO4 nanostructures were derived from bismuth nitrate and ammonia metavanadate as starting precursors and sodium hydroxide (NaOH) were used as stabilizers for tuning the morphology (nanorod, nanospheriod and nanoparticulate). The influence of post-calcination treatment (450, 550 and 650 °C) on structural, optical and photocatalytic properties of BiVO4 was studied. The post-calcination treatment strongly induces the crystallization process and produce monoclinic BiVO4 structure with predominant (112) crystallite phases. The absorbance of BiVO4 shows broad coverage of visible light wavelength region up to 550 nm, which is appreciable for solar light driven photocatalysis. Among the different calcinated samples, anisotropy rod-shape BiVO4 (calcinated at 450 °C) shows high optical absorbance than other treated (550 and 650 °C) samples. The monotonic shift in characteristic Raman vibration mode at 824 cm−1 with increasing calcination temperature indicates that the V–O bond length is affected by Bi3+ diffusivity. The PL spectra of these samples explore the intrinsic defects present in BiVO4, and found to be high in high temperature calcinated samples. The photocatalytic property of resultant BiVO4 samples was evaluated in oxygen generation with Ag+ donors. As a result of reduced defects and high optical absorbance, the BiVO4 calcinated at 450 °C showed high photocatalytic oxygen yield (1.02 mmol) compared with high temperature calcinated samples (0.48 mmol).The appreciable quantity of solar fuel O2 generation from the low-cost co-precipitation method can be widely implemented in other visible light metal oxide nanostructures.

Chemical communications (Cambridge, England), Jan 11, 2015

The solar-to-hydrogen generation from the TiO2-CdS-ZnS-MoS2 (TCZM) heterointerface was demonstrat... more The solar-to-hydrogen generation from the TiO2-CdS-ZnS-MoS2 (TCZM) heterointerface was demonstrated. We found that a Pt-free CdS quantum dot-sensitized TiO2 mesoporous electrode with a metallic-type 1T MoS2 co-catalyst resulted in 0.11 ml cm(-2) h(-1) H2 fuel generation in unassisted potential mode, which was strikingly improved to 1.47 ml cm(-2) h(-1) under 1 V applied potential.

Physical chemistry chemical physics : PCCP, Jan 21, 2014

We report simultaneous photoelectrocatalytic (PEC) glucose sensing and biohydrogen generation for... more We report simultaneous photoelectrocatalytic (PEC) glucose sensing and biohydrogen generation for the first time from the direct PEC oxidation of glucose at multifunctional and robust Cu2O-TiO2 photocatalysts. Striking improvement of 30% in overall H2 gas evolution (∼122 μmol h(-1) cm(-2)) by photoholes assisted glucose oxidation opens a new platform in solar-driven PEC biohydrogen generation.

ECS Transactions, 2010

Metallopolymer-gold nanocomposites were prepared by mixing 4-(dimethylamino) pyridine protected g... more Metallopolymer-gold nanocomposites were prepared by mixing 4-(dimethylamino) pyridine protected gold nanoparticles (diameter approximately 5{plus minus}0.5 nm) and [Ru(bpy)2PVP10](ClO4)2, at different mole ratios where bpy is 2,2'-bipyridyl and PVP is poly(4-vinylpyridine). The photoluminescence emission intensity of the metallopolymer is quenched approximately 72% at AuNP:Ru molar ratio of 12.5x10-2. The electrochemical and the electrochemiluminescence (ECL) properties of thin layers of the nanocomposites are reported. Significantly, despite the ability of the metal nanoparticles to quench the ruthenium based emission in solution, the electrochemiluminescence of the optimized nanocomposite films (mole ratio 6.24x10-2) is approximately 3.5 times greater than that of the parent metallopolymer. This enhancement arises from the increased rate of charge transport through the thin films that leads to a greater number of excited states per unit time while minimizing the quenching effe...

The Journal of Physical Chemistry C, 2013

Hybrid nanofibers of polyaniline/polyoxometalate are synthesized via a facile interfacial polymer... more Hybrid nanofibers of polyaniline/polyoxometalate are synthesized via a facile interfacial polymerization method for the first time, and evaluated as a cathode material for lithium ion batteries. The hybrid nanofibers with 100 nm diameter consisted of phosphomolybdic acid polyanion, [PMo 12 O 40 ] 3− , and polyaniline matrix. Their 1D geometry improves the utilization of electrode materials and accommodates the volume change during cycling, which enables the significant improvement in lithium storage capacity and capacity retentions. The phosphomolybdic acid polyanions not only exhibit a large theoretical capacity of about 270 mAh g −1 , but also reduce the charge transfer resistance of electrode leading to the enhanced reversible capacity and rate capability. The polyaniline/polyoxometalate nanofibers delivered a remarkably improved electrochemical performance in terms of lithium storage capacity (183.4 mAh g −1 at 0.1C rate), cycling stability (80.7% capacity retention after 50 cycles), and rate capability (94.2 mAh g −1 at 2C rate) compared to polyaniline nanofibers and bulk polyaniline/polyoxometalate hybrid.

Journal of Physics D: Applied Physics, 2007

... 9 mol% Mg in ZnO films and attributed the decrease in the c-lattice constant to the rocksalt ... more ... 9 mol% Mg in ZnO films and attributed the decrease in the c-lattice constant to the rocksalt lattice of MgO. Muthukumar et al [62] showed the importance of a buffer ZnO layer for the deposition of such epitaxial films with a wurtzite structure. ...

Electrochimica Acta, 2013

Electrochemistry Communications, 2012

Electrochemistry Communications, 2012

Electrochemistry Communications, 2011

Analytical Chemistry, 2011

ACS Nano, 2012

Titanium dioxide (TiO(2)) is one of the most promising anode materials for lithium ion batteries ... more Titanium dioxide (TiO(2)) is one of the most promising anode materials for lithium ion batteries due to low cost and structural stability during Li insertion/extraction. However, its poor rate capability limits its practical use. Although various approaches have been explored to overcome this problem, previous reports have mainly focused on the enhancement of both the electronic conductivity and the kinetic associated with lithium in the composite film of active material/conducting agent/binder. Here, we systematically explore the effect of the contact resistance between a current collector and a composite film of active material/conducting agent/binder on the rate capability of a TiO(2)-based electrode. The vertically aligned TiO(2) nanotubes arrays, directly grown on the current collector, with sealed cap and unsealed cap, and conventional randomly oriented TiO(2) nanotubes electrodes were prepared for this study. The vertically aligned TiO(2) nanotubes array electrode with unsealed cap showed superior performance with six times higher capacity at 10 C rate compared to conventional randomly oriented TiO(2) nanotubes electrode with 10 wt % conducting agent. On the basis of the detailed experimental results and associated theoretical analysis, we demonstrate that the reduction of the contact resistance between electrode and current collector plays an important role in improving the electronic conductivity of the overall electrode system.

ACS Applied Materials & Interfaces, 2014

We report the fabrication of graphene-WO3-Au hybrid membranes and evaluate their photocatalytic a... more We report the fabrication of graphene-WO3-Au hybrid membranes and evaluate their photocatalytic activity towards glucose oxidase mediated enzymatic glucose oxidation. The dual-functionality of gold nanoparticles in the reinforcement of visible light activity of graphene-WO3 membranes and improving the catalytic activity of immobilized enzymes for unique photoelectrochemical sensing application is demonstrated. This work provides new insights into the fabrication of light-sensitive hybrid materials and facilitates their application in future.

Environmental Chemistry for a Sustainable World, 2019

Developing toxic-free material synthesis route shows great demand for sustainable environment. In... more Developing toxic-free material synthesis route shows great demand for sustainable environment. In particular, green-synthesized catalyst material perceived great attention in environmental- and biomedical-based applications. Mostly conventional chemical synthesis route contains particle stabilizer agent for obtaining low-dimensional nanoparticle or avoiding particle aggregation. Unfortunately, these chemicals are highly toxic to the environment. In this context, plant extract, biomass, and algae can be utilized as green bio-surfactant without polluting the environment. This chapter explores the recent development of green synthesis routes for photocatalyst synthesis using plant extract, and their capability in organic pollutant removal from the water will be discussed in detail.

Applied Surface Science, 2019

Pitchaimuthu, S. (2019). Utilization of waste tea leaves as bio-surfactant in CdS quantum dots sy... more Pitchaimuthu, S. (2019). Utilization of waste tea leaves as bio-surfactant in CdS quantum dots synthesis and their cytotoxicity effect in breast cancer cells.

2D Nanoscale Heterostructured Materials

Abstract This chapter provides a generalized overall picture about fundamental electrochemical pr... more Abstract This chapter provides a generalized overall picture about fundamental electrochemical properties of transition metal dichalcogenides (TMDs) and their recent applications in wide range of energy technologies (battery, supercapacitor, and water splitting). The high surface area, large number of active sites, and remarkable chemical stability offer TMDs with vast opportunities for utilizing as a promising electrocatalysts. However, inadequate electrical conductivity and other deficiencies foster considerable research efforts for further modification. The TMDs showed enhanced electrocatalytic performance through (1) site doping/modification, (2) phase modulation, (3) control of growth morphology, and (4) heterostructure formation. This chapter summarizes the recent demonstration of these methodologies in TMDs towards designing the efficient and benchmarking electrocatalysts. Furthermore, the underlying mechanism of device functionality, materials challenges, and perspectives of TMD based electrocatalysts are also discussed in this chapter.

Journal of the Electrochemical Society, 2014

Sensors and Actuators B: Chemical, 2015

Abstract We demonstrate that carbon nitride nanotube (CNNT) hybrids modified with CoPt nanopartic... more Abstract We demonstrate that carbon nitride nanotube (CNNT) hybrids modified with CoPt nanoparticles (CoPt NPs) oxidize reduced nicotinamide adenine dinucleotide (NADH) to a greater extent than carbon nanotubes (CNTs) or CNNTs alone due to synergistic interactions between the CNNTs and the CoPt NPs through the improved internal network. Heterogeneous nitrogen atoms in the sp2 carbon network provide strong binding sites for in-situ synthesis of CoPt NPs of homogeneous size. The increase in heterogeneous charge transfer on the CoPt-CNNT hybrid electrode enhanced the electrochemical oxidation of NADH at a low applied potential compared to those for pristine CNTs or CNNTs. Our results suggest that CoPt-CNNT hybrids are highly stable and ideal for use in electrochemical sensing.

CrystEngComm, 2015

The pocket-sized nebulizer equipped jet-spray coating of a monoclinic CuO crystallite surface sho... more The pocket-sized nebulizer equipped jet-spray coating of a monoclinic CuO crystallite surface showed excellent superhydrophobic self-cleaning properties owing to its compact crystallite texture and high surface roughness.

Materials Science in Semiconductor Processing, 2015

Abstract We report the synthesis of bismuth vanadate (BiVO4) nanostructure by atoxic-free, inexpe... more Abstract We report the synthesis of bismuth vanadate (BiVO4) nanostructure by atoxic-free, inexpensive co-precipitation method. The BiVO4 nanostructures were derived from bismuth nitrate and ammonia metavanadate as starting precursors and sodium hydroxide (NaOH) were used as stabilizers for tuning the morphology (nanorod, nanospheriod and nanoparticulate). The influence of post-calcination treatment (450, 550 and 650 °C) on structural, optical and photocatalytic properties of BiVO4 was studied. The post-calcination treatment strongly induces the crystallization process and produce monoclinic BiVO4 structure with predominant (112) crystallite phases. The absorbance of BiVO4 shows broad coverage of visible light wavelength region up to 550 nm, which is appreciable for solar light driven photocatalysis. Among the different calcinated samples, anisotropy rod-shape BiVO4 (calcinated at 450 °C) shows high optical absorbance than other treated (550 and 650 °C) samples. The monotonic shift in characteristic Raman vibration mode at 824 cm−1 with increasing calcination temperature indicates that the V–O bond length is affected by Bi3+ diffusivity. The PL spectra of these samples explore the intrinsic defects present in BiVO4, and found to be high in high temperature calcinated samples. The photocatalytic property of resultant BiVO4 samples was evaluated in oxygen generation with Ag+ donors. As a result of reduced defects and high optical absorbance, the BiVO4 calcinated at 450 °C showed high photocatalytic oxygen yield (1.02 mmol) compared with high temperature calcinated samples (0.48 mmol).The appreciable quantity of solar fuel O2 generation from the low-cost co-precipitation method can be widely implemented in other visible light metal oxide nanostructures.

Chemical communications (Cambridge, England), Jan 11, 2015

The solar-to-hydrogen generation from the TiO2-CdS-ZnS-MoS2 (TCZM) heterointerface was demonstrat... more The solar-to-hydrogen generation from the TiO2-CdS-ZnS-MoS2 (TCZM) heterointerface was demonstrated. We found that a Pt-free CdS quantum dot-sensitized TiO2 mesoporous electrode with a metallic-type 1T MoS2 co-catalyst resulted in 0.11 ml cm(-2) h(-1) H2 fuel generation in unassisted potential mode, which was strikingly improved to 1.47 ml cm(-2) h(-1) under 1 V applied potential.

Physical chemistry chemical physics : PCCP, Jan 21, 2014

We report simultaneous photoelectrocatalytic (PEC) glucose sensing and biohydrogen generation for... more We report simultaneous photoelectrocatalytic (PEC) glucose sensing and biohydrogen generation for the first time from the direct PEC oxidation of glucose at multifunctional and robust Cu2O-TiO2 photocatalysts. Striking improvement of 30% in overall H2 gas evolution (∼122 μmol h(-1) cm(-2)) by photoholes assisted glucose oxidation opens a new platform in solar-driven PEC biohydrogen generation.

ECS Transactions, 2010

Metallopolymer-gold nanocomposites were prepared by mixing 4-(dimethylamino) pyridine protected g... more Metallopolymer-gold nanocomposites were prepared by mixing 4-(dimethylamino) pyridine protected gold nanoparticles (diameter approximately 5{plus minus}0.5 nm) and [Ru(bpy)2PVP10](ClO4)2, at different mole ratios where bpy is 2,2'-bipyridyl and PVP is poly(4-vinylpyridine). The photoluminescence emission intensity of the metallopolymer is quenched approximately 72% at AuNP:Ru molar ratio of 12.5x10-2. The electrochemical and the electrochemiluminescence (ECL) properties of thin layers of the nanocomposites are reported. Significantly, despite the ability of the metal nanoparticles to quench the ruthenium based emission in solution, the electrochemiluminescence of the optimized nanocomposite films (mole ratio 6.24x10-2) is approximately 3.5 times greater than that of the parent metallopolymer. This enhancement arises from the increased rate of charge transport through the thin films that leads to a greater number of excited states per unit time while minimizing the quenching effe...

The Journal of Physical Chemistry C, 2013

Hybrid nanofibers of polyaniline/polyoxometalate are synthesized via a facile interfacial polymer... more Hybrid nanofibers of polyaniline/polyoxometalate are synthesized via a facile interfacial polymerization method for the first time, and evaluated as a cathode material for lithium ion batteries. The hybrid nanofibers with 100 nm diameter consisted of phosphomolybdic acid polyanion, [PMo 12 O 40 ] 3− , and polyaniline matrix. Their 1D geometry improves the utilization of electrode materials and accommodates the volume change during cycling, which enables the significant improvement in lithium storage capacity and capacity retentions. The phosphomolybdic acid polyanions not only exhibit a large theoretical capacity of about 270 mAh g −1 , but also reduce the charge transfer resistance of electrode leading to the enhanced reversible capacity and rate capability. The polyaniline/polyoxometalate nanofibers delivered a remarkably improved electrochemical performance in terms of lithium storage capacity (183.4 mAh g −1 at 0.1C rate), cycling stability (80.7% capacity retention after 50 cycles), and rate capability (94.2 mAh g −1 at 2C rate) compared to polyaniline nanofibers and bulk polyaniline/polyoxometalate hybrid.

Journal of Physics D: Applied Physics, 2007

... 9 mol% Mg in ZnO films and attributed the decrease in the c-lattice constant to the rocksalt ... more ... 9 mol% Mg in ZnO films and attributed the decrease in the c-lattice constant to the rocksalt lattice of MgO. Muthukumar et al [62] showed the importance of a buffer ZnO layer for the deposition of such epitaxial films with a wurtzite structure. ...

Electrochimica Acta, 2013

Electrochemistry Communications, 2012

Electrochemistry Communications, 2012

Electrochemistry Communications, 2011

Analytical Chemistry, 2011

ACS Nano, 2012

Titanium dioxide (TiO(2)) is one of the most promising anode materials for lithium ion batteries ... more Titanium dioxide (TiO(2)) is one of the most promising anode materials for lithium ion batteries due to low cost and structural stability during Li insertion/extraction. However, its poor rate capability limits its practical use. Although various approaches have been explored to overcome this problem, previous reports have mainly focused on the enhancement of both the electronic conductivity and the kinetic associated with lithium in the composite film of active material/conducting agent/binder. Here, we systematically explore the effect of the contact resistance between a current collector and a composite film of active material/conducting agent/binder on the rate capability of a TiO(2)-based electrode. The vertically aligned TiO(2) nanotubes arrays, directly grown on the current collector, with sealed cap and unsealed cap, and conventional randomly oriented TiO(2) nanotubes electrodes were prepared for this study. The vertically aligned TiO(2) nanotubes array electrode with unsealed cap showed superior performance with six times higher capacity at 10 C rate compared to conventional randomly oriented TiO(2) nanotubes electrode with 10 wt % conducting agent. On the basis of the detailed experimental results and associated theoretical analysis, we demonstrate that the reduction of the contact resistance between electrode and current collector plays an important role in improving the electronic conductivity of the overall electrode system.

ACS Applied Materials & Interfaces, 2014

We report the fabrication of graphene-WO3-Au hybrid membranes and evaluate their photocatalytic a... more We report the fabrication of graphene-WO3-Au hybrid membranes and evaluate their photocatalytic activity towards glucose oxidase mediated enzymatic glucose oxidation. The dual-functionality of gold nanoparticles in the reinforcement of visible light activity of graphene-WO3 membranes and improving the catalytic activity of immobilized enzymes for unique photoelectrochemical sensing application is demonstrated. This work provides new insights into the fabrication of light-sensitive hybrid materials and facilitates their application in future.