Bhaskar R. Sathe

Rhodium nanoparticle–carbon nanosphere hybrid material as an electrochemical hydrogen sensor

The highly monodispersed decoration of Rh nanoparticles (∼2.5 nm) on acid-functionalized carbon nanospheres (CNSs) has been demonstrated using a facile wet-chemical method. The electrochemical studies of the resulting Rh–CNS hybrid material displayed excellent H2 sensing properties.

High aspect ratio rhodium nanostructures for tunable electrocatalytic performance

Rh nanoneedles and nanorods have been generated with the help of functional molecules like hexamethylene tetraamine and tridecylamine (1:2 in mM scale) as effective capping agents for electrocatalytic studies. A noteworthy negative shift of the onset potential towards the electrooxidation of formic acid compared to that of bulk Rh from cyclic voltammetry along with current densities from current-time transient suggests their potential application as an efficient electrocatalyst for fuel cell.

Pd nanoparticles: an efficient catalyst for the solvent-free synthesis of 2,3-disubstituted-4-thiazolidinones

Palladium nanoparticles (Pd NPs: ~5-nm diameter) catalysed an efficient, solvent-free protocol for the cyclocondensation reaction of the aldehydes, anilines and mercaptoacetic acid has been developed. This method offers a rapid, relatively economical and ecofriendly protocol for the synthesis of 2,3-disubstituted-4-thiazolidinones for the first time. Moreover, the catalyst can also be easily recovered and recycled with no loss of catalytic activity.Graphical Abstract

Capping induced morphology evolution of Rh nanostructures and their electrocatalytic studies

A simple and versatile route based on a galvanic displacement approach for the shape-selective evolution of Rh nanostructures followed by their in situ integration assembly on a large scale has been designed and successfully developed by using polyvinylpyrrolidone (PVP) as a shape inducing agent. Comparative studies on the electrocatalytic activity of these morphologies were conducted towards many fuel cell reactions as demonstrated by HCHO oxidation.

Binder free 2D aligned efficient MnO2 micro flowers as stable electrodes for symmetric supercapacitor applications

Herein, δ-MnO2 micro-flower thin films are grown directly onto a stainless steel mesh via a simple rotational chemical bath deposition technique. Moreover, the influence of the concentration of precursor ratio of MnSO4 : KMnO4 is investigated and the obtained samples are designated as M1 (KMnO4 : MnSO4 = 3 : 1), M2 (KMnO4 : MnSO4 = 3 : 2) and M3 (KMnO4 : MnSO4 = 3 : 3). The concentration of MnSO4 as a starting material has a significant influence on the reaction kinetics, which subsequently alters the morphology and also the electrochemical performance. Among these three electrodes, the M1 electrode exhibits a high specific capacitance of 376 F g−1 at a current density of 5 mA cm−2 and a high specific energy of 52 W h kg−1, which is higher than M2 (specific capacitance 312 F g−1 and specific energy 43 W h kg−1) and M3 (specific capacitance 283 F g−1 and specific energy 39 W h kg−1) electrodes. Due to the interesting performance of the M1 based electrode, the symmetric device is fabricated using two electrodes M1 (3 : 1) and represented as SSM/M1//M1/SSM. The device provides a maximum specific capacitance of 87 F g−1 and specific energy density of 32 W h kg−1 at a current density of 5 mA cm−2. In addition, the symmetric device of the M1 electrode also exhibits good cycle stability showing 138% capacitance retention up to 2500 cycles. The enhanced electrochemical performance could be attributed to the direct growth of micro-flowers of MnO2 on a stainless steel mesh, which provides more pathways for easy diffusion of electrolyte ions into the electrode. This study provides new insight and pathways for the development of low-cost and high-performance energy storage devices.

Ultrasensitive and bifunctional ZnO nanoplates for an oxidative electrochemical and chemical sensor of NO2: implications towards environmental monitoring of the nitrite reaction

Herein, we focused on the one pot synthesis of ZnO nanoplates (NP edge thickness of ∼100 nm) using a chemical emulsion approach for chemical (direct) and electrochemical (indirect) determination of NO2. The structural and morphological elucidation of the as-synthesized ZnO NPs was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), thermogravimetric analysis (TGA) and BET-surface area measurements. The XRD studies of the as-synthesised NPs reveal that ZnO NPs have a Wurtzite type crystal structure with a crystallite size of ∼100 nm. Such ZnO NPs were found to be highly sensitive to NO2 gas at an operating temperature of 200 °C. Electrocatalytic abilities of these ZnO NPs towards NO2/NO2− were verified through cyclic voltammetry (CV) and linear sweep voltammetry (LSV) using aqueous 1 mM NO2− (nitrite) in phosphate buffer (pH 7) solution. The results revealed enhanced activity at an onset potential of 0.60 V vs. RCE, achieved at a current density of 0.14 mA cm−2. These ZnO NPs show selective NO2 detection in the presence of other reactive species including CO, SO2, CH3OH and Cl2. These obtained results show that this chemical route is a low cost and promising method for ZnO NPs synthesis and recommend further exploration into its applicability towards tunable electrochemical as well as solid state gas sensing of other toxic gases.

Temperature dependent fabrication of cost-effective and nontoxic Cu2ZnSnS4 (CZTS) thin films for solar cell

In the present work, Cu2ZnSnS4 (CZTS) thin films have been fabricated onto the glass substrate by simple and economic chemical bath deposition technique1, and the effect of deposition temperature is reported. The deposition temperatures used were 50°C and 60°C for a deposition time of 60 min, which are significantly lower than earlier reports. These CZTS thin films were characterized for optical, electrical, morphological and elemental properties using, UV-Vis spectrophotometer, I-V system for photosensitivity, two probe resistivity system for resistivity, scanning electron microscopy, energy dispersive spectroscopy and Raman spectroscopy.

Enhanced electrocatalytic hydrogen generation from water via cobalt-doped Cu2ZnSnS4 nanoparticles

Herein, we adopted a novel noble metal-free Co-doped CZTS-based electrocatalyst for the hydrogen evolution reaction (HER), which was fabricated using a facile, effective, and scalable strategy by employing a sonochemical method. The optimized Co-doped CZTS electrocatalyst shows a superior HER performance with a small overpotential of 200 and 298 mV at 2 and 10 mA−1, respectively, and Tafel slope of 73 mV dec−1, and also exhibits excellent stability up to 700 cycles with negligible loss of the cathodic current. The ease of synthesis and high activity of the Co-doped CZTS-based cost-effective catalytic system appear to be promising for HER catalysis.

Biomass-Mediated Synthesis of Cu-Doped TiO2 Nanoparticles for Improved-Performance Lithium-Ion Batteries

Pure TiO2 and Cu-doped TiO2 nanoparticles are synthesized by the biomediated green approach using the Bengal gram bean extract. The extract containing biomolecules acts as capping agent, which helps to control the size of nanoparticles and inhibit the agglomeration of particles. Copper is doped in TiO2 to enhance the electronic conductivity of TiO2 and its electrochemical performance. The Cu-doped TiO2 nanoparticle-based anode shows high specific capacitance, good cycling stability, and rate capability performance for its envisaged application in lithium-ion battery. Among pure TiO2, 3% Cu-doped TiO2, and 7% Cu-doped TiO2 anode, the latter shows the highest capacity of 250 mAh g–1 (97.6% capacity retention) after 100 cycles and more than 99% of coulombic efficiency at 0.5 A g–1 current density. The improved electrochemical performance in the 7% Cu-doped TiO2 is attributed to the synergetic effect between copper and titania. The results reveal that Cu-doped TiO2 nanoparticles might be contributing to the enhanced electronic conductivity, providing an efficient pathway for fast electron transfer.