Atul Suresh Deshpande

Simultaneously, high energy and power density are extremely desirable attributes in supercapacitors. Carbon‐based supercapacitors deliver high power but cannot retain significant energy density at high charging rates. Herein, it is demonstrated that the prudent selection of okra as a carbon precursor, diligent processing, and use of water‐in‐salt electrolyte (WiSE) to expand the voltage window ensures both high energy and high‐power density. Okra is an ideal carbon precursor as it contains a significant amount of water and minerals. Their methodical removal during processing yields okra‐derived activated carbon (OAC), having an ultrahigh surface area of 2109 m ² g ⁻¹ with an effective combination of micro/meso/macropores. The electrochemical studies of OAC in a three‐electrode system using 6 m KOH as an electrolyte display an outstanding capacitance of 318 F g ⁻¹ at 1 A g ⁻¹ . Furthermore, the potential window is extended to 1.6 V using a WiSE (27 molal CH ₃ COOK). This leads to a remarkable increase in energy density to 44.44 Wh kg ⁻¹ with an extraordinary power density of 80,000 W kg ⁻¹ at 50 A g ⁻¹ in two‐electrode system. 100% capacitance retention is observed after 10,000 cycles at 10 A g ⁻¹ . This study highlights the importance of pore engineering for superior electrochemical performance.

The rapid spread of microorganisms such as bacteria, fungi, and viruses can be extremely detrimental and can lead to seasonal epidemics or even pandemic situations. In addition, these microorganisms may bring about fouling of food and essential materials resulting in substantial economic losses. Typically, the microorganisms get transmitted by their attachment and growth on various household and high contact surfaces such as doors, switches, currency. To prevent the rapid spread of microorganisms, it is essential to understand the interaction between various microbes and surfaces which result in their attachment and growth. Such understanding is crucial in the development of antimicrobial surfaces. Here, we have reviewed different approaches to make antimicrobial surfaces and correlated surface properties with antimicrobial activities. This review concentrates on physical and chemical modification of the surfaces to modulate wettability, surface topography, and surface charge to inhibit microbial adhesion, growth, and proliferation. Based on these aspects, antimicrobial surfaces are classified into patterned surfaces, functionalized surfaces, superwettable surfaces, and smart surfaces. We have critically discussed the important findings from systems of developing antimicrobial surfaces along with the limitations of the current research and the gap that needs to be bridged before these approaches are put into practice.

Carbon–SnO_x composites are obtained by impregnating acetylacetone‐treated, delignified wood fibers with tin precursor and successively carbonizing at 1000 °C in 95% argon and 5% oxygen. Scanning electron microscopy and nitrogen sorption studies (Brunauer–Emmett–Teller) show that acetylacetone treatment stabilizes the wood fiber structure during carbonization at 1000 °C and preserves the porous structural features. X‐ray diffraction, transmission electron microscopy, and X‐ray photoelectron spectroscopy studies show that the small amount of oxygen introduced in inert atmosphere passivates the surface of tin nanoparticles. The passivation process yields thermally and electrochemically stable SnO_x particles embedded in carbon matrix. The resultant carbon–SnO_x material with 16 wt% SnO_x shows excellent electrochemical performance of rate capability from 0.1 to 10 A g⁻¹ and cycling stability for 1000 cycles with Li‐ion storage capacity of 280 mAh g⁻¹ at a current density of 10 A g⁻¹. The remarkable electrochemical performance of wood‐derived carbon–SnO_x composite is attributed to the reproduction of structural featured wood fibers to nanoscale in carbon–SnO_x composite and controlled passivation of tin nanoparticles to yield SnO_x nanoparticles.

Fully crystalline single phase multi-component fluorite oxide (Gd_0.2La_0.2Y_0.2Hf_0.2Zr_0.2O₂ and Gd_0.2La_0.2Ce_0.2Hf_0.2Zr_0.2O₂) nanoparticle sols were synthesized at low temperature (≤80 °C) by co-precipitation followed by peptization in acidic medium.