Publications

Electrosynthesis of hydrogen peroxide (H2O2), as a sustainable alternative to the anthraquinone oxidation method, provides the feasibility of directly generating H2O2. Here, we report Cu-doped TiO2 as an efficient electrocatalyst which exhibits the excellent two-electron oxygen reduction reaction (2e− ORR) performance with respect to the pristine TiO2. The Cu doping results in the distortion of TiO2 lattice and further forms a large number of oxygen vacancies and Ti3+. Such Cu-doped TiO2 exhibits a positive onset potential about 0.79 V and high H2O2 selectivity about 91.2%. Moreover, it also shows a larger H2O2 yield and good stability. Density functional theory (DFT) calculations reveal that Cu dopant not only improves the electrical conductivity of pristine TiO2 but reduces the *OOH adsorption energy of active sites, which is beneficial to promote subsequently 2e− ORR process.

A novel phenothiazine derivative conjugated with vinylcyclohexenyl-malononitrile (PTZ-CDN) was synthesized through the Knoevenagel reaction of 10-octyl-10H-phenothiazine-3,7-dicarbaldehyde with 2-(3,5,5-trimethylcyclohex-2-en-1-ylidene)-malononitrile and fully characterized. The UV-vis absorption spectra of PTZ-CDN in different solvents showed a λ_max band at 497-531 nm with a high molar extinction coefficient attributed to intramolecular charge transfer (ICT) with the characteristics of a π-π* transition. Increasing the solvent polarity resulted in a bathochromic shift of λ_max . The PTZ-CDN fluorescence emission spectra were more sensitive to increasing the solvent polarity than the absorption spectra; they displayed a blue shift of λ_em by 85 nm. To understand the behaviour of the PTZ-CDN derivative, Stokes' shift ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Δ</mml:mi> <mml:mover><mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo></mml:mover> <mml:mo>)</mml:mo></mml:math> with respect to the solvent polarity, Lippert-Mataga and linear solvation-energy relationship (LSER) models were applied in which the LSER showed better regression than the Lippert-Mataga plots (r² = 0.9627). Finally, the TD-density functional theory (DFT) electronic transition spectra in dioxane and dimethyl formamide (DMF) were calculated. The DFT data showed that λ_max resulted from the support of the highest occupied molecular orbital to the lowest unoccupied molecular orbital transition with 74% and 99% in dioxane and DMF, respectively.

Non-fullerene (NF)-based compounds have attracted much attention as compared to fullerene-based materials because of their promising optoelectronic properties, lower synthetic cost and greater stability. Usually, the end-capped groups have a promising impact in magnifying the nonlinear optical (NLO) characteristics in the non-fullerene molecules. Based on this, a series of new NLO active non-fullerene molecules (NFAD2-NFAD6) have been established. The non-fullerene molecules (NFAD2-NFAD6) were designed by end-capped modification in acceptor moieties of the reference (NFAR1), while donor and π-bridge moieties were kept the same in the entire series. Quantum chemistry-based calculations at the M06/6-311G(d,p) level were done to determine the NLO characteristics and for other supportive analyses. The acceptor and donor moieties were utilized at the opposite terminals of NFAD2-NFAD6, which proved to be an effective approach in tuning the FMO band gap. Overall the results of natural bond orbital (NBO), density of state (DOS) and transition density matrices (TDMs) analyses supported the NLO properties of the designed compounds. Among all the studied compounds, NFAD4 was proven to be the most suitable candidate due to its promising NLO properties, well supported by a lower bandgap of 1.519 eV and a maximum absorption wavelength of 999.550 nm. Therefore, NFAD4 was reported with greater amplitude of dipole polarizability (10.429 e.s.u), average polarizability (2.953 × 10^-22 e.s.u), first hyperpolarizability (13.16 × 10^-27 e.s.u.) and second hyperpolarizability (2.150 × 10^-31 e.s.u.) than other derivatives and NFAR1. Subsequently, the present study depicted the significance of utilizing different non-fullerene (NF)-based acceptor moieties to achieve the promising NLO material. This computational study may lead towards new plausible pathways for researchers to design potent NLO substances for impending hi-tech applications.

A series of scarce N-alkyl-2,5-unsubstituted/monosubstituted fulleropyrrolidines were synthesized in moderate to excellent yields by the simple one-step thermal reaction of [60]fullerene with primary/secondary amines in the presence of paraformaldehyde without the addition of valuable metal salts. Intriguingly, the reaction with primary amines unexpectedly afforded N-alkyl-2,5-unsubstituted fulleropyrrolidines instead of the anticipated 2,5-monosubstituted fulleropyrrolidines. A plausible reaction pathway is proposed to elucidate the above-mentioned reaction process based on the experimental results.

Oxaprozin is a common anti-inflammatory drug in the clinic. Oral medication of oxaprozin potentially induces the GI perforation, which is caused by the local irritation of its carboxylic acid group. Paeonol is an active ingredient of peony, and has anti-inflammatory and anti-oxidant effects. So oxaprozin-paeonol ester (OPE) was designed to avoid the GI complications and enhence corresponding anti-inflammatory. The topical anti-inflammatory effects of OPE was evaluated in a 12-O-tetradecanoylphorbol-13-acetate (TPA) induced mouse ear edema model. The results showed that topical treatment of OPE could effectively improve the TPA-induced ear edema and its anti-inflammatory effect is 2 times higher than that of oxaprozin and 4 times than that of paeonol. Moreover, OPE treatment could effectively mitigate the expression of IL-1, IL-6, and TNF-, and its effect is better than that of oxaprozin or paeonol. Furthor study demonstrated that topical treatment of OPE could obviously down-regulate the activation of factor kappa-B (NF-B) by blocking IB kinase (IKK) activities. Accordingly, OPE might be used as a promising anti-inflammatory agent for inflammation-associated skin diseases.

Ceria nanoparticles with rhodamine B (RhB-CeNPs) are a new class of biocompatible nanomaterial with antioxidant activity and sensor capacity against oxidant species both in solution and in human cells.

The advancement of cost-effective and selective electrocatalyst towards CO2 to CO conversion is crucial for renewable energy conversion and storage, thus to achieve carbon-neutral cycle in a sustainable manner. In this communication, we report that Cu2Sb decorated Cu nanowire arrays on Cu foil act as a highly active and selective electrocatalyst for CO2 to CO conversion. In CO2-saturated 0.1 M KHCO3, it achieves a high Faraday efficiency (FE) of 86.5% for CO, at −0.90 V vs. reversible hydrogen electrode (RHE). The H2/CO ratio is tunable from 0.08:1 to 5.9:1 by adjusting the potential. It is worth noting that HCOO− product was totally suppressed on such catalyst, compared with Sb counterpart. The improving selectivity for CO could be attributed to the bimetallic effect and nanowire arrays structure.

In the present work, an attempt has been made to fabricate hybrid natural fiber composites, consisting of a poly-lactic-acid (PLA) matrix reinforced with jute and sisal fibers, using die molding process. The processing conditions of the hybrid composites, such as heating temperature, compression pressure, and final mold temperature, have been optimized in the response of the resulting tensile and flexural strength. The reinforced hybrid composites have been developed in accordance with the Taguchi L9-based design of experimentation, and statistical analysis has been performed to understand the significance of the selected input parameters. Furthermore, scanning electron microscopic (SEM) analysis of the fractured samples has been performed to observe the mechanisms of failure and adhesive characteristics. The statistical analysis highlighted that all input process parameters have significantly contributed to the resulting tensile and flexural strength at 95% confidence level.