Publications

In this letter, we report on the use of a cobalt phosphide nanowall array on conductive carbon cloth (CoP NA/CC) as an efficient catalyst electrode for methanol electro-oxidation under alkaline conditions. This CoP NA/CC achieves a current density of 96 mA cm(-2) toward 0.5 M methanol at 0.5 V (versus a saturated calomel electrode (SCE)) in 1 M KOH. Moreover, this electrode exhibits superior stability and 93% of the initial anodic current density can be retained after 1000 cyclic voltammetry cycles when re-measured in new electrolyte.

Different chitosan-titanium oxide (CS-TiO₂-x, with x = TiO₂ loadings of 1, 5, 10,15 and 20 wt%) nanocomposite fibers were prepared and kept separately in each salt solution of CuSO₄, CoNO₃, AgNO₃ and NiSO₄ to adsorb Cu²⁺, Co²⁺, Ag⁺, and Ni⁺ ions, respectively. The metal ions loaded onto CS-TiO₂ fibers were reduced to their respective zero-valent metal nanoparticles (ZV-MNPs) like Cu⁰, Co⁰, Ag⁰ and Ni⁰ by treating with NaBH₄. The CS-TiO₂ fibers templated with various ZV-MNPs were characterized and investigated for their catalytic efficiency. Among all prepared ZV-MNPs, Cu⁰ nanoparticles templated on CS-TiO₂-15 fibers exhibited high catalytic efficiency for the reduction of dyes (methyl orange (MO), congo red (CR), methylene blue (MB) and acridine orange (AO)) and nitrophenols (4-nitrohphenol (4-NP), 2-nitrophenol (2-NP), 3-nitrophenol (3-NP) and 2,6-dinitrophenol (2,6-DNP)). Besides the good catalytic activities of Cu/CS-TiO₂-15 fibers, it could be easily recovered by simply pulling the fiber from the reaction medium.

Biochar, as a cost-efficient adsorbent, is of major interest in the removal of heavy metals from wastewater. Herein, batch experiments were conducted to investigate the performance of biochar derived from rice straw for the removal of Ni(II) as a function of various environmental conditions. The results showed that Ni(II) sorption was strongly dependent on pH but independent of ionic strength and the effects of electrolyte ions could be negligible over the whole pH range. Ionic exchange and inner-sphere surface complexation dominated the sorption of Ni(II). Humic/fulvic acids clearly enhanced the Ni(II) sorption at pH <7.2 but inhibited the sorption at pH >7.2. The sorption reached equilibrium within 10 hours, and the kinetics followed a pseudo-second-order rate model. Any of the Langmuir, Freundlich, or Dubinin-Radushkevich isotherm models could describe the sorption well, but the Langmuir model described it best. The maximum sorption capacity calculated from the Langmuir model was 0.257 m·mol/g. The thermodynamic parameters suggested that Ni(II) sorption was a spontaneous and endothermic process and was enhanced at high temperature. The results of this work indicate that biochar derived from rice straw may be a valuable bio-sorbent for Ni(II) in aqueous solutions, but it still requires further modification.

Benthic microbial fuel cells (BMFCs) are considered to be one of the eco-friendly bioelectrochemical cell approaches nowadays. The utilization of waste materials in BMFCs is to generate energy and concurrently bioremediate the toxic metals from synthetic wastewater, which is an ideal approach. The use of novel electrode material and natural organic waste material as substrates can minimize the present challenges of the BMFCs. The present study is focused on cellulosic derived graphene-polyaniline (GO-PANI) composite anode fabrication in order to improve the electron transfer rate. Several electrochemical and physicochemical techniques are used to characterize the performance of anodes in BMFCs. The maximum current density during polarization behavior was found to be 87.71 mA/m² in the presence of the GO-PANI anode with sweet potato as an organic substrate in BMFCs, while the GO-PANI offered 15.13 mA/m² current density under the close circuit conditions in the presence of 1000 Ω external resistance. The modified graphene anode showed four times higher performance than the unmodified anode. Similarly, the remediation efficiency of GO-PANI was 65.51% for Cd (II) and 60.33% for Pb (II), which is also higher than the unmodified graphene anode. Furthermore, multiple parameters (pH, temperature, organic substrate) were optimized to validate the efficiency of the fabricated anode in different environmental atmospheres via BMFCs. In order to ensure the practice of BMFCs at industrial level, some present challenges and future perspectives are also considered briefly.

Nanostructures possess distinct quenching ability toward fluorophores with different emission frequencies and have been intensively used as nanoquenchers for homogeneous nucleic acid detection. Complete understanding of such a sensing system will provide significant guidance for the design of superior sensing materials, which is still lacking. In this Letter, we demonstrate the development of FeP nanowires as a nanoquencher for high-performance fluorescent nucleic acid detection with much superior performance to α-Fe₂O₃ counterparts. The whole detection process is complete within 1 min, and this fluorosensor presents a detection limit as low as 4 pM with strong discrimination of single-point mutation. Electrochemical tests and density functional theory calculations reveal that FeP NWs are superior in both conductivity for facilitated electron diffusion and hydrogen-evolving catalytic activity for favorable electron depletion, providing further experimental and theoretical insights into the enhanced sensing performance of the FeP nanosensor. Both faster electron transfer kinetics and stronger electron-consuming ability via catalyzed proton reduction enable FeP nanowires to be a superb nucleic acid nanosensor for applications.

Abstract Amino‐functionalized zirconium‐based metal‐organic frameworks (MOFs) have shown unprecedented catalytic activity compared to non‐functionalized analogues for hydrolysis of organophosphonate‐based toxic chemicals. Importantly, the effect of the amino group on the catalytic activity is significantly higher in the case of UiO‐66‐NH 2 , where the amino groups reside near the node, compared to UiO‐67‐ m ‐NH 2 , where they are directed away from the node. Herein, we show that the proximity of the amino group is crucial for fast catalytic activity towards hydrolysis of organophosphonate‐based nerve agents. The generality of the observed amine‐proximity‐dictated catalytic activity has been tested on two different MOF systems which have different topology. DFT calculations reveal that amino groups on all the MOFs studied are not acting as Brønsted bases; instead they control the microsolvation environment at the Zr 6 ‐node active site and therefore increase the overall catalytic rates.