I have extensive knowledge in inorganic material science and electrochemistry, and highly skillful in characterizing material properties using electrochemical methods and exploring material's electrochemical applications.
August 2017 - August 2018
May 2014 - August 2017
August 2012 - December 2017
GPA: 3.9 / 4.0
Dissertation:“Mechanistic Study of Electrochemical Processes on A Porous Magnéli Phase Electrode”
August 2010 - July 2012
GPA: 3.8 / 4.0
Dissertation: “Computer Simulation of A Plug Flow Reactor for Cobalt Catalyzed Fischer Tropsch Synthesis Using A Microkinetic Model”
September 2005 - June 2009
The detection of hydroxyl radicals (OH•) is typically accomplished by using reactive probe molecules, but prior studies have not thoroughly investigated the suitability of these probes for use in electrochemical advanced oxidation processes (EAOPs), due to the neglect of alternative reaction mechanisms. In this study, we investigated the suitability of four OH• probes (coumarin, p-chlorobenzoic acid, terephthalic acid, and p-benzoquinone) for use in EAOPs. Experimental results indicated that both coumarin and p-chlorobenzoic acid are oxidized via direct electron transfer reactions, while p-benzoquinone and terephthalic acid are not. Coumarin oxidation to form the OH• adduct product 7-hydroxycoumarin was found at anodic potentials lower than that necessary for OH• formation. Density functional theory (DFT) simulations found a thermodynamically favorable and non-OH• mediated pathway for 7-hydroxycoumarin formation, which is activationless at anodic potentials > 2.10 V/SHE. DFT simulations also provided estimates of E° values for a series of OH• probe compounds, which agreed with voltammetry results. Results from this study indicated that terephthalic acid is the most appropriate OH• probe compound for the characterization of electrochemical and catalytic systems.
This research focused on the synthesis, characterization, and performance testing of a novel Magnéli phase (TinO2n–1), n = 4 to 6, reactive electrochemical membrane (REM) for water treatment. The REMs were synthesized from tubular asymmetric TiO2 ultrafiltration membranes, and optimal reactivity was achieved for REMs composed of high purity Ti4O7. Probe molecules were used to assess outer-sphere charge transfer (Fe(CN)64–) and organic compound oxidation through both direct oxidation (oxalic acid) and formation of OH• (coumarin, terephthalic acid). High membrane fluxes (3208 L m–2 h–1 bar–1 (LMH bar–1)) were achieved and resulted in a convection-enhanced rate constant for Fe(CN)64– oxidation of 1.4 × 10–4 m s–1, which is the highest reported in an electrochemical flow-through reactor and approached the kinetic limit. The optimal removal rate for oxalic acid was 401.5 ± 18.1 mmol h–1 m–2 at 793 LMH, with approximately 84% current efficiency. Experiments indicate OH• were produced only on the Ti4O7 REM and not on less reduced phases (e.g., Ti6O11). REMs were also tested for oxyanion separation. Approximately 67% removal of a 1 mM NO3– solution was achieved at 58 LMH, with energy consumption of 0.22 kWh m–3. These results demonstrate the extreme promise of REMs for water treatment applications.
Porous, flexible, reactive electrochemical membranes (REMs) for water purification were synthesized by a novel simultaneous electrospinning/electrospraying (E/E) technique, which produced a network of poly(sulfone) fibers and Ti4O7 particles as evidenced by scanning electron microscopy. Cyclic voltammetry indicated that the kinetics for water electrolysis reactions and the Fe(CN)64−/3− redox couple were enhanced by Ti4O7 deposition using the E/E technique. Membrane filtration experiments using phenol as a model contaminant showed a 2.6‐fold enhancement in the observed first‐order rate constant for phenol oxidation (kobs,phenol) in filtration mode relative to cross‐flow operation. Phenol oxidation in filtration mode was approaching the pore diffusion mass transfer limit, and was 6 to 8 times higher than measured in a previous study that utilized a ceramic Ti4O7 REM operated in filtration mode and is comparable to rate constants obtained with carbon nanotube flow‐through reactors, which are among the highest reported in the literature to date.
This paper demonstrated the fabrication of a facile, low-cost, and self-powered platform for point-of-care fitness level and athletic performance monitoring sensor using electrochemical lithography method and its application in body fluid sensing. Flexible Au/prussian blue electrode was employed as the indicating electrode, where the color change was an indication of fitness level and athletic performance. A piece of Al foil, Au/multiwalled carbon nanotubes (MWCNTs)-glucose dehydrogenase, and Au/polymethylene blue-MWCNTs-lactic dehydrogenase electrodes were used for the detection of ionic strength, glucose, and lactic acid in sweat, respectively, which allows the sensor to work without any extra instrumentation and the output signal can be recognized by the naked eyes. The advantages of these sensors are (1) self-powered; (2) readily applicable to the detection of any electroactive substance by an electrochromic material; (3) easy to fabricate via two steps of EDP; and (4) point-of-care. By assembling the energy and sensing components together through a transparent adhesive tape, the proposed self-powered wearable biosensor exhibits superior performances, indicating its broad applied prospect in the point-of-care diagnoses.
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