In recent years, platinum-based single crystalline nanoalloys as nanoscale catalysts, such as Pt-M (M = Ni, Co, Fe..etc.), have exhibited improved catalytic performance due to the increase in the surface-to-volume ratio. Some Pt-M nanopolyhedra such as nanocubes and nano-octahedra have been reported with enhanced activity when being used as electrocatalysts. In order to further establish a correlation between the exposed nanocrystal facets (shapes) and their corresponding activities, a pursuit of shape-controlled nanocatalyst synthesis is essential. Although PtPb nanoalloys have been prepared using solution-based methods, few studies have highlighted their catalytic activity as a function of the nanocrystal shape. This work focuses on a modified polyol synthesis technique and an adjustment of the Pb-metal precursor, which serves as a “buffer” in the nucleation stage of the shape-controlled nanoalloy development. Using this developed synthetic strategy, shape-controlled hexagonally close-packed PtPb nanoalloys can be prepared in a one-pot synthesis without additional post-treatment. The as-prepared PtPb nanocrystals demonstrate an improved anode electrocatalytic performance.

Mesoporous carbon aerogel has been impregnated with iron (10 and 15 wt. %) as a catalyst for graphitization by wet incipient method. The iron modified and non-modified carbon aerogels were heat treated at 900°C, 1200°C, and 1400°C in argon. The crystal structure, morphology, and electro catalytic activity of the resulting nano-composites have been studied. It was found that, the degree of graphitization was proportional to the concentration of Iron phase and the ratio of iron to iron nitride phase in the heat-treated samples. In carbon aerogel sample sintered at 1200°C with 15 wt. % of iron phase, mesoporosity in the range of 3-4 nm and microporosity (< 2nm) was significantly improved by graphitization without affecting the Carbon Aerogels mesoporosity in 10-30 nm range. In this case of 15 wt. % iron doped samples, HRTEM analysis confirms the presence of uniformly distributed ∼43.5nm iron nanoparticles surrounded by graphene layers. Correspondingly, improved graphitization and presence of iron nitride resulted in 3.65 electron assisted oxygen reduction reaction.

Electrocatalytic activity and stability of platinum nanocubes and nanospheres were comparatively investigated towards methanol oxidation reaction. The results indicate that the {100}-bounded Pt nanocubes exhibit not only higher catalytic activity but also higher stability compared with the mixed crystallographic facet-terminated Pt nanospheres.

This work makes an attempt to correlate experimentally observed Tafel slopes from the oxygen reduction reaction in both model rotating disk electrode and polymer electrolyte fuel cell measurements, respectively, with the kinetic description of a coverage dependent current-potential relationship. It is shown that the potential dependent OHad coverage can be used as a descriptor of potential dependent Tafel slopes, pointing to the validity of underlying Temkin-Frumkin adsorption properties in combination with the Butler-Volmer approach.

Preferentially {100} oriented and polycrystalline platinum electrodes were prepared by potentiostatic electrodeposition. The surface of the electrodes was characterized by deconvolution of the hydrogen desorption region. The catalytic activity for formic acid oxidation was determined by cyclic voltammetry and chronoamperometry. The results indicate that although the maximum current observed in cyclic voltammogram does not increase, the long term performances as measured by chronoamperometry dramatically increase up to 33 times with increased Bi coverage despite the loss of electroactive Pt surface area.

The influence of electrodeposition parameters on chemical composition, morphology and functional properties of such binary cobalt alloys as CoAg, CoW, and CoFe has been investigated. The alloys are shown to possess catalytic properties. Catalytic activity was preliminary estimated in the electrolytic hydrogen evolution reaction and tested by CO to CO2 conversion during the catalytic benzene oxidation.

Charging of amorphous solid water (ASW) films has been characterized using high resolution, low energy positive ions (Ar+) and electrons at 1-50 eV energy range. This system responds to charging as a nano-capacitor and has been studied for its static electric field effect on electron-induced-desorption from top layers and internally trapped molecules within ASW film. In addition we have investigated the role of electron energy on chemical reactivity of trapped methyl chloride molecules as model for outer space surface chemistry.

Dynamic charging at inner pores of porous silicon (PSi) has been studied as the origin of highly efficient photo-induced desorption (PID) of adsorbates such as Xe, CO and N2O. Wavelength and laser power dependence suggest that cross sections for PID, 3 orders of magnitude larger than on non-porous surfaces, originate from dynamic charging of nanometer scale tips at inner pores. These have lead to transient negatively charged species that undergo an Antoniewitz-like PID mechanism.

Bi-functional oxygen electrodes are an enabling component for rechargeable metal-air batteries and regenerative fuel cells, both of which are regarded as the next-generation energy devices with zero emission. Nonetheless, at the present, no single metal oxide component can catalyze both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with high performance which leads to large overpotential between ORR and OER. This work strives to address this limitation by studying the bi-functional electrocatalytic activity of the composite of a good ORR catalyst compound (e.g. palladium oxide, PdO) and a good OER catalyst compound (e.g. ruthenium oxide, RuO2) in alkaline solution (0.1M KOH) utilizing a thin-film rotating disk electrode technique. The studied compositions include PdO, RuO2, PdO/RuO2 (25wt.%/75wt.%), PdO/RuO2 (50wt.%/50wt.%) and PdO/RuO2 (75wt.%/25wt.%). The lowest overpotential (e.g. E (2 mA cm−2) - E (-2 mA cm−2)) of 0.82 V is obtained for PdO/RuO2 (25wt.%/75wt.%) (versus Ag|AgCl (3M NaCl) reference electrode).

This work concerns the search for new electrode materials for efficient biofuel cells applications. Using a hard templating method we prepared carbonaceous electrodes modified further with Glucose Oxidase and Os polymer. The glucose electrooxidation current is 13-fold bigger on the porous electrode than on flat glassy carbon for the same enzyme loading. These electrodes are three dimensional and posses hierarchical porosity, to optimize the need for both surface area and efficient fuel delivery Although, the dependence of the catalytic current with the rotation rate suggests that the size and quantity of the macropores is not yet fully optimized, the electrode preparation protocol is simple and low cost, and can be easily adapted to tune the pore sizes. The mechanical strength and the synthetic route allow for the external shape and size of the electrodes to be designed on demand, an important feature to incorporate electrodes into devices.

At present, there is an ongoing search for approaches toward the storage of energy from intermittent renewable sources like wind and solar. Flow batteries have gained attention due to their potential viability for inexpensive storage of large amounts of energy. While the quinone/hydroquinone redox couple is a widely studied redox pair, its application in energy storage has not been widely explored. Because of its high reversibility, low toxicity, and low component costs, we propose the quinone/hydroquinone redox couple as a viable candidate for use in a grid-scale storage device. We have performed single-electrode tests on several quinone/hydroquinone redox couples, achieving current densities exceeding 500 mA/cm2, which is acceptable for use in energy applications. We fabricated a full cell using para-benzoquinone at the positive electrode against a commercial fuel cell hydrogen electrode separated by a Nafion membrane. We evaluated its performance in galvanic mode, where it reached current densities as high as 150 mA/cm2. The results from these studies indicate that the quinone/hydroquinone redox couple is a promising candidate for use in redox flow batteries.

Energy storage is a key technology for establishing a stand-alone renewable energy system. Current energy-storage technologies are, however, not suitable for such an energy system. They are cost ineffective and/or are with low energy-conversion efficiency. Hydrogen generation and storage from water by sunlight is one of these technologies. In this study, a simple concept of hydrogen generation from water by using sunlight, “concentrated photovoltaic electrochemical cell (CPEC)” is proposed. It is experimentally shown that the CPEC operates stably and achieves conversion efficiency from light to hydrogen energy of over 12%.

The design of clean, efficient and environmentally friendly routes that reduce the waste production and fuel emissions of pollutants into the atmosphere, produce clean, affordable, and renewable energy sources to lessen energy consumption and toxicity on the environment, has become a central issue of chemical research both in industry and academia. One of the approaches being used in green chemistry practices is to use water as a solvent and reaction medium where possible. Much of this work deals with liquid water at temperatures exceeding the normal boiling point which is denoted as sub-critical water.

Electrochemical reaction, usually operated at atmospheric condition in water, is generally slow, although it has advantages over chemical reaction such as suppression of side reaction by tuning operating conditions. Since sub-critical water (7 MPa and 250 °C) has remarkable properties such as high ion product and low dielectric constant, it could be a suitable reaction media.

We have been studying electrolysis of organic compounds in sub-critical water as waste treatment and molecular degradation technologies. Electrolysis in sub-critical water could degrade harmful and thermally stable organic compounds into innocuous compounds such as hydrogen and water. In this research, we focused on the investigation of the electrochemical reactions of alcohols in sub-critical water to evaluate possibility for the selective production of hydrogen and value-added chemicals.

Electrochemical reactions were carried out in sub-critical water using a specially designed autoclave made of SS 316 with a volume of 500 mL. For comparison, thermal degradation experiments of alcohols were also conducted without any direct current loading at identical conditions. Here we employed glycerol and 1-butanol as model compounds of alcohols.

As a result of 1-butanol experiments, butanal and butyric acid were produced via partial oxidation at 250 °C and by applying 1-3 A of direct current while no oxidation products were observed at the hydrothermal degradation run. As a gaseous product, hydrogen gas was generated according to the electrochemical reaction mechanism. In the case of glycerol experiments, the main gaseous product was hydrogen gas, whereas glycolaldehyde, lactic acid, and formic acid were generated as the main liquid products at 280 °C. Results indicated that greater than 92% of the glycerol could be decomposed under optimum conditions by hydrothermal electrolysis technique.

This presented research will help to degrade stable organic materials in an environmentally friendly way and without need for secondary treatment processes. It will also address the need for novel more efficient techniques for the degradation of stable organic compounds in aqueous conditions and it will advance the use of water as a reaction medium in an efficient way without any organic solvent.

This investigation describes preliminary results of in-situ analysis of zinc deposition within an ionic liquid electrolyte utilizing electrochemical atomic force microscopy (EC AFM). From the AFM analysis, the morphology of the zinc deposition was analyzed by quantifying the surface roughness using height-height correlation functions. These results will be used to analyze the scattering data obtained from zinc deposition analysis utilizing an electrochemical ultra-small angle x-ray scattering (EC USAXS). The goal of this research is to link the early nucleation and growth behavior to the formation of detrimental morphologies.