The electrochemical reduction of highly oxidized unsupported graphene oxide nanosheets and its platinum electrodeposition was done by the rotating disk slurry electrode technique. Avoiding the use of a solid electrode, graphene oxide was electrochemically reduced in a slurry solution with a scalable process without the use of a reducing agent. Graphene oxide nanosheets were synthesized from carbon platelet nanofibers to obtain highly hydrophilic layers of less than 250 nm in width. The graphene oxide and electrochemically reduced graphene oxide/Pt (erGOx/Pt) hybrid materials were characterized through different spectroscopy and microscopy techniques. Pt nanoparticles with 100 facets, clusters, and atoms at erGOx were identified by high resolution transmission electron microscopy (HRTEM). Cyclic voltammetry was used to characterize the electrocatalytic activity of the highly dispersed erGOx/Pt hybrid material toward the oxidation of ammonia, which showed a 5-fold current density increase when compared with commercially available Vulcan/Pt 20%. This is in agreement with having Pt (100) facets present in the HRTEM images of the erGOx/Pt material.

In this work, we developed an alternative manufacturing paper-based microfluidics method through 3D printing and wax filament. Microfluidic paper-based analytical devices (μPADs) are low-cost and easy-to-manufacture tools used for various chemical and biological analyses and studies. Paper-based microfluidics with wax has been limited as the manufacturers have discontinued most wax printing equipment. We aim to develop a low-cost and accessible manufacturing method that can replace conventional wax-on paper-based microfluidic manufacturing methods. Using highly available commercial 3D printing technology and wax filament, we could create hydrophobic wax barriers on the surface of different paper types. The properties and limits of this manufacturing method were characterized. Moreover, using this paper-based microfluidic manufacturing method, we were able to measure dopamine electrochemically using μPAD as a passive flow-based method in concentrations as low as 1 nM using injections as small as 15 μL.

Boron-doped diamond (BDD) was prepared in nanosize particles and they were used as a support for noble metal-based nanoparticles. Nanosize platinum oxide was deposited on diamond nanoparticles as well as on boron-doped diamond nanoparticles by the sol–gel method. Cyclic voltammetric results showed an improvement in conductivity as well as in surface capacitance when diamond nanoparticles were doped with boron. The X-ray photoelectron spectroscopy boron binding energy peak showed , which is consistent with the electrochemical characterization. Platinum oxide deposition was studied by cyclic voltammetry with an improvement when BDD nanoparticles were used as a support.