Electrophoretic Deposition on Porous Non-Conductors

A method of electrophoretic deposition (EPD) on substrates that are porous and electrically non-conductive has been invented. Heretofore, in order to perform an EPD, it has been necessary to either (1) use a substrate material that is inherently electrically conductive or (2) subject a non-conductive substrate to a thermal and/or chemical treatment to render it conductive. In the present method, instead of relying on the electrical conductivity of the substrate, one ensures that the substrate is porous enough that when it is immersed in an EPD bath, the solvent penetrates throughout the thickness, thereby forming quasi-conductive paths through the substrate. By making it unnecessary to use a conductive substrate, this method simplifies the overall EPD process and makes new applications possible. The method is expected to be especially beneficial in enabling deposition of layers of ceramic and/or metal for chemical and electrochemical devices, notably including solid oxide fuel cells

Graphene Coating on Copper by Electrophoretic Deposition for Corrosion Prevention

In this paper, we report the use of a simple and inexpensive electrophoretic deposition (EPD) technique to develop thin, uniform, and transparent graphene oxide (GO) coating on copper (Cu) substrate on application of 10 V for 1 s from an aqueous suspension containing 0.03 wt % graphene oxide. GO was partially reduced during the EPD process itself. The GO coated on Cu was completely reduced chemically by using sodium borohydride (NaBH4) solution. The coatings were characterized by field emission scanning electron microscope (FESEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), XRD, and UV/VIS spectrophotometry. Corrosion resistance of the coatings was evaluated by electrochemical measurements under accelerated corrosion condition in 3.5 wt % NaCl solution. The GO coated on Cu and chemically reduced by NaBH4 showed more positive corrosion potential (Ecorr) (−145.4 mV) compared to GO coated on Cu (−182.2 mV) and bare Cu (−235.3 mV), and much lower corrosion current (Icorr) (7.01 µA/cm2) when compared to 15.375 µA/cm2 for bare Cu indicating that reduced GO film on copper exhibit enhanced corrosion resistance. The corrosion inhibition efficiency of chemically reduced GO coated Cu was 54.40%, and its corrosion rate was 0.08 mm/year as compared to 0.18 mm/year for bare copper

Electrophoretic Deposition of Ti3SiC2 and Texture Development in a Strong Magnetic Field

this study,we have shown the applicability of electrophoretic deposition (EPD) for shape-forming in Ti3SiC2—a representative MAX phase; and viability of texture development thereof by application of a strong magnetic field (12 T). The dispersion characteristics of Ti3SiC2 suspension were investigated in terms of surface charge, rheological measurement, and adsorption study. Polyethyleneimine has been used as dispersant to stabilize the suspension. It was found that the iso-electric point (IEP) of Ti3SiC2 powder was pHIEP ~ 4. The surface charge of powder changed in presence of the Polyethyleneimine dispersant and IEP shifted significantly towards basic pH ~ 10. The shift in IEP has been quantified in terms of DG0 SP, the specific free energy of adsorption between the surface sites and the adsorbing polyelectrolyte (PEI) (The value of DG0 SP obtained is 9.521 RT units). The optimized suspension parameters for EPD were determined as 10 vol% Ti3SiC2 and 1 dwb PEI in 50% ethanolic water at pH ~ 7. X-ray diffraction analysis of the textured samples developed, revealed that the preferred orientation of Ti3SiC2 grains parallel to the magnetic field direction was along the a, b-axis (The Lotgering orientation factors on the textured top surface and textured side surface were determined as fL(hk0) = 0.35 and fL(00l) = 0.75, respectively)

Enhanced Photocatalytic Activity and Charge Carrier Dynamics of Hetero-Structured Organic–Inorganic Nano-Photocatalysts

P3HT-coupled CdS heterostructured nanophotocatalysts have been synthesized by an inexpensive and scalable chemical bath deposition approach followed by drop casting. The presence of amorphous regions corresponding to P3HT in addition to the lattice fringes [(002) and (101)] corresponding to hexagonal CdS in the HRTEM image confirm the coupling of P3HT onto CdS. The shift of π* (CC) and σ* (C–C) peaks toward lower energy losses and prominent presence of σ* (C–H) in the case of P3HT–CdS observed in electron energy loss spectrum implies the formation of heterostructured P3HT–CdS. It was further corroborated by the shifting of S 2p peaks toward higher binding energy (163.8 and 164.8 eV) in the XPS spectrum of P3HT–CdS. The current density recorded under illumination for the 0.2 wt % P3HT–CdS photoelectrode is 3 times higher than that of unmodified CdS and other loading concentration of P3HT coupled CdS photoelectrodes. The solar hydrogen generation studies show drastic enhancement in the hydrogen generation rate i.e. 4108 μmol h^–1g^–1 in the case of 0.2 wt % P3HT–CdS. The improvement in the photocatalytic activity of 0.2 wt % P3HT–CdS photocatalyst is ascribed to improved charge separation lead by the unison of shorter lifetime (τ₁ = 0.25 ns) of excitons, higher degree of band bending, and increased donor density as revealed by transient photoluminescence studies and Mott–Schottky analysis