Carbide-derived Carbon (CDC) has been demonstrated to be an excellent electrode material for electrochemical devices including supercapacitors due to its chemical and electrochemical stability, large specific surface area and controllable pore size and morphology. Currently, CDC is prepared from metal carbides by chlorination in a chlorine gas atmosphere at temperatures of 350 • C or higher. In this paper, conversion using electrochemical methods is reported, which can be achieved by oxidizing vanadium carbides (VC or V 2 C) in aqueous solutions at room temperature and a mild electrode potential to prepare CDC thin film as electrode materials for "on-chip" supercapacitiors. It was found that VC and V 2 C can both be oxidized at a potential of about 0.4 V vs. Ag/AgCl or higher in neutral, acidic, or basic solutions. After the oxidation, vanadium is readily detected in the electrolyte solutions by ICP-MS (Inductively Coupled Plasma -Mass Spectrometry). The so-produced CDC thin film electrode (ca. 2.0 -2.6 μm thick) has a porous morphology and bears specific double layer capacitance values as high as 0.026 F.cm −2 (or 130 F.cm −3 ) with some dependence on the oxidation potential, time, and electrolyte solutions. Carbide-Derived carbon (CDC) is a new type of porous carbon material demonstrating high purity, a narrow distribution of pore sizes, and significant specific surface area.1,2 Due to these unique properties, CDC was found to be very useful for gas storage, flow sensors, and as an electrode material for electrochemical energy storage devices such as supercapacitors.3-7 Currently, the most reliable method to synthesize CDC is to remove the metal or metalloid elements selectively from binary or ternary carbide precursors. 1,8,9 This has been achieved by chlorine gas treatment (chlorination) at a temperature of 350• C or higher. At an elevated temperature, metal / metalloid elements can be reacted to be volatile metal chlorides and purged using an argon gas stream. Thus, the left-over carbon is metal free and sp 2 or sp 3 hybridized. To date, CDC has been successfully synthesized from binary carbides such as TiC, Cr 3 C 2 , Fe 3 C, Mo 2 C, Nb 2 C, SrC 2 , Ta 2 C, VC, V 2 C WC, W 2 C, ZrC, as well as ternary carbides (also called MAX phase carbides) such as Ti 2 AlC, Ti 3 AlC 2 . Most of this work has been performed in bulk solids/powders. Depending on the crystalline/ elemental structure of the precursor and the reaction temperature, the pore size of CDC can be controlled in the range over 2-50 nm.1 The theoretical bulk porosity is between 50-90% in volume. Thus far, the Cl 2 reaction method of etching has been primarily used but one downside is that the Cl 2 gas is toxic, corrosive and the process itself is relatively expensive. On the other hand, an alternative oxidation method is to prepare CDC under more environmentally favorable conditions that have been rarely explored. For example, Y. Gogotsi and coauthors reported the electrochemical etching of MAX-phase carbides to produce CDC at room temperature using ...

Acetic acid (HOAc) is a typical weak Brønsted acid that has been broadly used as a reactant in esterification reactions and can be used as such in ionic liquid (IL) solutions. The nature of the HOAc molecule as a solute in the IL 1-ethyl-3-methylimidazolium acetate (EMIMOAc) solutions was investigated with thermodynamic, vibrational spectroscopic, conductivity, and viscosity measurements. Calorimetry and vapor pressure-based thermodynamic measurements of the binary HOAc-EMIMOAc mixture were used to quantify the exothermic enthalpy of solution, H sol , as ~3.2-4.9 kJ/mol. FTIR and Raman spectroscopy showed that the structures of the HOAc molecule and IL molecular ions are unchanged in the solutions relative to the pure liquids, indicating that the HOAc is a negligibly-dissociated weak acid in the IL solutions. Temperaturedependent conductivity measurements quantify the effects of the HOAc on the IL solution conductivity and confirm that the HOAc remains a mostly neutral molecular solute that interacts with the EMIMOAc IL via ion-dipole and hydrogen bond interactions.