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Nanoporous Materials Miniaturized ReactorsNational Cheng Kung UniversityDepartment of Chemical Engineering

MCM Carbon/metal redox center

Gas-carbon

> 3000 m2/g

predict

Application of Porous Carbon in Supercapacitors (Electrochemical Capacitors)a. GasificationRaw Material char Porous Carbon

b. Chemical impregnationRaw Material slurry Porous carbon

c. Etching Raw Material partially etched Porous carbonin N2in H2O or CO2mixingZnCl2 or H3PO4in N2leachingHClin N2mixingalkalileachingHClcarbonizationgasification (activation)

Electrochemical Capacitors Have High Power Density and Energy CapacityR. Ktz, M. Carlen, Electrochimica Acta 45 (2000) 24832498

Principle of Energy StorageConventional capacitors

The larger area the electrodes can provide, the more energy can be stored.Carbon can be made with high surface area and porosity.

d = 5 10 Double Layer Capacitor

Conventional Capacitors

Double Layer Capacitors

(small d of double Layer) + (porous electrode) Very high capacitancee.g.S.A. = 1000 m2/g for porous carbondouble-layer capacitance = 10 F/cm2 100 F/gfor capacitors with carbon electrodes;more than 1000 times higher than conventional capacitors.

Principle of Operation

a. (backup source) (global system for mobile communication, GSM): 5 ms0.5 mspulse powerEC

b. ,

c.

d. /

Template Synthesis Method - Principle and Application

Preparation of Ordered Mesoporous Carbon and ApplicationsMesoporous silica, like MCM48, SBA15, etc,has been used to synthesis ordered mesoporous carbon in recent years.Compare with traditional active carbon, mesoporous carbon not only reserves high specific surface (ca. 1500 cm2/g), but also has uniform pore size and regular nanostructure.It can be used as catalytic supports, electrode materials, etc.

Synthesis

Mechanismcarbonization

TEM image and SBETSBET = 1784 cm2/g

ApplicationsAnodic catalyst support for direct methanol fuel cell (DMFC).Electrochemical double layer capacitor.Separation and purification technology.

Materials(a) Track etch membranes :

(b) Porous alumina membranespolymerIon beamPorous membranetrack-etched PC membraneAnodic Alumina Oxide membranePore diameter = 0.2 mPore diameter = 5 nm

(a) cross-section of raw membrane (b) Sn2+ coated template membrane (c) electroless deposition of Ni-P (d) dissolution of the template membrane. Experimental

Characterization of As-deposited Ni-P Films -1SEM images of Ni-P electrode arrays

pore internal external tubule area

diameter diameter diameter length increase

(m) (m) (m) (m)

0.2 0.18 0.22 2.0 8.8 times

Ni(OH)2 + OH- -> NiOOH + H2O + e-NiOOH + H2O + e- -> Ni(OH)2 + OH-Characterization of As-deposited Ni-P Films -2

Preparation of Nanotube-shaped TiO2 and ApplicationsSince the discovery of carbon nanotubes in 1991 by Iijima, much research has been conducted on nanoscale tubular materials with novel propertiesTiO2 is wide application in pigments, catalyst supports, fillers, coating, photoconductors, dielectric materials and so on.TiO2 has good characteristics of chemical stability, endurance, thin film transparency and lower production costs.

Hydrothermal MethodTiO2 powdersNaOH(aq)Heat in autoclaveWash with HCl(aq) and D.I. waterultrasonicFiltering and DryingAnalysis with XRDTEMBETetc.

TEM Images

Nitrogen Adsorption

SBET (m2/g)Vp (cm3/g)3701.188

MechanismRaw material treates with NaOH(aq), some of the Ti-O-Ti bonds are broken, and Ti-O-Na and Ti-OH bonds are formed.2. Treated with HCl (aq) and distilled water, the Ti-O-Na and Ti-OH bonds react with acid and water to form new Ti-O-Ti bonds. 3. More HCl(aq) treatment

ApplicationsLarge surface area offer a highly active photo-catalytic material for many applications.High efficient dye-sensitized solar cell.Provide a functional catalyst for chemical reaction, and an adsorbents for chemicals.Environmental purification.Generation of hydrogen gas.