Polytetrafluoroethylene ptfe

La(NO₃)₃·6H₂O (98+%, Fisher
Scientific), Co(NO₃)₂·6H₂O (99%,
Fisher Scientific),
Cr(NO₃)₂·6H₂O (99%, Fisher Scientific),
and Fe(NO₃)₃·9H₂O (99+%, Fisher
Scientific) were used as metal precursors with no further purification.
Citric acid (99+%, Sigma-Aldrich) and ethylene glycol (Alfa Aesar)
were used during the synthesis process. Carbon black (Vulcan XC-72R)
was used as a highly conductive material. Pt/C was commercially purchased
(commercial 20 wt % platinum on carbon black, Fuel Cell Store). Carbon
cloth (Fuel Cell Store) was used as the diffusion substrate layer
for fuel cell tests along with a 20 μm PiperION-A20-HCO3 TP-85
membrane (Versogen) and PiperION BP-100 ionomer (Versogen). Polytetrafluoroethylene
(PTFE) was purchased as a suspension from Sigma-Aldrich and used as
the hydrophobic agent. Other chemicals such as isopropanol and KOH
were all analytical grade reagents purchased from Alfa Aesar.

Toray carbon paper (TGP-H-60)
without PTFE treatment was purchased from Alfa Aesar. Sulfuric acid
(95–98% H₂SO₄), polytetrafluoroethylene
(PTFE) 60 wt % dispersion in water, polyvinyl alcohol (PVA) powder M_w = 146,000–186,000, KOH pellet, and
Nafion perfluorinated resin solution (5 wt %) were purchased from
Sigma-Aldrich. 30 wt % H₂O₂ was purchased from
Lanchner. Ethanol (absolute) was purchased from Penta. Commercial
TiN nanocubes were obtained from PlasmaChem GmbH (average size ∼
50 nm). All aqueous solutions were prepared with ultrapure water (18
MΩ cm^–1). All the chemicals and materials
were used without further treatment.

Hydrogen peroxide (30% weight) was used along with 99.9% pure Mo powder and 99% pure hexamethylenetetramine (HMTA) purchased from Sigma-Aldrich. Sodium hypophosphite (NaH₂PO₂) (98–101% weight, Sigma-Aldrich), polytetrafluoroethylene (PTFE) (60% weight, Sigma-Aldrich), potassium hydroxide (KOH, 85–90% weight), and Ni foam (99.9% purity, MTI Corporation). All chemicals were used without any further purification.

KOH (Merck, pellets), HCl (Merck,
37%), H₂SO₄ (VWR, 95%), acetone (VWR chemicals),
and isopropanol (VWR, 98%)
were purchased and used as received. Glass microfiber filters (GF/A
from Whatman) were punched out (⌀ 10 mm) and used as separator
in a Swagelok T-cell. LOCTITE EDAG PF 407C
(Henkel, Düsseldorf, Germany) was used as a conductive adhesive
to glue electrodes onto the stainless steel bolts. YP80 F from Kuraray
and poly(tetrafluoroethylene) (PTFE) from Sigma-Aldrich were used.

Zinc nitrate hexahydrate (98.0%), polytetrafluoroethylene (PTFE) (99.9%), and activated carbon (density 1.8–2.1 g cm⁻³, particle size 100 mesh) were supplied by Sigma Aldrich. Cobalt nitrate hexahydrate (98.0%), sodium sulfide (98.0%), potassium hydroxide (85.0%, pellets), carbon black (99.9%), and Whatman filter paper (180 μm thick, pore size 11 μm) were obtained from Alfa Aesar. Ammonium fluoride (99.9%) and urea (99.0%) were procured from Junsei. Ethanol (99.9%), hydrochloric acid (35.0–37.0%), and acetone (99.9%) were acquired from Duksan Pure Chemical. Ni foam was purchased from MTI cooperation (New York, NY, USA).

Iron(II) chloride tetrahydrate (FeCl₂·4H₂O, ≥99%), oxalic acid dihydrate (H₂C₂O₄·2H₂O, ≥99%), and lithium carbonate (Li₂CO₃, ≥99%) were purchased from Sigma-Aldrich. Li foil (thickness of ~100 μm), poly(tetrafluoroethylene) (PTFE, 1 μm powder size), conductive carbon black, propylene carbonate (PC), ethyl carbonate (EC), dimethyl carbonate (DMC) were purchased from Sigma-Aldrich. Kynar Flex 2801 (a copolymer based on polyvinylidene fluoride PVDF) binder was purchased from Arkema Group. The glass fiber separator (Whatman, 47 mm) was purchased from Shanghai Huanao Technology Ltd. All chemicals were used directly as received without further processing.