Yituo Wang

An oxygen evolution catalyst on an antimony doped tin oxide nanowire structured support for proton exchange membrane liquid water electrolysis

Developing catalysts with high electrocatalytic activity has recently attracted much attention due to the slow reaction kinetics for oxygen evolution reaction (OER) and poor durability under harsh operating environments. Aiming at the enhancement of oxygen electrode kinetics and durability, a facile and scalable electrospinning method is employed to fabricate antimony doped tin oxide nanowires (Sb–SnO2 NWs) as support materials for iridium oxide. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results show that the as-prepared Sb–SnO2 NW is stacked from primary Sb–SnO2 nanoparticles (Sb–SnO2 NPs) with diameters of 15–25 nm and exhibits a uniform porous nanowire structure with diameters in the range of 200–300 nm. The synthesized Sb–SnO2 NW has a BET surface area of 60 m2 g−1 and an electronic conductivity of 0.83 S cm−1. Benefiting from the porous nanowire structure and high electronic conductivity of the Sb–SnO2 NW support, the supported IrO2 catalyst exhibits significant enhancement of mass activity toward OER in acidic electrolytes compared with that of Sb–SnO2 NP supported IrO2 catalyst and pure IrO2. The improved catalytic performance for OER is further confirmed by proton exchange membrane (PEM) electrolyzer tests at 80 °C. A test of such an electrolyzer cell at 450 mA cm−2 shows good durability within a period of up to 646 h.

Nafion®/SiO2/m-BOT composite membranes for improved direct methanol fuel cell performance

Bentonite (BOT) has excellent hygroscopicity and large specific surface, so it is chosen as a dopant of Nafion® membranes in this paper. By using the sol–gel method, bentonite has been modified by dodecylamine and fixed to the Nafion 212 membrane to prepare a Nafion/SiO2/m-BOT composite membrane. The results of SEM and FT-IR shows that m-BOT is successfully synthesized and bound well with the Nafion 212 membrane. The limiting current density of cathode methanol oxidation indicates that the methanol permeability of the composite membrane is 20.40% lower than that of the Nafion 212 membrane. Although the conductivity of the composite membrane (6.67 × 10−2 S cm−1) declines slightly compared with that of Nafion 212 (9.91 × 10−2 S cm−1), the performance of the cell using the composite membrane (135.17 mW cm−2) is better than the Nafion 212 membrane (118.7 mW cm−2) at 55 °C. Besides, as the anode methanol concentration increases, higher performance is obtained, which indicates that the composite membrane is more suitable for cells running with a high concentration of methanol.