Chemical and electrochemical corrosion of a support limits the corresponding catalyst's performance and lifetime. In this paper, uniform TiN nanotubes are synthesized via coaxial-electrospinning, thermal oxidation and nitridation. The average diameter of nanotubes can be facilely controlled by tuning the parameters of coaxial electrospinning. The TiN nanotubes are modified further with Pt nanoparticles as Pt/TiN NT electrocatalysts. After accelerated durability tests, the electrochemical surface area (ECSA) and mass activity of the Pt/TiN decrease by only 6% and 14% respectively, while those of the Pt/C decrease by 44% and 46.2% respectively. The enhanced activity is attributed to the strong interaction between the Pt nanoparticles and the TiN support, which is confirmed by the X-ray dispersive spectra of Pt 4f.

An anode catalytic layer for direct methanol fuel cells (DMFCs) with decreased PtRu loading as low as 1.0 mg cm−2 has been prepared by an electrospray method. The morphology of the electrosprayed composite of PtRu/C/Nafion/polyethylene oxide (PEO) is altered from irregular particles to porous microspheres and to nanofibers by adjusting the PEO content. A hybrid structure is assembled using the porous microspheres as the anode catalytic layer for DMFCs, leading to a remarkable enhancement in the maximum power density of 35.4 mW cm−2, which is ∼50% higher than that of the conventional one at the same PtRu loading of 1.0 mg cm−2 and is even comparable to that (31.5 mW cm−2) of the conventional one at a higher PtRu loading of 2.0 mg cm−2. Further investigation reveals that the improved performance is mainly attributed to its hierarchical factual structure. In the primary structure, a single microsphere is with well-distributed PtRu/C and is fully rich in nano-pores and nano-channels, resulting in an increase in the electrochemical active surface area and higher catalyst utilization. In the secondary structure, micro-sized pathways are formed by the stereoscopic microspheres, resulting in enhanced mass transport, higher current density and power density.

•A nanofiber network catalytic structure (NNCL) is used in the anode of a DMFC.•The use of the NNCL leads to a significant increase in catalyst utilization.•The DMFC with 55% reduced anode catalyst loading exhibits a comparable performance.A novel membrane electrode assembly (MEA) that utilizes a nanofiber network catalytic layer (NNCL) structure in the anode of a passive direct methanol fuel cell (DMFC) leads to a significant decrease in noble metal catalyst loading of a DMFC. When the PtRu (1:1) loading within the NNCL is 1.0 mg cm−2, the maximum power density of a DMFC is ca. 33.0 ± 1.9 mW cm−2, which is even slightly higher than that with a conventional MEA with a PtRu loading of 2.0 mg cm−2. Electrochemical tests show that such a NNCL exhibits a great increase in catalyst utilization and a decrease in charge-transfer resistance of the anode in comparison with the conventional MEA. The improved performance of the novel MEA is definitely due to the formation of the nanofiber network structure in the anode. This study provides a promising way to decrease the utilization of the noble metal catalysts for the proton exchange membrane fuel cells.

In this paper a simple and rapid fabrication method for a microfluidic direct methanol fuel cell using polydimethylsiloxane (PDMS) as substrate is demonstrated. A gold layer on PDMS substrate as seed layer was obtained by chemical plating instead of conventional metal evaporation or sputtering. The morphology of the gold layer can be controlled by adjusting the ratio of curing agent to the PDMS monomer. The chemical properties of the gold films were examined. Then catalyst nanoparticles were grown on the films either by cyclic voltammetry or electrophoretic deposition. The microfluidic fuel cell was assembled by simple oxygen plasma bonding between two PDMS substrates. The cell operated at room temperature with a maximum power density around 6.28 mW cm−2. Such a fuel cell is low-cost and easy to construct, and is convenient to be integrated with other devices because of the viscosity of the PDMS. This work will facilitate the development of miniature on-chip power sources for portable electronic devices.

A novel cathode catalyst layer with discontinuous hydrophobicity gradient distribution is designed and fabricated for passive direct methanol fuel cells (DMFCs). The stepwise hydrophobicity distribution is beneficial to the oxygen diffusion inside the cathodic catalytic layer and to the water removal from the cathode, thus improving the performance and stability of the DMFC. The DMFC with the above-mentioned novel cathodic catalytic layer structure presents a maximum power density of 33.5 mW cm–2 at a temperature of ca. 25 °C, while the DMFC with a conventional structure only gives 27.4 mW cm–2 under the same operating conditions. The enhanced performance of the DMFC with such a novel cathode structure might be attributed to a decreased charge-transfer resistance for the oxygen reduction reaction on the cathode.

An anode catalytic layer for direct methanol fuel cells (DMFCs) with decreased PtRu loading as low as 1.0 mg cm−2 has been prepared by an electrospray method. The morphology of the electrosprayed composite of PtRu/C/Nafion/polyethylene oxide (PEO) is altered from irregular particles to porous microspheres and to nanofibers by adjusting the PEO content. A hybrid structure is assembled using the porous microspheres as the anode catalytic layer for DMFCs, leading to a remarkable enhancement in the maximum power density of 35.4 mW cm−2, which is ∼50% higher than that of the conventional one at the same PtRu loading of 1.0 mg cm−2 and is even comparable to that (31.5 mW cm−2) of the conventional one at a higher PtRu loading of 2.0 mg cm−2. Further investigation reveals that the improved performance is mainly attributed to its hierarchical factual structure. In the primary structure, a single microsphere is with well-distributed PtRu/C and is fully rich in nano-pores and nano-channels, resulting in an increase in the electrochemical active surface area and higher catalyst utilization. In the secondary structure, micro-sized pathways are formed by the stereoscopic microspheres, resulting in enhanced mass transport, higher current density and power density.