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This study describes an atomic layer deposition (ALD) approach for the fabrication of Pt nanocatalysts supported on graphene oxide (GO) sheets and their electrocatalytic performance in electro-oxidation of formic acid. The ALD process for forming the Pt atomic layer involves two self-limiting reactions and, thus, induces the decoration of ALD-Pt on the edges of GO sheets with the presence of dangling bonds and oxygen functionalities. The resultant ALD-Pt catalyst on GO sheets offers better catalytic activity, CO tolerance, and long-term stability than those on commercial carbon support. On the basis of the results, the ALD approach described here can be applied to the design of novel catalytic materials for a variety of energy-storage applications, for example, high-performance fuel cells.

The local transport characteristics and the global polarization curve for a self-made micro proton exchange membrane fuel cell (PEMFC) have been experimentally and numerically investigated in this paper. The micro-sensors are developed to measure the local fluid temperature, cell voltage, and current density and the fuel cell test system is used to measure the polarization curve. A three-dimensional (3-D) non-isothermal compressible computational fluid dynamics (CFD) full-cell model is also adopted to simulate the test micro PEMFC. This CFD model has been validated with these global and local data. The ionic conductivity is increased as the water content in the membrane increases, enhancing the cell performance. This positive effect of inlet fuel humidity on the cell performance is also captured by the CFD simulation model.

The microwave-assisted polyol (MP) reduction was used as the deposition technique for preparing binary Pt–Sn alloys with a mean size of 5 nm on carbon nanotubes (CNTs). A large number of CNTs with an average diameter of 40–50 nm were attached to carbon paper substrate using a catalytic chemical vapor deposition. The fast MP synthesis enabled the formation of Pt–Sn nanoalloys within 6 min. X-ray diffraction and X-ray photoelectron spectroscopy were applied to analyze the crystalline alloy structure. Postcalcination at 600 °C showed a positive effect in improving the activity and the long-term durability (i.e., 1000 cycles) of Pt–Sn catalysts toward the H2SO4 electrolyte, as demonstrated by cyclic voltammetry test and AC impedance spectroscopy. An equivalent circuit also was proposed to analyze the equivalent serial resistance of the electrocatalysts after the potential cycling. This improvement can be attributed to the reasons that the calcination process is prone to the following: (i) the reinforcement of the adherence between the catalyst particle and the carbon support, (ii) the transformation of crystalline phase on Pt–Sn alloy, and (iii) the decrease of Pt (II) content and chemisorbed oxygen species. The Pt–Sn crystallographic phase on the CNT-based support shows an enhanced activity and more corrosion resistance in acidic electrolyte.

Bimetallic Pt–Zn catalysts with high and stable electrochemical activity towards sulfuric acid and methanol oxidation were synthesized by microwave-assisted polyol (MP) method. A catalytic chemical vapor deposition was used to directly grow multi-layered carbon nanotubes (CNTs) on carbon paper substrate. The as-grown CNT forest serves as a support for the Pt–Zn catalysts having a mean size of 3–5 nm. The catalytic activities of the supported Pt–Zn catalysts toward acid electrolyte and methanol oxidation were examined by cyclic voltammetry test with potential cycling. Experimental results confirmed that two-stage MP synthesis enables the improvement of electrochemical activity, antipoisoning ability and long-term durability of the binary catalyst. This improvement can be attributed to the bifunctional mechanism of the binary catalysts: the Zn content serves as a promoting center for the generation of Zn–OH species, and more Pt sites are thus available for methanol oxidation. Accordingly, the Pt–Zn/CNT catalyst, prepared by the MP approach, displays a potential candidate for fuel cell application due to its easy fabrication (6 min), low cost and no additional reduction process.

This article reports a facile microwave-assisted approach to synthesize Pt catalysts on carbon nanotube (CNT)/carbon paper (CP) composite through catalytic chemical vapor deposition. The Pt deposits, with an average size of 3–5 nm were uniformly coated over the surface of oxidized CNTs. The electrochemical activity and stability of the Pt–CNT/CP electrode were investigated in 1 M H2SO4 using cyclic voltammetry (CV) and ac electrochemical impedance spectroscopy. The Pt catalysts showed not only fairly good electrochemical activity (electrochemically active surface area) but also durability after a potential cycling of >1000 cycles. The analysis of ac impedance spectra associated with equivalent circuit revealed that the presence of CNTs significantly reduced both connect and charge transfer resistances, leading to a low equivalent series resistance ˜0.22 Ω. With the aid of CNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway. Thus, the CNTs do not only serve as carbon support, they also charge transfer media between the Pt catalysts and the gas diffusion layer. The results shed some light on the use of CNT/CP composite, offering a promising tool for evaluating high-performance gas diffusion electrodes.