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As well known, ruthenium is electrochemically unstable in direct methanol fuel cell (DMFC) operation shortening lifetime and deteriorating performance of DMFC device. In this work, a facile methodology for improvement in stability of PtRu electrocatalyst is described, in which PtRu alloyed nanoparticles are decorated by nitrogen-doped carbon (N x C) originating from the carburization of in-situ polymerized polyaniline (PANI). Deceleration in Ru dissolution of N x C protected PtRu electrocatalyst comes from the ionized Ru atoms induced by the carburization of PANI transferring electrons from Ru to nitrogen atoms evidenced by XPS measurement, which results in higher CO tolerance during potential sweeping from 0.6 to 1.0 V versus RHE for N x C decorated PtRu electrocatalyst. Meanwhile, N x C protected PtRu electrocatalyst only losses 10% of active sites after stability estimation; in contrast, 50% of active sites are lost for bare PtRu electrocatalyst. Moreover, fuel cell test illustrates that N x C protected PtRu electrocatalyst shows comparable performance to bare PtRu electrocatalyst. [ABSTRACT FROM AUTHOR]

Enhancement in durability of electrocatalyst is still one of the most important issues in polymer electrolyte fuel cells (PEFCs). Here, we report a structurally coated electrocatalyst supported on carbon nanotubes (CNT), in which platinum (Pt) nanoparticles are coated by nitrogen doped carbon (NC) layers. CNT/NC/Pt/NC shows comparable electrochemical surface area (ECSA) and oxygen reduction reaction (ORR) activity to the non-coated electrocatalyst (CNT/NC/Pt), indicating that NC layer on Pt nanoparticles almost negligibly affects the activities of electrocatalyst; while, CNT/NC/Pt/NC exhibits a higher Pt stability due to the unique structure, in which the Pt nanoparticles are stabilized by the NC layers and Pt aggregation is decelerated proved by TEM measurement. Maximum power density of CNT/NC/Pt/NC reached 604 mW cm −2 with Pt loading of 0.1 mg Pt cm −2 , which only decreases by 7% compared to CNT/NC/Pt (650 mW cm −2 ). The electrochemical analysis and fuel cell test illustrate that NC layer on Pt nanoparticles enhances the durability without serious deterioration of fuel cell performance. [ABSTRACT FROM AUTHOR]

In this work, we focus on the durability, CO tolerance and sluggish methanol oxidation reaction (MOR) of PtRu electrocatalyst. Here, we fabricate a new PtRu electrocatalyst supported on carbon black (CB), in which the PtRu nanoparticles are structurally sandwiched by poly(vinyl pyrrolidone) (PVP) and poly(2,5-benzimidazole) (ABPBI). Due to the first coating (PVP) on CB, the micropores on CB are capped resulting in high Pt utilization efficiency (94%) and catalytic activity toward methanol oxidation. Meanwhile, the second coating (ABPBI) on PtRu nanoparticles fabricated via in-situ polymerization improves the PtRu stability and decelerates the Ru dissolution leading to stable electrochemical surface area (ECSA), MOR activity and CO tolerance during the durability test. Without ABPBI coating, ECSA and catalytic activity remain only 50% after potential cycling. Additionally, the fuel cell performance of double polymer coated electrocatalyst reaches 103 mW cm −2 , which is among the highest values reported in the recent literatures. [ABSTRACT FROM AUTHOR]

The high dimensional swelling has been considered as one of the most important issues for obstructing sulfonated poly (ether ether ketone) (SPEEK) membrane with high IEC value as an excellent performance proton exchange membrane (PEM) for direct methanol fuel cell (DMFC) application. Here, we present a facile way to overcome the issue via blending the fully aromatic polyamide ( fa -PA) into SPEEK membrane. The Influence of the fa -PA on the key properties of the fabricated fa -PA/SPEEK composite membranes ( fa -PASPs) was systematically investigated. As the promising dimensional stability of the fa -PA, the fa -PASPs display excellent dimensional stability both in water and methanol aqueous solution. In addition, the fa -PASPs exhibit uniform and smooth morphology due to the same fully aromatic polyamide backbones as SPEEK and strong hydrogen bonding interactions between fa -PA and SPEEK with significantly reduced methanol crossover. The remarkable cell performance at high methanol concentration up to neat methanol was significantly obtained, suggesting that the prepared fa -PASPs are suitable for using as PEMs in direct methanol fuel cells application. [ABSTRACT FROM AUTHOR]