Xiujuan Sun

High‐Performance Oxygen Reduction Electrocatalysts based on Cheap Carbon Black, Nitrogen, and Trace Iron

A real optimal Fe content: For N and Fe co-doped carbon electrocatalysts for oxygen reduction reactions (ORRs) it is found that there is a real optimal trace Fe content (Peak II), which has never been observed before. The real optimal electrocatalyst shows superior high activity for ORR and possesses the best price/performance ratio ever.

A Class of High Performance Metal-Free Oxygen Reduction Electrocatalysts based on Cheap Carbon Blacks

For the goal of practical industrial development of fuel cells, cheap, sustainable and high performance electrocatalysts for oxygen reduction reactions (ORR) which rival those based on platinum (Pt) and other rare materials are highly desirable. In this work, we report a class of cheap and high-performance metal-free oxygen reduction electrocatalysts obtained by co-doping carbon blacks with nitrogen and fluorine (CB-NF).The CB-NF electrocatalysts are highly active and exhibit long-term operation stability and tolerance to poisons during oxygen reduction process in alkaline medium. The alkaline direct methanol fuel cell with the best CB-NF as cathode (3 mg/cm2) outperforms the one with commercial platinum-based cathode (3 mg Pt/cm2). To the best of our knowledge, these are among the most efficient non-Pt based electrocatalysts. Since carbon blacks are 10,000 times cheaper than Pt, these CB-NF electrocatalysts possess the best price/performance ratio for ORR, and are the most promising alternatives to Pt-based ones to date.

Theoretical Study of Resorufin Reduction Mechanism by NaBH4

In the current work, the whole reduction mechanism of resorufin by sodium borohydride (NaBH4) has been investigated completely using quantum chemical theory for the first time. The possible pathways for each step were considered as much as possible. The calculated results reveal that the reduction mechanism for resorufin undergoes a nucleophilic addition with BH4(-), a synchronous proton abstraction from a carbon (C) atom, a protonation in a nitrogen (N) atom, and then a final hydrolysis process to obtain final reduced product dihydroresorufin. Interestingly, it was found that the protonation of N atom could induce a reduced product molecule with a Λ-type structure rather than a planar one, and the large alteration in geometry will induce different optical properties, such as fluorescent or nonfluorescent. More importantly, countercation Na(+) and solvation effect of H2O play important roles in reducing the activation energy in elementary steps, and their stabilization effect has been confirmed by NBO analysis. The detailed theoretical investigation for the reduction reaction of resorufin by NaBH4 will support some guidance for the similar reduction reaction for organic compounds like aldehydes and ketones.

Electrocatalysts and Catalyst Layers for Oxygen Reduction Reaction

Abstract In this chapter, to give some basic knowledge and concepts, some fundamentals about the catalyst activity and stability of oxygen reduction reaction (ORR) electrocatalysts, which are the targeted research systems by rotating electrode methods, are presented. A detailed description about the electrocatalysts and catalyst layers and their applications for ORR in terms of their types, structures, properties, catalytic activity/stability, as well as their research progress in the past several decades are also given. Furthermore, both the synthesis and characterization methods for ORR electrocatalysts, and the fabrication procedures for catalyst layers are also reviewed.