Abstract:In order to reduce the overall system cost, the development of inexpensive, high-performance and durable oxygen reduction reaction (ORR)N, Fe-codoped carbon-based (Fe/N/C) electrocatalysts to replace currently used Pt-based catalysts has become one of the major topics in research on fuel cells. This review paper lays the emphasis on introducing the progress made over the recent five years with a detailed discussion of recent work in the area of Fe/N/C electrocatalysts for ORR and the possible Fe-based active sites. Fe-based materials prepared by simple pyrolysis of transition metal salt, carbon support, and nitrogen-rich small molecule or polymeric compound are mainly reviewed due to their low cost, high performance, long stability and because they are the most promising for replacing currently used Pt-based catalysts in the progress of fuel cell commercialization. Additionally, Fe-base catalysts with small amount of Fe or new structure of Fe/Fe3C encased in carbon layers are presented to analyze the effect of loading and existence form of Fe on the ORR catalytic activity in Fe-base catalyst. The proposed catalytically Fe-centered active sites and reaction mechanisms from various authors are also discussed in detail, which may be useful for the rational design of high-performance, inexpensive, and practical Fe-base ORR catalysts in future development of fuel cells. OPEN ACCESSCatalysts 2015, 5 1168

Herein, a type of Fe, N-codoped carbon electrocatalyst (FeN /C, Fe-N-BCNT#BP) containing bamboo carbon nanotubes and displaying bifunctional high catalytic efficiency for both oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR) is reported. It shows high electrocatalytic activity and stability for both the ORR process with onset potential of 1.03 V in alkaline and the CO2RR to CO with high faradic efficiency up to 90% and selectivity of about 100% at low overpotential of 0.49 V. For CO2RR to CO, it is revealed that Fe C is active but the activity of FeN centers is lower than that of C-N-based centers, contrary with that observed for ORR. Due to its low cost and high electrocatalytic performance for these two reduction reactions, the obtained catalyst is very promising for extensive application in future. The revealed huge activity difference of the same types of active sites for different reactions can efficiently guide the synthesis of advanced materials with multifunction.

In the present work, we proposed an effective method to regenerate sintered gold catalyst by improving the dispersion of gold nanoparticles. With the liquid oxychlorination reaction, a sintered carbon-supported gold (Au/C) nanocatalyst was effectively regenerated by improving the redispersion of Au nanoparticles with additional carbon support. The Au-catalyzed model reaction between 4-nitrophenol and sodium borohydride (NaBH 4 ) indicates that the apparent activity of the optimal Au/C regenerated (Au 0.45 wt %) exceeds that of the initial fresh Au/C (Au 1 wt %), making Au utilization tripled and potentially sustainable for their extensive application in industry.

An ultrahigh pressure (UHP) method was employed to rapidly synthesize (5 min) a high-efficiency ORR FeNx/C catalyst for the first time.