Pt NPs Supported on CeO/C as Electrocatalysts for Oxygen Reduction Reaction: Novel Physicochemical Insights on the Synthesis and on the Improved Activity and Stability.

This study emphasizes the effect of CeO on the Pt nanoparticle (NP) dimension, stability, and activity versus the oxygen reduction reaction. It is demonstrated that the one-pot synthesis of Pt NPs along with CeO NPs over carbon support produces small Pt NPs (2 nm) with higher activity, than the sole Pt NPs, thanks to the cooperative interaction exerted by CeO. This is nicely demonstrated by using synchrotron wide-angle X-ray total scattering and advanced data analysis, monitoring the in situ nucleation and growth of Pt NPs in the presence of preformed CeO NPs or of a Ce precursor.

Establishing the stability number descriptor for Fe-N-C fuel cell electrocatalysts.

Fe-N-C electrocatalysts demonstrate high potential in catalyzing oxygen reduction reaction (ORR) in polymer electrolyte fuel cells, yet the bottleneck for their application is their moderate stabilities. In our previous work, we discovered a linear correlation between the rates of ORR and Fe dissolution in alkaline media at room temperature, and the stability (-) number descriptor that reflects this correlation was introduced. On the way toward further generalization and establishment of this descriptor, we investigate the effect of pH, potential, current density, and temperature on the dissolution behavior of various representative Fe-N-C electrocatalysts.

Boosting the O-to-HO Selectivity Using Sn-Doped Carbon Electrocatalysts: Towards Highly Efficient Cathodes for Actual Water Decontamination.

The high cost and often complex synthesis procedure of new highly selective electrocatalysts (particularly those based on noble metals) for HO production are daunting obstacles to penetration of this technology into the wastewater treatment market. In this work, a simple direct thermal method has been employed to synthesize Sn-doped carbon electrocatalysts, which showed an electron transfer number of 2.04 and outstanding two-electron oxygen reduction reaction (ORR) selectivity of up to 98.

Synergistic Effect of Sn and Fe in Fe-N Site Formation and Activity in Fe-N-C Catalyst for ORR.

Iron-nitrogen-carbon (Fe-N-C) materials emerged as one of the best non-platinum group material (non-PGM) alternatives to Pt/C catalysts for the electrochemical reduction of O in fuel cells. Co-doping with a secondary metal center is a possible choice to further enhance the activity toward oxygen reduction reaction (ORR). Here, classical Fe-N-C materials were co-doped with Sn as a secondary metal center.

Sulfur Doping versus Hierarchical Pore Structure: The Dominating Effect on the Fe-N-C Site Density, Activity, and Selectivity in Oxygen Reduction Reaction Electrocatalysis.

Nitrogen doping has been always regarded as one of the major factors responsible for the increased catalytic activity of Fe-N-C catalysts in the oxygen reduction reaction, and recently, sulfur has emerged as a co-doping element capable of increasing the catalytic activity even more because of electronic effects, which modify the d-band center of the Fe-N-C catalysts or because of its capability to increase the Fe-N site density (SD). Herein, we investigate in detail the effect of sulfur doping of carbon support on the Fe-N site formation and on the textural properties (micro- and mesopore surface area and volume) in the resulting Fe-N-C catalysts. The Fe-N-C catalysts were prepared from mesoporous carbon with tunable sulfur doping (0-16 wt %), which was achieved by the modulation of the relative amount of sucrose/dibenzothiophene precursors.