Synergistic Catalytic Effect of Hollow Carbon Nanosphere and Silver Nanoparticles for Oxygen Reduction Reaction

Non-Noble Metal Catalysts in Cathodic Oxygen Reduction Reaction of Proton Exchange Membrane Fuel Cells: Recent Advances

The oxygen reduction reaction (ORR) is one of the crucial energy conversion reactions in proton exchange membrane fuel cells (PEMFCs). Low price and remarkable catalyst performance are very important for the cathode ORR of PEMFCs. Among the various explored ORR catalysts, non-noble metals (transition metal: Fe, Co, Mn, etc.) and N co-doped C (M-N-C) ORR catalysts have drawn increasing attention due to the abundance of these resources and their low price. In this paper, the recent advances of single-atom catalysts (SACs) and double-atom catalysts (DACs) in the cathode ORR of PEMFCs is reviewed systematically, with emphasis on the synthesis methods and ORR performance of the catalysts. Finally, challenges and prospects are provided for further advancing non-noble metal catalysts in PEMFCs.

Oxygen reduction on silver catalysts electrodeposited on various nanocarbon supports

In this work, Ag particles were electrodeposited onto nitrogen-doped graphene oxide, graphene, multi-walled carbon nanotube (MWCNT), and Vulcan carbon XC-72R supports by varying the upper potential limit. The surface morphology of the resulting Ag-based catalysts was examined by scanning electron microscopy. The electrochemical oxygen reduction reaction (ORR) was tested in alkaline media employing the rotating disk electrode method. The variation of the upper potential limit influenced the size of silver nanoparticles and their number density on the substrate surface. All the Ag-based electrocatalysts studied in this work showed remarkable ORR activity in terms of half-wave potentials. The ORR results combined with hydrogen peroxide reduction results prove that all Ag catalysts tested are suitable for both reactions. Ag/NGO2 catalyst possesses the highest mass activity for ORR, which indicates a relationship between the Ag loading and electrocatalytic activity. The electroreduction of oxygen on all the electrodeposited silver catalysts follows a four-electron pathway in alkaline environment. These materials are promising alternatives for Pt/C catalyst to be used as alkaline membrane fuel cell cathodes.

Investigation of ZIF-derived Co, N co-doped porous carbon-supported Au nanoparticles as an effective catalyst for borohydride electrooxidation

An Au/CoNPC nanoparticle composite electrocatalyst with lower cost and higher catalytic activity would be a promising anode for direct borohydride fuel cells.