Tuning the performance of Fe-porphyrin aerogel-based PGM-free oxygen reduction reaction catalysts in proton exchange membrane fuel cells.

Fe-N-C catalysts are currently the leading candidates to replace Pt-based catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells. To maximize their activity, it is necessary to optimize their structure to allow high active site density on one hand, and hierarchical porous structure that will allow good mass transport of reactants and products to and from the active sites on the other hand. Hence, the hierarchical structure of the catalyst plays an important role in the balance between the electrochemical active site density and the mass transport resistance.

NiFe-mixed metal porphyrin aerogels as oxygen evolution reaction catalysts in alkaline electrolysers.

Aerogels are a very interesting group of materials owing to their unique physical and chemical properties. In the context of electrocatalysis, the focus has been on their physical properties, and they have been used primarily as catalyst supports so far. In this work, we synthesized porphyrin aerogels containing Ni and NiFe mixed metal materials and studied them as catalysts for the oxygen evolution reaction (OER).

Application of Molecular Catalysts for the Oxygen Reduction Reaction in Alkaline Fuel Cells.

The development of precious group metal-free (PGM-free) catalysts for the oxygen reduction reaction is considered as the main thrust for the cost reduction of fuel cell technologies and their mass production. Within the PGM-free category, molecular catalysts offer an advantage over other heat-treated PGM-free catalysts owing to their well-defined structure, which enables further design of more active, selective, and durable catalysts. Even though non-heat-treated molecular catalysts with exceptional performance have been reported in the past, they were rarely tested in a fuel cell.

Bifunctional PGM-free metal organic framework-based electrocatalysts for alkaline electrolyzers: trends in the activity with different metal centers.

In order to solely rely on renewable and efficient energy sources, reliable energy storage and production systems are required. Hydrogen is considered an ideal solution as it can be produced electrochemically by water electrolysis and renewably while no pollutants are released when consumed. The most common catalysts in electrolyzers are composed of rare and expensive precious group metals.

Enhancement of the oxygen reduction reaction electrocatalytic activity of metallo-corroles using contracted cobalt(iii) CF-corrole incorporated in a high surface area carbon support.

Molecular oxygen reduction reaction catalysts based on metallo-corrole with the smallest meso-substituent reported to-date, Co(iii)CF-corrole, was synthesized and compared to the well-studied Co(iii)tpfcorrole when adsorbed on a high surface area carbon support. This study shows the improved electrocatalytic performance with the new corrole, attributed to its unique compact structure, which enables surface interactions in favor of lowering the reaction overpotential by 70 mV.

Heat-Treated Aerogel as a Catalyst for the Oxygen Reduction Reaction.

Aerogels are fascinating materials that can be used for a wide range of applications, one of which is electrocatalysis of the important oxygen reduction reaction. In their inorganic form, aerogels can have ultrahigh catalytic site density, high surface area, and tunable physical properties and chemical structures-important features in heterogeneous catalysis. Herein, we report on the synthesis and electrocatalytic properties of an iron-porphyrin aerogel.

Bioinspired Electrocatalysis of Oxygen Reduction Reaction in Fuel Cells Using Molecular Catalysts.

One of the most important chemical reactions for renewable energy technologies such as fuel cells and metal-air batteries today is oxygen reduction. Due to the relatively sluggish reaction kinetics, catalysts are necessary to generate high power output. The most common catalyst for this reaction is platinum, but its scarcity and derived high price have raised the search for abundant nonprecious metal catalysts.