Impact of carbon and nitrogen doping on trimetallic iron–nickel–cobalt aerogels as electrocatalysts for enhanced urea oxidation: A strategy for energy-efficient hydrogen production

The replacement of the oxygen evolution reaction (OER) with alternative anodic processes offers an attractive approach to reduce energy demand of electrochemical cells. The urea oxidation reaction (UOR) was investigated in a microfluidic electrochemical cell as a substitute for OER. Iron-nickel-cobalt aerogels (FeNiCoA), doped with carbon (C-FeNiCoA) and nitrogen (N-FeNiCoA), were synthesized and tested as anode catalysts. N-FeNiCoA achieved low onset potential of 0.63 V and 33.3 mA cm −2 at 1.42 V, highlighting significant energy savings compared to conventional OER systems. Optimization of the microfluidic conditions demonstrated that a 1 M CO(NH 2 ) 2 : 1 M KOH electrolyte maximizes electrocatalytic flux while minimizing parasitic reactions. The integration of an internal Ag/AgCl reference electrode enabled accurate separation of anodic and cathodic overpotentials. This validation confirmed that the total cell current matched the sum of the independent half-cell responses, demonstrating the high efficiency and reliability of N-FeNiCoA in integrated microfluidic platforms. • Fast microwave-assisted synthesis produces uniform porous FeNiCoA aerogels. • N-doping significantly enhances electron transfer and UOR catalytic activity. • N-FeNiCoA reaches 33.3 mA cm −2 at 1.42 V and 0.63 V onset potential for UOR. • Cell modification with a reference electrode allows for an independent anode-cathode study. • Low-cost FeNiCoA aerogels are efficient alternatives to noble metal catalysts.