Interface Engineering of SRu-mC₃N₄ Heterostructures for Enhanced Electrochemical Hydrazine Oxidation Reactions

Hydrazine oxidation in single-atom catalysts (SACs) could exploit the efficiency of metal atom utilization, which is a substitution for noble metal-based electrolysers that results in reduced overall cost. A well-established ruthenium single atom over mesoporous carbon nitride (SRu-mC₃N₄) catalyst is explored for the electro-oxidation of hydrazine as one of the model reactions for direct fuel cell reactions. The electrochemical activity observed with linear sweep voltammetry (LSV) confirmed that SRu-mC₃N₄ shows an ultra-low onset potential of 0.88 V vs. RHE, and with a current density of 10 mA/cm² the observed potential was 1.19 V vs. RHE, compared with mesoporous carbon nitride (mC₃N₄) (1.77 V vs. RHE). Electrochemical impedance spectroscopy (EIS) and chronoamperometry (i-t) studies on SRu-mC₃N₄ show a smaller charge-transfer resistance (R_Ct) of 2950 Ω and long-term potential, as well as current stability of 50 h and 20 mA/cm², respectively. Herein, an efficient and enhanced activity toward HzOR was demonstrated on SRu-mC₃N₄ from its synergistic platform over highly porous C₃N₄, possessing large and independent active sites, and improving the subsequent large-scale reaction.