Engineering oxygen vacancies in Co3O4 to boost p-d hybridization for hydrogeneration of nitrogen and oxygen

Electrochemical hydrogenerations of nitrogen and oxygen molecules are of significance for nitrogen reduction and oxygen reduction reactions. Strengthening the binding between active sites and gaseous molecules is beneficial for enhancing the catalytic performance, especially in NRR catalysis. In this work, we have engineered the oxygen vacancies in Co 3 O 4 nanoparticles to boost the catalytic activity towards NRR and ORR. Ascribing to the p-d hybridization between Co and N atoms, N 2 electrochemical adsorption is promoted and the related energy barrier of N 2 protonation is significantly decreased by 50%; as a consequence, Faradaic efficiency is 11.2% at −0.4 V vs. RHE, 3-fold higher than Co 3 O 4 /CNT; moreover, due to the oxygen vacancies in Co 3 O 4-x /CNT leading to a higher oxophilicity, Co 3 O 4-x /CNT showed a better selectivity in ORR catalysis and kinetic current density at 0.85 V vs. RHE is boosted by 2.4 times. Consequently, Co 3 O 4-x /CNT exhibits a better rechargeable zinc air battery performance than Pt/C-IrO 2 by a factor of 2.2.