p-Block Metal Oxide as an Efficient Electrocatalyst for Boosting Ambient Ammonia Synthesis

The electrocatalytic nitrogen reduction reaction (NRR) offers a promising alternative to the traditional Haber–Bosch process for producing NH3 under ambient conditions. Designing efficient electrocatalysts is crucial for achieving an active and selective NRR, as these catalysts can lower the energy barrier and modify the rate-determining step. Catalysts featuring Lewis acid active centers are particularly effective for NRR due to their ability to facilitate N2 adsorption and subsequent reduction. Herein, we have chosen a p-block element (Al) as the active center due to its Lewis acidity and synthesized the material, zinc aluminate (ZnAl2O4, ZAO). Al–O can participate in bonding and antibonding interactions with N2 molecules and activates for the reduction. The ZAO electrocatalyst attained a Faradaic efficiency of 45.9% at −0.3 V versus the reversible hydrogen electrode (RHE) for selective NH3 production in a 0.1 M Na2SO4 electrolyte. Furthermore, in situ attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy confirmed the formation of intermediates during the NRR pathway. This research offers a new approach for designing efficient catalysts using p-block elements, enhancing the electrocatalytic NRR for ammonia synthesis.