Reinforced nitrogen fixation via synergistic Ru-Ni dual sites

Abstract

The electrocatalytic nitrogen reduction reaction (NRR) is challenging but crucial for the sustainable development of both industry and agriculture. To enhance NRR performance, it is critically important to construct advanced electrocatalysts that offer satisfactory performance containing high activity and selectivity. However, the strong affinity of nitrogen-containing species on the Ru surface resulted in suboptimal NRR activity. Herein, we propose a dual-site catalyst, RuNi, to optimize the binding strength, which leads to superior electrocatalytic performance, achieving a high NH₃ yield rate of 5.07 µg h^-1 cm^-2 at -0.2 V vs. RHE and a Faradaic efficiency (FE) of 26.2 % at -0.1 V vs. RHE in 0.1 mol/L Na₂SO₄. Owing to the synergistic interaction between Ru and Ni, a remarkable performance is realized over the RuNi catalyst. In-situ characterization evidenced that hydrogen radicals (H*) on the Ni site of the RuNi catalyst participate in the dissociation of N₂ adsorbed on the Ru site, and theoretical investigations indicated that RuNi reduces the adsorption strength of intermediates. This offers an effective approach to the synthesis of dual-site catalysts for electrocatalytic ammonia synthesis.