Promoted Two-Step Ammonia Synthesis with CoOOH/Co foam at Ampere-Level Current Density and Nearly 100% Faraday Efficiency from Air and Water

Ammonia (NH₃) is regarded as an essential hydrogen storage material in the new energy field, and plasma-electrocatalytic synthesis of NH₃ (PESA) is an alternative to the traditional Haber-Bosch process. Here, a bifunctional catalyst CoOOH/CF is proposed to enhance the PESA process. Benefiting from the efficient activation of O₂ by CoOOH/CF, NO_x ^- yield rate can reach the highest value of 171.90 mmol h^-1 to date. Additionally, CoOOH holds a more negative d-band center, thereby exhibiting weaker adsorption toward NO^*, lowering the energy barrier for the rate determining step, resulting in a high NH₃ yield rate (302.55 mg h^-1 cm^-2 at -0.8 V) with ampere-level NH₃ current density (2.86 A cm^-2 at -0.8 V) and nearly 100% Faraday efficiency (FE, 99.8% at -0.6 V). Moreover, CoOOH/CF achieves an excellent 4.54 g h^-1 NH₃ yield rate with 97.9% FE in an enlarged electrolyzer, demonstrating the feasibility of PESA on a large scale.