Nitrogen reduction reaction under ambient conditions by K3Ti8O17 nanorod electrocatalyst

Abstract

The substantial enhancement of ammonia consumption in diverse fields paved the way to establish electrochemical nitrogen reduction reaction (NRR) as one of the idyllic alternatives for the energy-intensive Haber process. Metal oxides are significantly recognized as efficient electrocatalysts for NRR since they can facilitate the activation of the N₂ triple bond. Herein, a new titanate-based mixed metal oxide, K₃Ti₈O₁₇, having a nanorod morphology was synthesized through a simple citrate-gel process at a lower calcination temperature as an electrocatalyst for NRR. The micrographs of K₃Ti₈O₁₇ show uniformly distributed one-dimensional rods with ∼120 nm length. Under ambient conditions, the obtained K₃Ti₈O₁₇ nanorods exhibited excellent activity towards NRR in an acidic medium with 31.6 μg h⁻¹ mg_cat⁻¹ NH₃ yield and 15% FE at −0.5 V versus the reversible hydrogen electrode in 0.1 M HCl. The presence of an alkali metal ion (K⁺) in the system provided the assistance for enhancement in NRR activity compared to that of pure TiO₂via activating the strong triple bond in molecular nitrogen. The K₃Ti₈O₁₇ catalyst showed consistent catalytic activity towards NRR during the stability study.