Low-overpotential electrochemical ammonia synthesis using BiOCl-modified 2D titanium carbide MXene

Electrochemical synthesis of ammonia has the advantages of low energy consumption and promising environmental protection, as compared to the traditional Haber-Bosch process. However, the commercial utilization of this novel system is limited by the low Faradaic efficiency, poor ammonia yield and high overpotential due to the strong N N bond and the dominant competing reaction of hydrogen evolution reaction (HER). Herein, a BiOCl-modified two-dimensional (2D) titanium carbide MXenes nanocomposite (BiOCl@Ti 3 C 2 T x ) is proposed as a promising electrocatalyst for ambient nitrogen (N 2 ) reduction reaction with excellent catalytic performance and superior long-term stability at low overpotential. In 0.1 mol/L HCl, this catalyst attains a high Faradic efficiency of 11.98% and a NH 3 yield of 4.06 µg h −1 cm −2 at −0.10 V ( vs. RHE), benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, combined with its large specific surface area and the facile electron transfer. A noble-metal free electrocatalytic system of BiOCl@Ti 3 C 2 T x has been fabricated via in-situ hydrothermal growth of BiOCl on the Ti 3 C 2 T x , showing significantly enhanced electrocatalytic nitrogen reduction reaction performance at low overpotential.