Electrocatalytic ammonia synthesis on Fe@MXene catalyst as cathode of intermediate-temperature proton-conducting solid oxide cell

Abstract

As the only carbon-free energy carrier without CO2 emission upon decomposition, ammonia is an ideal storage medium for H2. However, the current low efficiency of ammonia synthesis is a main challenge on intermediate-temperature proton-conducting electrochemical cells. Herein, we develop a novel non-precious cathode catalyst consisting of Fe nanoparticles loaded on two-dimensional MXene nanosheets (Fe@MXene) that can achieve a high Faradaic efficiency of 8.4% and an NH3 yield of 8.24 × 10−9 mol. s−1·cm−2 on an anode-supported Ba0·95Ce0·6Tb0·1Y0·2Zr0·1O3-δ-based electrolyte. The resultant catalyst with high specific surface area and catalytic active sites is beneficial to N2 reduction, resulting from the effective activation of N2 molecules imposed by the transported protons. The mechanism of catalytic NRR reveals that Fe@MXene catalyst can increase the electrocatalytic efficiency because of the improvement in the reaction rate constant. These show a promising catalyst of Fe@MXene for N2 reduction reaction using intermediate-temperature proton-conducting solid oxide cell.