The twinned Pd nanocatalyst exhibits sustainable NRR electrocatalytic performance by promoting the desorption of NH3

As ammonia is an important chemical raw material, a lot of efforts have been made in the field of electrochemical nitrogen reduction (NRR) to promote artificial nitrogen fixation. At present, NRR is widely focused on how to improve the catalyst\u0027s adsorption and activation of N2. However, it has not yet been studied how to promote the desorption of NH3 by the catalyst to obtain continuous and stable catalytic activity. Herein, we synthesized Pd octahedrons and icosahedrons with similar dimensions to study the effect of twin in NRR. At -0.2 V, the Pd icosahedron achieved the high NH3 yield and FE, respectively 17.56 μg h-1 cm-2 (43.9 μg h-1 mgcat.-1) and 31.98 %. After 200 h of electrolysis, the NH3 yield of Pd icosahedron did not significantly decrease, which maintained excellent catalytic stability. In-situ FTIR measurements and DFT calculation studies have proved that the existence of the twin crystal structure makes the center of the d-band of the catalyst slightly deviate from the Fermi level, which greatly reduces the reaction energy barrier of the NH3 desorption step and makes the catalyst maintain continuous excellent catalytic activity. This provides a new direction for improving the performance of NRR catalysts.