论文部分内容阅读
Achieving more meaningful -N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of -N2 fixation instead of the Haber–Bosch process. Unfortu-nately, the electrochemical -N2 reduction reaction (NRR) method as a rising approach currently still shows low selectivity (Faradaic effciency?10%) and high-energy consumption [applied potential at least ??0.2 V versus the reversible hydrogen electrode (RHE)]. Here, the role of molybdenum alu-minum boride single crystals, belonging to a family of ternary transition metal aluminum borides known as MAB phases, is reported for the electro- chemical NRR for the first time, at a low applied potential (??0.05 V versus RHE) under ambient conditions and in alkaline media. Due to the unique nano-laminated crystal structure of the MAB phase, these inexpensive materials have been found to exhibit excellent electrocatalytic performances -(NH3 yield: 9.2 μg h?1 cm?2 mg?1cat., Faradaic effciency: 30.1%) at the low overpotential, and to display a high chemical stability and sustained catalytic performance. In conjunction, further mechanism studies indicate B and Al as main-group metals show a highly selective affnity to -N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals, while Mo exhibits specific catalytic activity toward the subsequent reduction reaction. Overall, the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reac-tion and achieve enhanced NRR performance. The significance of this work is to provide a promising candidate in the future synthesis of ammonia.