Sustainable Nitrogen Fixation to Produce Ammonia by Electroreduction of Plasma-Generated Nitrite
Wenyi Li, Shengbo Zhang, Jun Ding, Jun Ding, Jiafang Liu, Zhiwei Wang, Haimin Zhang, Jun Ding, Jun Ding, Longwei Chen, Changhao Liang
Abstract
One-step electrocatalytic N 2 fixation is of emerging interest but is retarded due to the tough dissociation of the N 2 triple bond and low NH 3 selectivity. Here, a plasma-electrocatalytic integrated strategy is reported to be effective to circumvent this dilemma and realize high-performance N 2 fixation via decoupling the reaction to two steps with NO x – serving as an intermediary: (i) non-thermal plasma (NTP) drives air activation into highly active NO x – intermediates, and (ii) subsequent electroreduction of the resultant NO x – into NH 3 . A gliding arc–microwave conjunction plasma mode was found to be preferred to achieve an optimal NO 2 – -N concentration of 2844.31 μg mL –1, adopting 0.5 M KOH as the absorption solution in the first step. For the next ENO 2 – RR step, plasma-treated 0.5 M KOH was directly used as electrolyte, with well-designed Cu 2 Pd nanodots anchored on carbonized bacterial cellulose (Cu 2 Pd/CBC) as electrocatalyst. An exceptional ENO 2 – RR performance, including a superior R NH 3 of 1956.65 μg h –1 mg –1, highest FE of 93.79%, and long time stability of 30 h, was attained for Cu 2 Pd/CBC, outperforming the counterparts Cu/CBC and Pd/CBC. The synergism of CuPd bifunctional catalytic sites is the key to the greatly enhanced electrocatalytic activity via improving the adsorption of NO 2 – and the related intermediates while simultaneously supplying sufficient protons. This work provides an alternative strategy toward sustainable and distributed on-site ammonia synthesis.