A Cascade Jet Plasma Oxidation─electroreduction System Using Pd‐Ni Dual‐Site Catalyst for Sustainable Ammonia Production from Air
Jun Ding, Wenyi Li, Heng Zhang, Heng Zhang, Shu Tang, Zhixian Mao, Shengbo Zhang, Meng Jin, Qifu Lin, Yunxia Zhang, Guozhong Wang, Haimin Zhang, Haimin Zhang
Abstract
Abstract Electrocatalytic N 2 reduction reaction (eNRR) has been deemed as an alternative approach to the Haber‐Bosch (H‐B) process for ammonia (NH 3 ) production, but it remains a huge challenge. Here jet plasma oxidation of N 2 is reported in air into NO x and subsequently NO 2 − coupling with electrochemical NO 2 − reduction reaction (pN 2 ─eNO 2 − RR) over PdNi alloying nanoparticles on N‐doped carbon nanotubes (PdNi/N‐CNTs) for NH 3 synthesis. The results demonstrate that the jet plasma reactor possesses excellent gas reforming capacity to achieve the largest NO 2 − yield rate of 30.46 mmol h −1 with a low energy consumption of 2.66 kWh mol N −1 . For subsequent eNO 2 − RR, PdNi/N‐CNTs can afford an NH 3 yield of 34.96 mg h −1 mg cat. −1 and a faradaic efficiency (FE) of 98.21% at −0.38 and 0.02 V (vs RHE), respectively. In situ spectroscopic characterizations combined with theoretical calculations unveil that PdNi/N‐CNTs provide Pd and Ni dual active sites, enabling NO 2 − activation on the Ni site and active H * provision on the Pd site to facilitate eNO 2 − RR. A cascade pN 2 ‐eNO 2 − RR system is constructed for sustainable NH 3 production, achieving a stable NH 3 yield rate of 25.56 mmol h −1 , an average FE >85%, as well as NO x to NH 3 conversion efficiency of 44.62% at constant ampere‐level current with finally collection of gram‐level (NH 4 ) 2 SO 4 product.