A Synergistic Hybrid of Sr3B2O6‐SryTi0.6Fe0.4O3‐δ (y < 1) as a Cathode for High‐Performance Electrochemical Ammonia Synthesis via Protonic Ceramic Electrolysis Cells

Abstract The electrochemical nitrogen reduction reaction (e‐NRR) presents a promising approach for environmentally friendly ammonia synthesis. However, the efficiency of ammonia synthesis can be hindered by competitive hydrogen evolution reactions (HER). Therefore, the development of a catalyst capable of suppressing HER is essential. In this study, a synergistic hybrid catalyst Sr(Ti 0.6 Fe 0.4 ) 0.8 B 0.2 O 3‐δ [S(TF)B 0.2 ], composed of Sr 3 B 2 O 6 (SB) and Sr y Ti 0.6 Fe 0.4 O 3‐δ (S y TF, y<1) is synthesized and used as an electrocatalyst for electrochemical ammonia synthesis via protonic ceramic electrolysis cells, in which SB is utilized as a proton acceptor, thereby inhibiting HER and promoting proton‐coupled electron transfer (PCET) for the ammonia synthesis. The formation of SB results in a deficiency of A‐site cations in S y TF, leading to an increased number of oxygen vacancies in S(TF)B 0.2 . DFT calculation indicates that oxygen vacancies facilitate ammonia generation and desorption, adhering to the enzymatic pathway for NH 3 synthesis. Additionally, the grain boundary (GB) between S y TF and SB introduces further defects, which contribute to the enhancement of the eNRR. Research indicates that utilizing S(TF)B 0.2 as a catalyst enhances both the ammonia synthesis rate and Faradaic efficiency. This study presents a straightforward and efficient approach for the fabrication of eNRR catalysts.