Enabled Efficient Ammonia Synthesis and Energy Supply in a Zinc–Nitrate Battery System by Separating Nitrate Reduction Process into Two Stages
Haifeng Jiang, Gao‐Feng Chen, Aleksandr Savateev, Jian Xue, Liang‐Xin Ding, Zhenxing Liang, Markus Antonietti, Haihui Wang
Abstract
Abstract The aqueous electrocatalytic reduction of NO 3 − into NH 3 (NitrRR) presents a sustainable route applicable to NH 3 production and potentially energy storage. However, the NitrRR involves a directly eight‐electron transfer process generally required a large overpotential (<−0.2 V versus reversible hydrogen electrode ( vs . RHE)) to reach optimal efficiency. Here, inspired by biological nitrate respiration, the NitrRR was separated into two stages along a [2+6]‐electron pathway to alleviate the kinetic barrier. The system employed a Cu nanowire catalyst produces NO 2 − and NH 3 with current efficiencies of 91.5 % and 100 %, respectively at lower overpotentials (>+0.1 vs . RHE). The high efficiency for such a reduction process was further explored in a zinc‐nitrate battery. This battery could be specified by a high output voltage of 0.70 V, an average energy density of 566.7 Wh L −1 at 10 mA cm −2 and a power density of 14.1 mW cm −2 , which is well beyond all previously reported similar concepts.