西北工业大学李家源团队报道了利用可逆氢受体–供体实现硝酸盐到氨电催化的中继机制。相关研究成果发表在2024年10月21日出版的《德国应用化学》。

电催化硝酸盐还原是可持续氨生产的关键过程。然而，为了最大限度地提高氨的收率效率，该技术不可避免地在比0 V vs.RHE更负的电势下运行，导致高能耗和竞争性的氢气释放。

为了消除这一问题，作为可逆氢供体-受体的氢钨青铜（HxWO₃）与铜（Cu）结合，在0 V vs.RHE正电位下实现中继机制，这包括H快速嵌入HxWO₃晶格，晶格H迅速脱层并转移到Cu上，以及Cu上自发的H介导的硝酸盐到氨的转化。

所得催化剂具有3332.9±34.1 mmol gcat^-1 h^-1的高氨收率，在0.10 V vs. RHE时法拉第效率约为100%，显示出17.6 kWh kg氨^-1的创纪录的低估计能耗。使用这些催化剂，研究人员在一个扩大的流动池中实现了连续的氨生产，实际能耗为17.0 kWh kg氨^-1。

附：英文原文

Title: Reversible Hydrogen Acceptor–Donor Enables Relay Mechanism for Nitrate-to-Ammonia Electrocatalysis

Author: Yuefei Li, Ye Liu, Mingkai Zhang, Linsen Li, Zhao Jiang, Bingying Han, Baojun Wang, Jiayuan Li

Issue&Volume: 2024-10-21

Abstract: Electrocatalytic nitrate reduction is a crucial process for sustainable ammonia production. However, to maximize ammonia yield efficiency, this technology inevitably operates at the potentials more negative than 0 V vs. RHE, leading to high energy consumption and competitive hydrogen evolution. To eradicate this issue, hydrogen tungsten bronze (HxWO3) as reversible hydrogen donor-acceptor is partnered with copper (Cu) to enable a relay mechanism at potentials positive than 0 V vs. RHE, which involves rapid intercalation of H into HxWO3 lattice, prompt de-intercalation of the lattice H and transfer onto Cu, and spontaneous H-mediated nitrate-to-ammonia conversion on Cu. The resulting catalysts demonstrated a high ammonia yield rate of 3332.9±34.1 mmol gcat1 h1 and a Faraday efficiency of ~100 % at 0.10 V vs. RHE, displaying a record-low estimated energy consumption of 17.6 kWh kgammonia1. Using these catalysts, we achieve continuous ammonia production in an enlarged flow cell at a real energy consumption of 17.0 kWh kgammonia1.

DOI: 10.1002/anie.202417631

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202417631