Hierarchical hollow nanotubes of NiFeV-layered double hydroxides@CoVP heterostructures towards efficient, pH-universal electrocatalytical nitrogen reduction reaction to ammonia.

• Novel hollow hierarchical nanotubes (HHNTs) of CoVP@NiFeV-layered double hydroxides heterostructure is synthesized. • Hierarchical hollow nanotubes micro/nanostructures increase the electrochemical active surface area and active sites. • The strong chemical interaction between NiFeV-LDHs and CoVP plays a key role in the electrochemical activities. • The HHNTs heterostructures show great catalytic activity towards high Faradaic efficiency, pH-universal NRR to NH 3 synthesis. Electrocatalytical nitrogen reduction reaction (NRR) under ambient conditions provides a promising substitute to the typical Haber−Bosch process that involves high energy and greenhouse gases emission. Herein, we develop non-noble metal based hollow hierarchical nanotubes (HHNTs) of CoVP@NiFeV-layered double hydroxides (LDHs) heterostructures as a high-performance electrocatalyst for NRR, in which the novel 3D hollow hierarchical structure provides highly rich surface active sites for the adsorption and reduction of nitrogen to NH 3. Electrochemical measurements for NRR reveal high activity (NH 3 rate: 1.6 × 10−6 mol h−1 cm−2), high Faradaic efficiency (13.8%) and excellent selectivity at −0.3 V versus reversible hydrogen electrode (RHE), outperforming other noble metals catalysts for N 2 fixation and most of state-of-the-art metal-free NRR electrocatalysts. Furthermore, CoVP@NiFeV-LDHs HHNTs could maintain high selectivity and durability over repeated reaction cycles. Therefore, this work highlights the first example of CoVP@NiFeV-LDHs hierarchical micro/nanostructures, which serve as electrocatalysts towards high-efficiency, pH-universal NRR to ammonia synthesis. [ABSTRACT FROM AUTHOR]