Wu Tongwei, Zhao Haitao, Zhu Xiaojuan, Xing Zhe, Liu Qian, Liu Tong, Gao Shuyan, Lu Siyu, Chen Guang, Asiri Abdullah M, Zhang Yanning, Sun Xuping
Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China.
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Adv Mater. 2020 Jul;32(30):e2000299. doi: 10.1002/adma.202000299. Epub 2020 Jun 21.
The ambient electrocatalytic N reduction reaction (NRR) enabled by TiO has attracted extensive recent attention. Previous studies suggest the formation of Ti in TiO can significantly improve the NRR activity, but it still remains unclear what kinds of Ti are effective. Herein, it is demonstrated that mixed-valent Cu acts as an effective dopant to modulate the oxygen vacancy (V ) concentration and Ti formation, which markedly improves the electrocatalytic NRR performance. In 0.5 m LiClO , this electrocatalyst attains a high Faradic efficiency of 21.99% and a large NH yield of 21.31 µg h mg at -0.55 V vs reversible hydrogen electrode, which even surpasses most reported Ti-based NRR electrocatalysts. Using density function theory calculations, it is evidenced that mixed-valent Cu ions modulate the TiO (101) surface with multiple oxygen vacancies, which is beneficial for generating different Ti 3d defect states localized below the Fermi energy. N activation and adsorption are effectively strengthened when Ti 3d defect states present the splitting of e and t orbitals, which can be modulated by its coordination structure. The synergistic roles of the three ion pairs formed by the V defect, including Cu -Ti , Ti -Ti and Ti -Ti , are together responsible for the enhanced NRR performance.
由TiO实现的环境电催化氮还原反应（NRR）最近引起了广泛关注。先前的研究表明，TiO中Ti的形成可以显著提高NRR活性，但哪种Ti有效仍不清楚。在此，证明了混合价态的Cu作为一种有效的掺杂剂来调节氧空位（V ）浓度和Ti的形成，这显著提高了电催化NRR性能。在0.5 m LiClO 中，该电催化剂在相对于可逆氢电极-0.55 V时达到21.99%的高法拉第效率和21.31 µg h mg 的高NH产率，甚至超过了大多数报道的基于Ti的NRR电催化剂。使用密度泛函理论计算证明，混合价态的Cu离子调节具有多个氧空位的TiO（101）表面，这有利于在费米能级以下产生不同的Ti 3d缺陷态。当Ti 3d缺陷态呈现e和t轨道分裂时，N的活化和吸附得到有效增强，这可以通过其配位结构进行调节。由V缺陷形成的三个离子对，即Cu -Ti 、Ti -Ti 和Ti -Ti 的协同作用共同导致了NRR性能的增强。
