中国科学技术大学Jun Jiang小组在研究中取得进展。他们的研究使用氮化硼/过渡金属原子/石墨烯薄片夹层结构的单原子催化剂实现高效固氮。 该项研究成果发表在2020年10月27日出版的《美国化学会志》上。

采用第一性原理计算，研究小组报告一个单个过渡金属原子(TM)夹在六角氮化硼(h-BN)和石墨烯薄片(即BN / TM / G)作为一个高效的单原子催化剂(SACs)的电化学氮还原反应(NRR)。这样的夹层结构实现了稳定且可控的界面极化场，使得过渡金属原子向邻近B原子提供电子而成为活性位点。因此，B原子的部分被占据的pz轨道可以与N_²的反键形成B-N 反馈π键, 从而削弱N≡N键。这个h-BN表面不强不弱的电场进一步促进N₂吸附和活化。BN/TM/G体系的NRR催化活性与TM原子正极化电荷的程度具有很高关联性。

特别的是，BN/Ti/G和BN/V/G被认为是有希望的NRR催化剂，具有高稳定性、提供优异能量效率以及抑制竞争产氢反应的性质。

研究人员表示，开发具有高效固氮作用的单原子催化剂(SACs)是非常重要的，同时仍然是一个巨大的挑战。缺乏一个有效的策略来控制单原子催化剂的极化电场限制了他们的活性和和选择性。

附：英文原文

Title: Realizing a Not-Strong-Not-Weak Polarization Electric Field in Single-Atom Catalysts Sandwiched by Boron Nitride and Graphene Sheets for Efficient Nitrogen Fixation

Author: Shaobin Tang, Qian Dang, Tianyong Liu, Shiyong Zhang, Zhonggao Zhou, Xiaokang Li, Xijun Wang, Edward Sharman, Yi Luo, Jun Jiang

Issue&Volume: October 27, 2020

Abstract: Developing efficient single-atom catalysts (SACs) for nitrogen fixation is of great importance while remaining a great challenge. The lack of an effective strategy to control the polarization electric field of SACs limits their activity and selectivity. Here, using first-principles calculations, we report that a single transition metal (TM) atom sandwiched between hexagonal boron nitride (h-BN) and graphene sheets (namely, BN/TM/G) acts as an efficient SAC for the electrochemical nitrogen reduction reaction (NRR). These sandwich structures realize stable and tunable interfacial polarization fields that enable the TM atom to donate electrons to a neighboring B atom as the active site. As a result, the partially occupied pz orbital of a B atom can form B-to-N π-back bonding with the antibonding state of N₂, thus weakening the N≡N bond. The not-strong-not-weak electric field on the h-BN surface further promotes N₂ adsorption and activation. The NRR catalytic activity of the BN/TM/G system is highly correlated with the degree of positively polarized charges on the TM atom. In particular, BN/Ti/G and BN/V/G are identified as promising NRR catalysts with high stability, offering excellent energy efficiency and suppression of the competing hydrogen evolution reaction.

DOI: 10.1021/jacs.0c09527

Source: https://pubs.acs.org/doi/10.1021/jacs.0c09527