Optimizing kinetic barriers of ammonia synthesis to reduce the energy intensity has recently attracted significant research interest. The motivation for the research is to discover means by which activation barriers of N2 dissociation and NHz (z = 1-2, surface intermediates) destabilization can be reduced simultaneously, i.e., breaking the "scaling relationship". However, by far only a single success has been reported in 2016 based on the discovery of a strong-weak N-bonding pair-transition metals (nitrides)-LiH. Described herein is a second example which is counter-intuitively founded upon a strong-strong N-bonding pair unveiled in a bifunctional nanoscale catalyst TiO2-xHy/Fe (where 0.02 ≤ x ≤ 0.03 and 0 < y < 0.03), in which hydrogen spillover (H) from Fe to cascade oxygen vacancies (OV-OV) results in the trapped form of OV-H on the TiO2-xHy component. The Fe component thus enables facile activation of N2 and H2, while the OV-H in TiO2-xHy hydrogenates the NHz to NH3 easily.

中文翻译：

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氢溢出到 TiO2-xHy/Fe 的氧空位：打破氨合成的比例关系

优化氨合成的动力学障碍以降低能量强度最近引起了重大的研究兴趣。研究的动机是发现可以同时减少 N2 解离和 NHz（z = 1-2，表面中间体）不稳定的激活障碍的方法，即打破“缩放关系”。然而，到目前为止，2016 年仅报告了一次成功，因为它发现了强弱 N 键对 - 过渡金属（氮化物）-LiH。这里描述的是第二个例子，它违反直觉地建立在双功能纳米级催化剂 TiO2-xHy/Fe（其中 0.02 ≤ x ≤ 0.03 和 0 < y < 0.03）中的强-强 N 键对上，其中氢从 Fe 溢出 (H) 到级联氧空位 (OV-OV) 导致 TiO2-xHy 组分上捕获形式的 OV-H。因此，Fe 组分可以轻松激活 N2 和 H2，而 TiO2-xHy 中的 OV-H 很容易将 NHz 氢化成 NH3。