To unravel the role of Ni³⁺ cations in NiO-based catalysts on the reactivity, NiO samples doped by Li⁺, Zn²⁺ and Cr³⁺ cations were prepared to engineer different amounts of lattice and surface Ni³⁺ cations, and probed by CO oxidation. By using experimental and DFT calculation methods, it is disclosed that Li⁺, Zn²⁺ and Cr³⁺ cations have been doped into NiO lattice to generate solid solutions by replacing the lattice Ni²⁺ cations rather than refilling directly into the Ni²⁺ vacancies. Compared with pure NiO, Li⁺ doping promotes the generation of lattice and surface Ni³⁺, but Zn²⁺ and Cr³⁺ doping reduces the generation of Ni³⁺ cations. The quantity of surface active oxygen sites, which is critical to the reactivity, changes proportionally and linearly with the surface Ni³⁺ amount. As a result, the intrinsic CO oxidation activity follows the order of Ni_0.9Li_0.1O > NiO > Ni_0.9Zn_0.1O > Ni_0.9Cr_0.1O, which has proved strongly that the amount of surface Ni³⁺ controls the reactivity. Therefore, the oxidation activity of NiO can be improved by constructing a larger amount of surface Ni³⁺ cations.

为了揭示Ni ³⁺阳离子在NiO基催化剂中的反应活性，制备了由Li ⁺，Zn ²⁺和Cr ³⁺阳离子掺杂的NiO样品，以工程化不同数量的晶格和表面Ni ³⁺阳离子，并进行了探测。通过CO氧化。通过实验和DFT计算方法，发现Li ⁺，Zn ²⁺和Cr ³⁺阳离子已掺杂到NiO晶格中，通过取代晶格Ni ²⁺阳离子而不是直接填充到Ni ^2+中来生成固溶体。空缺。与纯NiO相比，Li ⁺掺杂促进了晶格和表面Ni ³⁺的生成，但是Zn ²⁺和Cr ³⁺掺杂减少了Ni ³⁺阳离子的生成。对反应活性至关重要的表面活性氧位的数量与表面Ni ^3+的含量成比例且线性变化。结果，固有的CO氧化活性遵循Ni _0.9 Li _0.1 O> NiO> Ni _0.9 Zn _0.1 O> Ni _0.9 Cr _0.1 O的顺序，这充分证明了表面Ni ³⁺的量控制反应性。因此，可以通过构建大量的表面Ni ³⁺阳离子来提高NiO的氧化活性。