Although the potassium-promoted catalysts exhibit improved catalytic activities, the role of potassium with different structural sites still needs to be studied by more experiments and theory calculation. Herein, potassium (K⁺) formed via different binding sites (isolated and localized) over layered MnO₂ was investigated. The isolated K⁺ dissociated between layers via weak chemical bond while localized K⁺ coordinated with oxygen atoms at vacancy site. K⁺ with localized type (L-MnO₂) exhibited the higher activity and the lower E_a (45.2 kJ/mol), compared with isolated one (58.1 kJ/mol) under 200 ppm HCHO, 120,000 mL/g h GHSV and ∼45% relative humidity. Evidenced by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), hydrogen temperature programmed reduction (H₂-TPR) and density functional theory (DFT) simulation, the isolated K⁺ in interlayer are energetically favourable for dissociation of O₂ as well as H₂O by charge transfer from potassium to oxygen. As a result, the desorption of H₂O was inhibited, thus, became the kinetic barriers during the whole reaction process. K⁺ with localized form possessed suitable ability for O₂ activation and weak adsorption of H₂O, exhibiting enhanced catalytic activity. Inspired by the seesaw effect, a clear understanding of K⁺ effect on layered MnO₂ towards O₂ adsorption and H₂O desorption was illustrated.

尽管钾促进的催化剂表现出提高的催化活性，但是具有不同结构位点的钾的作用仍需要通过更多的实验和理论计算来研究。本文中，研究了通过层状MnO ₂上不同结合位点（分离和定位）形成的钾（K ⁺）。分离出的K ⁺通过弱化学键在层之间解离，而局部K ⁺与空位处的氧原子配位。局部型（L-MnO ₂）的K ⁺表现出较高的活性，而较低的E _a（45.2 kJ / mol），相比之下，在200 ppm HCHO，120,000 mL / g h GHSV和约45％相对湿度下分离出的一个（58.1 kJ / mol）。通过漫反射红外傅里叶变换光谱（DRIFTS），氢温度程序控制的还原（H ₂ -TPR）和密度泛函理论（DFT）的模拟证明，中间层中分离出的K ⁺在能量上有利于O ₂和H _2的解离O通过将电荷从钾转移到氧气来实现。结果，抑制了H ₂ O的解吸，因此成为整个反应过程中的动力学障碍。局部形式的K ⁺具有合适的O ₂活化能力和对H的弱吸附₂ O，表现出增强的催化活性。受到跷跷板效应的启发，阐明了对层状MnO ₂朝向O ₂吸附和H ₂ O解吸的K ⁺效应的清晰理解。