The design of materials that efficiently catalyse the electrochemical reaction of molecular oxygen to hydroxide ions is key to the development of electrochemical devices. Here we demonstrate an approach to control the orbital hybridization of 3d and 4d/5d metals to tune the adsorption strength and stabilize the catalytic sites in the platinum-free catalysts Li₂Mn_1−xRu_xO₃. We show that in these materials, the stabilization of O 2p holes by changing the M–O covalency (M = 4d/5d metal) can help to mitigate structural instability. Operando X-ray absorption spectroscopy revealed that the Mn and Ru atoms are the active sites for the oxygen reduction reaction (ORR) and exhibit a high ORR activity with noteworthy stability compared with the Pt/C catalyst and outperform NiFe layered double hydroxides and RuO₂ in the oxygen evolution reaction. Notably, Li₂Mn_0.85Ru_0.15O₃ shows a high power density of 1.2 W cm⁻² and current density of 1.2 A cm⁻² at 1.9 V in the anion exchange membrane fuel cell and water electrolyser, respectively.

有效催化分子氧生成氢氧根离子的电化学反应的材料设计是电化学装置开发的关键。在这里，我们展示了一种控制 3 d和 4 d / 5 d金属轨道杂化的方法，以调节吸附强度并稳定无铂催化剂 Li ₂ Mn _{1− x} Ru _x O ₃中的催化位点。我们表明，在这些材料中，通过改变 M-O 共价键（M = 4 d / 5 d金属）来稳定 O 2 p空穴有助于减轻结构不稳定性。原位X射线吸收光谱显示，Mn和Ru原子是氧还原反应（ORR）的活性位点，与Pt/C催化剂相比，表现出高ORR活性和显着的稳定性，优于NiFe层状双氢氧化物和RuO ₂在析氧反应中。值得注意的是，Li ₂ Mn _0.85 Ru _0.15 O ₃在阴离子交换膜燃料电池和水电解槽中分别在1.9V下表现出1.2W cm ^-2的高功率密度和1.2 A cm ^{-2的电流密度。}