The distribution and coordination states of surface oxygen and metal ions in pure-phase metal oxides are dominated by the exposed crystal facets, which directly affects its physicochemical properties. Herein, we have elaborately constructed three catalysts of single-crystalline α-MnO₂ nanowires with predominantly exposed {3 1 0}, {1 1 0} and {1 0 0} facets, respectively. The α-MnO₂ catalyst exhibits a strong facet-dependent catalytic activity for the three-phase reaction of catalytic soot oxidation. Compared with the low-index {1 1 0} and {1 0 0} facets, the α-MnO₂ catalyst with exposed high-index {3 1 0} facet exhibits the highest catalytic activities (T₅₀ = 333 °C, TOF = 1.127 h⁻¹), the lowest apparent activation energy (68.4 KJ mol⁻¹), and excellent catalytic stability during soot oxidation. Combining the results of characterizations and density functional theory (DFT) calculations, the intrinsic mechanism of crystal facet-dependent catalytic activity for soot oxidation is revealed: The selectively exposed α-MnO₂{3 1 0} facets can induce the formation of coordinative unsaturated atoms and surface defect sites, enhancing the adsorption-activation ability for O₂ and NO. In-depth understanding of the face-dependent catalytic activity of α-MnO₂ catalyst is valuable for the acquisition of high-efficient non-precious metal catalysts during soot oxidation.

纯相金属氧化物中表面氧和金属离子的分布和配位状态以裸露的晶面为主，直接影响其理化性质。在此，我们精心构建了三种单晶α-MnO ₂纳米线催化剂，分别具有主要暴露的{3  1  0}、{1  1  0}和{1  0  0}晶面。α-MnO ₂催化剂对催化烟炱氧化的三相反应表现出很强的晶面依赖性催化活性。与低指数{1  1  0}和{1  0 0}晶面相比，暴露出高指数{3 1 的α-MnO _2催化剂  0}面表现出最高的催化活性（T ₅₀  = 333 °C，TOF = 1.127 h ^-1），最低的表观活化能（68.4 KJ mol ^-1），以及在烟灰氧化过程中优异的催化稳定性。结合表征和密度泛函理论（DFT）计算的结果，揭示了晶面依赖的烟尘氧化催化活性的内在机制：选择性暴露的α-MnO ₂ {3  1  0}晶面可以诱导配位不饱和的形成原子和表面缺陷位点，增强了对 O ₂和 NO的吸附活化能力。_{深入了解α-MnO 2}的面依赖性催化活性催化剂对于在烟灰氧化过程中获得高效的非贵金属催化剂具有重要意义。