Selective C–O activation of multifunctional molecules is essential for many important chemical processes. Although reducible metal oxides are active and selective towards reductive C–O bond scission via the reverse Mars–van Krevelen mechanism, the most active oxides undergo bulk reduction during reaction. Here, motivated by the enhanced oxide reducibility by metals, we report a strategy for C–O bond activation by doping the surface of moderately reducible oxides with an ultralow loading of noble metals. We demonstrate the principle using highly dispersed Pt anchored onto TiO₂ for furfuryl alcohol conversion to 2-methylfuran. A combination of density functional theory calculations, catalyst characterization (scanning transmission electron microscopy, electron paramagnetic resonance, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy), kinetic experiments and microkinetic modelling expose substantial C–O activation rate enhancement, without bulk catalyst reduction or unselective ring hydrogenation. A methodology is introduced to quantify various types of sites, revealing that the cationic redox Pt on the TiO₂ surface is more active than metallic sites for C–O bond activation.

多功能分子的选择性C–O活化对于许多重要的化学过程至关重要。尽管可还原的金属氧化物具有活性，并通过逆Mars-van Krevelen机理对还原的C-O键断裂具有选择性，但大多数活性氧化物在反应过程中会发生体积还原。在这里，受金属增强的氧化物还原性的影响，我们报告了一种通过用适度还原的氧化物的表面掺杂超低含量的贵金属来活化C-O键的策略。我们演示了使用锚定在TiO ₂上的高度分散的Pt的原理用于糠醇转化为2-甲基呋喃。密度泛函理论计算，催化剂表征（扫描透射电子显微镜，电子顺磁共振，傅立叶变换红外光谱和X射线吸收光谱），动力学实验和微动力学模型的结合揭示了显着的C–O活化速率提高，而没有大量催化剂还原或非选择性环氢化。引入了一种方法来量化各种类型的位点，揭示了TiO ₂表面上的阳离子氧化还原Pt比金属位点对C–O键活化的活性更高。