Oxygen vacancy engineering is an important tool to vary the properties of functional transition metal oxides; however, the selective synthesis of their sub-stoichiometric oxides with a defined composition and electronic configuration is still challenging. Here we describe a rational protocol to prepare mesoporous sub-stoichiometric WO_2.83 through controlled oxygen vacancy formation in mesoporous WO₃. Different from bulk WO₃, the use of a mesoporous WO₃ not only greatly decreases the H₂ reduction temperature, but also causes reduction to WO_2.83 with high selectivity. Oxygen vacancies enable exceptional plasmon resonance in mesoporous WO_2.83, which further could be tailored in a wide range through redox chemistry. Furthermore, mesoporous WO_2.83 exhibits superior hydrogen evolution reaction activity compared to pristine mesoporous WO₃, and it can be shown that the HER activity is crucially dependent on the amount of oxygen vacancies.

中文翻译：

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有序介孔WO _2.83：选择性还原合成，出色的局部表面等离振子共振和增强的析氢反应活性†

氧空位工程是改变功能过渡金属氧化物性能的重要工具。然而，具有限定的组成和电子构型的亚化学计量的氧化物的选择性合成仍然具有挑战性。在这里，我们描述了通过控制介孔WO _3中氧空位的形成来制备介孔亚化学计量的WO _2.83的合理方案。与本体WO ₃不同，中孔WO ₃的使用不仅大大降低了H _2的还原温度，而且还以高选择性将其还原为WO _2.83。氧空位可在中孔WO _2.83中实现出色的等离振子共振，还可以通过氧化还原化学方法在广泛的范围内进行定制。此外，与原始的中孔WO ₃相比，中孔WO _2.83表现出优异的氢释放反应活性，并且可以表明，HER活性至关重要地取决于氧空位的量。