A series of nanocrystalline titanium (Ti) sub-oxides, including TiO, Ti₂O₃, Ti₃O₅, and Ti₄O₇, with high surface area and activity are successively synthesized using a facile synthesis method that combines the sol–gel and the energy-efficient vacuum-carbothermic (SG-VC) processes. The combination results in synergy in producing nanomaterials with high surface area (>100 m² g^–1), good conductivity, and rich intra-grain defect features, giving the oxides unique surface activities suitable for particular electrochemical applications. The phase compositions of the resulting powders are primarily determined by two process parameters, including the carbothermic carbon (C) content, expressed as the C-to-Ti molar ratio of the reactant powder, and the cooling protocol. Carbothermic C contents exceeding a threshold of C/Ti ∼ 3.7 exclusively produced non-Magnéli phase (MP) oxides including TiO and Ti₂O₃, while the MP oxides, Ti₃O₅ and Ti₄O₇, can be formed only with lower C contents combined with selected quenching protocols that kinetically limit oxygen replenishment during cooling. Examples of the resulting MP Ti₄O₇ powder exhibiting outstanding pseudocapacitive and oxygen evolution reaction catalytic behaviors are demonstrated.

中文翻译：

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溶胶-凝胶法和真空碳热法相结合合成用于电化学的高性能钛亚氧化物

一系列的纳米晶钛（Ti）亚氧化物，包括TiO，Ti ₂ O ₃，Ti ₃ O ₅和Ti ₄ O ₇，具有很高的表面积和活性，是使用一种简便的合成方法相继合成的，该方法结合了溶胶-凝胶和节能的真空碳热（SG-VC）工艺。结合在一起可产生具有高表面积（> 100 m ² g ^–1的纳米材料）的协同作用），良好的导电性和丰富的晶粒内缺陷特征，使氧化物具有独特的表面活性，适合特定的电化学应用。所得粉末的相组成主要由两个工艺参数确定，包括碳热碳（C）含量（表示为反应物粉末的C-Ti摩尔比）和冷却方案。碳热C含量超过C / Ti〜3.7的阈值时，仅产生包括TiO和Ti ₂ O _3的非马格尼利相（MP）氧化物，而MP氧化物Ti ₃ O ₅和Ti ₄ O ₇只能以较低的C含量结合选择的淬灭方案形成，该淬灭方案在动力学上限制了氧气在冷却过程中的补充。所得MP Ti ₄ O ₇粉末的实例显示出优异的拟电容性和析氧反应催化行为。