The photocatalytic activity of different titanium oxide nanowires containing gold (Au@TiO₂NWs), and gold-graphene (Au@TiO₂NWs-graphene), was evaluated by studying the reaction of hydrogen production by water splitting under UV–vis light. The composites showed high surface areas, with values above 300 m² per gram, even after the incorporation of gold and graphene on the surface of titanium oxide nanowires. The highest hydrogen production of Au@TiO₂NWs was 1436 μmol h^–1 g^–1, under irradiation at 400 nm, and with a gold loading of 10 wt %. This photocatalytic activity was 11.5 times greater than that shown by the unmodified TiO₂NWs. For the Au@TiO₂NWs-graphene composites, the highest hydrogen amount obtained was 1689 μmol h^–1 g^–1, at loadings of 10 and 1 wt % of gold and graphene, respectively. The photocatalytic activity of the gold-graphene compounds was 1.2 times greater than that shown by the titanium oxide catalysts and 13.5 times higher than the bare TiO₂NWs. Even at wavelengths greater than 500 nm, the compounds exhibited yields of hydrogen above 1000 μmol h^–1 g^–1, demonstrating the high catalytic activity of the compounds. In addition, TiO₂-based materials are of great interest for energy storage and conversion devices, in particular for rechargeable lithium ion batteries. TiO₂ has a significant advantage due to its low volume change (<4%) during the Li ion insertion/desertion process, short paths for fast lithium ion diffusion, and large exposed surface, offering more lithium insertion channels. However, the relatively low theoretical capacity and electrical conductivity of TiO₂ greatly hamper its practical application. In this work, free-standing electrodes composed by TiO₂NWs and carbon nanotubes, CNT@TiO₂NWs, were used as anode materials for Li-ion batteries. As a result, the electronic conductivity and mechanical properties of the composite were greatly improved and a good cycling performance was obtained in these batteries. This research shows the potential of TiO₂-based materials for the development of new catalysts for hydrogen production and energy storage systems.

中文翻译：

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TiO ₂基纳米材料用于制氢和锂离子电池的开发

通过研究在紫外可见光下水分解产生的氢的反应，评估了不同的含金（Au @ TiO ₂ NWs）和金-石墨烯（Au @ TiO ₂ NWs-石墨烯）的氧化钛纳米线的光催化活性。即使在氧化钛纳米线的表面上掺入了金和石墨烯之后，该复合材料仍具有较高的表面积，其值超过每克300 m ²。在400 nm的辐射下，金负载量为10 wt％时，Au @ TiO ₂ NW的最高产氢量为1436μmolh ^–1 g ^–1。该光催化活性是未改性的TiO ₂ NW所显示的光催化活性的11.5倍。对于Au @ TiO_2种NWs-石墨烯复合材料，在金和石墨烯的负载量分别为10和1 wt％时，获得的最高氢量为1689μmolh ^–1 g ^–1。金-石墨烯化合物的光催化活性比二氧化钛催化剂高1.2倍，比裸露的TiO ₂ NW高13.5倍。即使在大于500 nm的波长下，这些化合物也显示出超过1000μmolh ^–1 g ^–1的氢产率，这表明这些化合物具有很高的催化活性。另外，基于TiO ₂的材料对于能量存储和转换装置，特别是对于可再充电锂离子电池特别重要。二氧化钛₂由于锂离子插入/脱除过程中的体积变化小（<4％），锂离子快速扩散的短路径以及较大的暴露表面，从而提供了更多的锂插入通道，因此具有显着的优势。但是，TiO ₂的相对较低的理论容量和电导率极大地妨碍了其实际应用。在这项工作中，由TiO ₂ NW和碳纳米管组成的自支撑电极CNT @ TiO ₂ NW被用作锂离子电池的负极材料。结果，极大地改善了复合材料的电子导电性和机械性能，并且在这些电池中获得了良好的循环性能。这项研究表明了TiO ₂的潜力基材料，用于开发用于氢气生产和能量存储系统的新型催化剂。