In addition to the extended light absorption, the effective spatial charge separation is a crucial factor for highly efficient metal-oxide semiconductor-based photocatalysts. Herein, a rational design of metal-semiconductor-metal nano heterostructure for enhancing photocatalytic performance is proposed. The semiconductor nanoparticles are integrated with two metals in one single nano heterostructure. The disordered layers are induced on the surface of TiO₂ to promote the light absorption capacity. More importantly, the n-n⁺ junction is fabricated at the contact region between crystalline TiO₂ (n-TiO₂) and disordered layers (n⁺-TiO₂). Besides, the Schottky diode and Ohmic contact are formed on n-TiO₂ and n⁺-TiO₂, respectively. As a result, the existence of multi-junctions leads to the formation of multiple continuous built-in electric fields, thus remarkably accelerating the spatial separation of charge carriers. The resulting nano heterostructure with multi-junctions (Pt–TiO₂–H–Ag) exhibits remarkably promoted photocatalytic performance. The maximum hydrogen generation rate of Pt–TiO₂–H–Ag under solar illumination (18001.0 μmol/h/g) is 8.3, 9.3, and 1.5 times superior to that of Pt-loaded P25 (Pt–P25), Pt loaded TiO₂ (Pt–TiO₂), and hydrogenated Pt–TiO₂ (Pt–TiO₂–H), respectively. Moreover, the photocatalytic performance under visible illumination is significantly enhanced by Pt–TiO₂–H–Ag. Specifically, the H₂ generation rate of Pt–TiO₂–H–Ag (2382.7 μmol/h/g) is about 15.1, 17.2, and 1.4 times higher than that of Pt–P25, Pt–TiO₂, and Pt–TiO₂–H, respectively. The corresponding apparent quantum efficiency of Pt–TiO₂–H–Ag is 15.8% (420 nm). The nano heterostructure with multi-junctions also exhibits excellent stability after five cycles, remaining hydrogen evolution rates of 15581.5 and 2211.4 μmol/h/g under solar and visible illumination, respectively. This effective and controllable manufacturing strategy could provide new opportunities to simultaneously extend optical absorption and facilitate the spatial charge separation and transport of wide-bandgap metal-oxide semiconductors.

除了扩展的光吸收之外，有效的空间电荷分离对于高效的基于金属氧化物半导体的光催化剂也是至关重要的因素。本文提出了一种合理设计金属-半导体-金属纳米异质结构以提高光催化性能的方法。半导体纳米颗粒在单个纳米异质结构中与两种金属结合在一起。在TiO ₂的表面上诱发无序层，以提高光吸收能力。更重要的是，在晶体TiO ₂（n-TiO ₂）与无序层（n ⁺ -TiO ₂）之间的接触区域处制造nn ⁺结。）。此外，肖特基二极管和欧姆接触分别形成在n-TiO ₂和n ⁺ -TiO ₂上。结果，多结的存在导致形成多个连续的内置电场，从而显着加速了电荷载流子的空间分离。由此产生的具有多结（Pt–TiO ₂ –H–Ag）的纳米异质结构表现出显着提高的光催化性能。在日光照射下（18001.0μmol/ h / g）Pt–TiO ₂ –H–Ag的最大氢生成速率是Pt负载的TiO的Pt负载的P25（Pt–P25）的8.3、9.3和1.5倍₂（Pt–TiO ₂）和氢化的Pt–TiO ₂（Pt-TiO ₂ -H）。此外，Pt-TiO ₂ -H-Ag可显着提高可见光下的光催化性能。具体而言，Pt–TiO ₂ –H–Ag（2382.7μmol/ h / g）的H ₂生成速率比Pt–P25，Pt–TiO ₂和Pt–TiO高约15.1、17.2和1.4倍₂ –H。Pt–TiO ₂的相应表观量子效率–H–Ag为15.8％（420 nm）。具有多结的纳米异质结构在五个循环后也表现出优异的稳定性，在太阳和可见光下的氢释放速率分别为15581.5和2211.4μmol/ h / g。这种有效且可控的制造策略可以提供新的机会，同时扩展光学吸收并促进宽带隙金属氧化物半导体的空间电荷分离和传输。