Abstract:

Utilizing abundant and readily available solar and seawater resources to provide sustainable and clean energy to mankind is a far-reaching exploration. In this work, we have designed and synthesized the self-floating solar photothermal composite (Cu/TiO₂/C-Wood) that possesses efficiently full-spectrum solar energy capture and photothermic properties for highly targeted interfacial phase transition reactions that are synergistically favorable for both seawater desalination and hydrogen production. Among them, carbonized wood with abundant microchannel and extremely light mass is used as self-floating carrier to rapidly transports liquid water to localized heating interface by capillary and photothermal effects to achieve effective seawater desalination and water steam production. The plasmonic Cu loaded TiO₂ nanoparticles as catalytic active components trigger surface-dominated photothermally catalytic hydrogen evolution of water steam, realizing the dual-function seawater desalination and synergistic hydrogen production. The hydrogen evolution rate of Cu/TiO₂/C-Wood composite is 179 μmol·h^-1·cm^-2 (35.8 mmol·h^-1·g^-1) under 15 kW·m^-2 and remains basically unchanged after being used 5 times. More importantly, the experimental results show that the main component in seawater-sodium chloride can promote the hydrogen production performance by synergistically concentrated irradiation and self-floating phase transfer process, which breaks the bottleneck of seawater hydrogen production technology, confirming the promising application potential of the self-floating two-phase photo-thermo-catalytic system in large-scale, green and sustainable solar hydrogen production from seawater.

Key words: concentrated solar energy, self-floating, evaporation, synergistic photo-thermo-catalysis, seawater hydrogen production

摘要：

利用储量丰富且易获得的太阳能和海水资源为人类提供可持续的清洁能源是一项具有深远影响的探索。在本工作中，设计合成了一种自漂浮复合材料（Cu/TiO₂/C-Wood），该材料具有高效的毛细输液、全光谱太阳能光热转化及光-热协同催化能力，可通过快速的界面相转移过程实现太阳能驱动海水汽化与水蒸气催化分解制氢的一步协同增效反应。其中，具有大量微通道和极轻质量的碳化木（C-Wood）作为漂浮载体，通过毛细作用将液态水快速输送至局部升温的C-Wood表面，借助高效光热转化过程使海水汽化脱盐，同时负载等离子金属Cu的TiO₂纳米粒子作为催化活性组分触发水蒸气光-热协同催化分解制氢反应，从而实现太阳能驱动高效海水汽化催化分解制氢。实验结果表明：该复合材料在15 kW·m^-2的光照条件下，产氢速率达到179 μmol·h^-1·cm^-2（35.8 mmol·h^-1·g^-1），且在循环利用5次后产氢速率仍基本保持不变。更重要的是，通过聚光太阳能和自漂浮毛细输液条件的共同作用，可以获得海水中主要成分氯化钠对产氢性能的显著促进，从而打破了海水制氢技术一直以来面临的氯离子副作用瓶颈问题，证实了聚光太阳能驱动自漂浮高效光热协同催化体系在规模化、绿色、可持续太阳能海水制氢中的应用潜力。

关键词: 聚光太阳能, 自漂浮, 汽化, 光-热协同催化, 海水制氢