太阳能光催化制氢的科学机遇和挑战

Photocatalytic Production of Solar Fuels: Challenges and Opportunities

面对人类对能源的需求持续增长,以及化石能源的日益枯竭和其带来的环境污染问题,太阳能成为主要的可再生清洁能源的来源。讨论了利用太阳能催化生氢或消耗二氧化碳,探索在半导体基光催化剂表面的光催化反应和光化学反应。半导体材料被认为是最有前景的光催化剂,其材料合成是发展先进催化剂的核心。减少电荷重新复合,是提高太阳能转化为化学能的关键,关系到太阳能的转换效率。研究结果发现了提高光催化制氢的关键因素,通过Pt-PdS/CdS催化体系使其量子效率提高到93%,提供了发展高效催化剂体系的方法。

Solar energy is the primary source for clean and renewable energy alternative. The concerns about the depletion of fossil fuel reserves and the pollution caused by continuously increasing energy demands make solar fuels an attractive energy source. This lecture discusses the key issues concerning the photocatalytic productions of solar fuels, mainly photocatalytic hydrogen production and photoeatalytic reduction of CO2 utilizing solar energy, focusing on the fundamental understanding of photocatalysis and photo chemical reactions on semiconductor-based photocatalysts. Semiconductor materials are believed to be the most promising components for photocatalysts, so the discovery and synthesis of novel semiconductor materials are crucial for the development of advanced photocatalysts. To convert solar energy efficiently to chemical energy, much attention has been paid to reducing charge recombination and improving solar energy conversion efficiency. Our recent results demonstrate that the formation of surface phase junction and hetero-junction on semiconductor catalysts can significantly enhance the activity in photocatalytic hydrogen production. By mimicking the photosynthesis, loading spatially separated dual cocatalysts for oxidation and reduction on semiconductor nanoparticles can effec tively avoid the charge recombination and consequently increase the photocatalytic activity. A recent progress made in photocatalytic hydrogen production shows that a quantum yield up to 93% can be achieved for Pt-PdS/CdS catalysts where the dual co-catalysts, Pt and PdS nanoparticles act as reduction and oxidation co-catalysts respectively. The finely designing and preparation of junctions at atomic and nano-scale together with spatially separated dual co-catalysts findings is a strategy to develop highly active photocatalysts for solar fuel production.