宽光谱响应的梯度带隙硫硒化锑薄膜光阴极制备及光电催化分解水制氢性能研究

Photoelectrocatalytic water splitting for hydrogen production has been considered as one of the ideal ways to convert solar energy into fuels. One of the great challenges in the field of photoelectrocatalytic water splitting is to improve the activity and stability of photocathodes and reduce its cost. In this project, the narrow-bandgap Sb2(Se,S)3 will be selected as the photoabsorber owning to its advantageous features such as suitable band positions for hydrogen evolution, low cost, and low toxicity. Highly efficient photocathode is achieved through engineering of gradient bandgap, construction of high-quality p-n heterojunction, and surface decoration with efficient non-noble metal cocatalysts, which can effectively enhance the light harvesting, charge separation and transportation, as well as the activity for hydrogen evolution of Sb2(Se,S)3, respectively. Systematical studies will be carried out to investigate the effects of composition gradient variation and grain size of photoabsorber, band alignment and thickness of wide-bandgap n-type modification layers, activity and coverage of cocatalysts on the activity and stability of Sb2(Se,S)3 photoelectrodes. Using the advanced photoelectron spectroscopy techniques, the band alignments of surface and interface will also be studied, which is helpful for the in-depth understanding on the mechanisms of charge transfer at interface and photoelectrocatalytic reaction mechanism. Based on these studies, the structure-performance relationship between the architecture of photocathode and the resulting photoelectrocatalytic water splitting for hydrogen performance will be revealed, providing insights and feasible ways for the development of broad-spectrum-responsive, highly-efficient, stable, and low-cost photocathode materials.

光电催化分解水制氢是利用太阳能制备燃料的理想途径之一。提高光阴极产氢的活性和稳定性并降低其成本是当前光电催化分解水制氢领域亟待解决的难题之一。鉴于窄带隙硫硒化锑Sb2(Se,S)3具有能带结构合适、价格低廉、绿色低毒等优点，本项目拟选取Sb2(Se,S)3为吸光层，采用梯度带隙工程、高质量p-n异质结构筑及高效非贵金属助催化剂修饰等策略来分别提高硫硒化锑的捕光能力、光生载流子的分离与迁移及催化产氢效率，进而获得高性能的光阴极。系统研究硫硒化锑成分梯度变化与晶粒尺寸、宽带隙改性层的能带结构与厚度、助催化剂的活性与覆盖度等方面对电极的光电化学活性和稳定性的影响，并结合先进的光电谱学表征技术探究表界面能带位置关系，深入理解界面载流子的运输机制和光电催化反应机理，进而揭示电极的结构与其光电催化产氢性能之间的构效关系，为宽光谱响应的高效、稳定、低成本光阴极材料的开发提供科学依据与可行途径。

太阳能驱动光电催化分解水制氢被认为是实现碳中和社会的一种有效技术手段。光电化学分解水制氢的核心研究开发高效及宽光谱响应的光电极新材料。鉴于此，本项目开发了基于梯度窄带隙硫硒化锑Sb2(Se,S)3的复合光阴极材料，我们分别通过硫化改性制备Sb2(Se,S)3多晶薄膜，引入宽带隙n型复合物改性层CdS及ZnO/ZnO:Al构筑高质量p-n异质结，负载非贵金属助催化剂等策略有效提升了其光电催化性能。通过系统研究了硫化条件，晶粒尺寸，n-型改性层能带位置及厚度，助催化剂覆盖度及活性等方面对光电催化活性的影响，揭示了光催化材料结构与光催化性能之间的构效关系。我们的研究工作可为发展高效光阴极材料提供新思路和新方法。