Ni1-xFexOOH/掺杂g-C3N4/TiO2纳米复合材料的光电化学性能与界面反应动力学研究

One of the most popular research for hydrogen production with solar water splitting is the preparation of highly efficient and stable photoelectric catalysts and their interface reaction kinetics problems . Based on our previous research work, the construction of doped g-C3N4 and Ni1-xFexOOH co-modified titanium dioxide is proposed because of the drawbacks of titanium dioxide, including a slow interface reaction rate and low photoelectric conversion efficiency. A higher photoelectric conversion efficiency of the photoelectric catalyst is obtained by optimizing the preparation conditions and taking fully advantage of these merits, which includes the layered structure and special photocatalytic properties of g-C3N4, and the promoting the interfacial reaction of Ni1-xFexOOH. We will explore simultaneously the mechanism of the co-catalyst Ni1-xFexOOH and the interface reaction kinetics of the photo-generated carriers, and also quantitatively analyze the interface charge transfer rate constant of the photo-electrode. All these research are based on the feedback working mode and the in-situ monitoring system of scanning electrochemical microscopy. This project intends to solve the critical issue of a slow interface reaction rate and low photoelectric conversion efficiency of titanium dioxide. The mechanism of the charge transfer in the interface and its influencing factors would be investigated, and the associated problems between the modified materials and charge transfer in the interface of the photo-electrode would be explored. This study will provide new ideas for designing and preparing the materials with high performance, which has important guiding significance in theory.

高效、稳定光电催化剂及其界面反应动力学是目前太阳能分解水制氢领域的研究热点。基于前期研究基础，针对二氧化钛存在光电转换效率低和电极界面氧化反应速率慢等缺点，我们提出了构建掺杂g-C3N4和Ni1-xFexOOH共修饰二氧化钛的方案。利用掺杂g-C3N4的层状结构和光催化特性，以及Ni1-xFexOOH促进界面反应的优势，并通过优化工艺条件，最终获得高光电转换效率的复合型光电催化剂。借助扫描电化学显微镜原位监测电极界面反应的优势，揭示助催化剂Ni1-xFexOOH的作用机制，重点研究光生载流子在复合光阳极界面上的转移动力学过程，并定量分析复合光阳极催化界面电荷转移速率常数。本项目拟解决二氧化钛光电转换效率低和界面反应速率低等关键问题，研究光电催化界面电荷转移物理机制及其影响因素，发掘修饰剂与光电极界面电荷转移之间的关联问题，为高性能光电极材料的设计和制备提供新思路，具有重要的理论指导意义。

开发高效、稳定的光电催化剂，研究界面反应动力学和催化剂的作用机制一直是太阳能分解水领域的研究热点和难点，本项目制备了一系列以二氧化钛纳米棒（TiO2 NRs）为基底的复合光电极，主要包括硼掺杂氮化碳修饰二氧化钛纳米棒，金和磷掺杂氮化碳共修饰二氧化钛纳米棒，碳点和氮化碳共修饰二氧化钛纳米棒，Ni1-xFexOOH修饰二氧化钛纳米棒等复合光电极，并研究了这些复合光电极的光电催化分解水性能。作用机制研究方面，我们利用扫描电化学显微镜研究了碳点和氮化碳共修饰二氧化钛纳米棒复合光电极的光电催化活性提高的作用机制，并利用强度调制光电流谱技术研究了Ni:FeOOH增强光电催化分解水性能的作用机制。基于材料设计思路和作用机制研究，我们还拓展了研究内容，制备了石墨烯修饰镍掺杂羟基氧化铁并研究了其电催化/光电催化分解水的性能。此外还研究了助催化剂Ni:FeOOH在光电催化分解水领域的普适性。这些研究成果为构筑高性能光阳极材料和研究界面反应动力学提供了良好的设计思路和技术途径。