可见光催化还原制备FeNi双金属合金催化剂并原位产氢与加氢反应研究

Bimetallic catalysts, due to the synergistic effects between the two individual metal components as well as the great variability incatalysts' components, structure and properties, shows obviously enhanced metallic properties in specific aspects, and have found wide-spread applications in catalysis, especially in catalytic hydrogen production and hydrogenation reactions. In view of saving resources, this project would utilize the visible light induced photoreduction methods to prepare non-precious, earth-abundant (FeNi) nanoparticle catalysts in an in-situ, one-step and controlled manner. Simultaneous photocatalytic hydrogen evolution was expected to happen during the catalyst preparation process and investigations will be carried out on the photoreduction of NO3- to NH3 with in situ generated bimetallic catalysts and hydrogen gas, which will effectively save energy and reduce the discharge of CO2 during NH3 synthesis process. As far as we know, this multifunctional visible light induced photocatalytic system is not yet reported both at home and abroad. Our project would systematically investigate the light triggered bimetallic-catalyst-formation mechanisms, with an emphasis on clearing out the corresponding component-structural-property relationship, and have in-depth insights into the effect of intermediate formated by surface H interactions with the bimetallic catalysts on the catalytic reduction process. In addition, theoretical calculations will also be harnessed to confirm the active reaction site located on the surface of bimetallic catalysts, which will not only help to reveal the microscopic interaction mechanisms and tunable rules happening on the surface molecular level physical-chemical processes, but also contribute to interpretation of catalytic hydrogen evolution and hydrogenation mechanisms. Based on the above investigations of the structural-property relationship, we would further launch studies on whole-scale design and preparation of bimetallic catalysts, with the eventual goal of developing the optimized catalysts with enhanced catalytic activities.

双金属催化剂由于两种金属元素协同效应的存在以及组分、结构、属性上极大的可变性，明显提升金属的某些特定性能，使其在催化领域尤其是催化产氢及加氢方面有广泛的应用。为节省资源，本项目旨在利用可见光催化手段、一步可控还原制备系列非贵双金属（FeNi）合金催化剂，并进行原位分解水产氢，及利用产生的氢进行原位光催化还原NO3-生成NH3等加氢反应研究，有效节约能源并降低NH3合成中CO2的排放。该可见光体系在国内外还未见报道；我们将系统研究光诱导双金属合成机理，重点阐明双金属合金的组成-结构-性能的对应构性关系，深入认识双金属合金催化剂与表面产生的氢形成的中间体对催化还原的影响，利用理论计算等研究确定双金属表面的活性位点，揭示发生在界面的分子物理化学过程的微观作用机制及调控规律，探索光催化产氢及加氢过程反应的机理。并在已知构效关系的基础上，对双金属催化剂进行整体设计与合成，优化制备出性能更好的催化剂。

围绕研究目标和研究内容的要求，项目研究进展顺利，我们较好的完成了本项目的研究计划任务，实现了预期目标。针对本项目提出的利用光催化还原手段制备结构特征突出、物理参数均一的双金属纳米合金的同时，并进行原位光催化产生氢气，以及利用产生的氢气进行原位加氢实验要求，我们成功原位光催化还原制备了FeNi合金，该FeNi合金显示了较高的催化活性和稳定性；并系统研究了不同尺寸，形貌等对构效关系。进一步我们合成制备了具有类双金属性质的金属磷化物、硫化物等催化剂M（Fe，Co，Ni）P（S），这些催化剂与CdS复合在一起在有牺牲剂的条件下显示了到目前为止最高的产氢活性与稳定性，并进行了硝基还原和CO2还原等加氢实验。我们系统研究了双金属合金的组成、结构、尺寸等结构对活性的影响，并从机理上探究了双金属催化剂的活性位点，光诱导电子转移的协调控制等，为强化太阳能有效利用及化学转换效率的提高，揭示其内在的作用规律提供了更多的实验数据。在此项目执行过程中以第一或通讯作者发表包括ACS Cata., Chem. Commun., J. Mater. Chem.A, Appl. Catal. B, Environmental, ACS Appl. Energy Mater. 等SCI论文13篇，其中单篇引用最高位45次，目前正在申请国家发明专利2 项。