过渡金属基多层膜界面调控与生长及其光/电协同催化作用的机制研究

Utilizing solar energy and electric energy to achieve hydrogen evolution, CO2 reduction and NOx transformation is a hot research topic in the field of energy and environment. How to effectively cooperate with light and electron to realize green energy conversion is still a difficult problem, mainly due to the mismatch in the energy level and crystal face between photocatalytic and electrocatalytic materials, which results in serious ohmic polarization and diffusion polarization, restriction on the photo-induced charge transfer, and other issues, and thus affects the synergy effect. In this project, the transition-metal based multi-layered electrodes will be designed to realize the photo-electrical synergistic catalysis. According to the matching principle of energy level and crystal face, photoactive materials with porous or array structure are proposed to synthesize on the electrocatalytic films of transition-metal phosphides (sulfides or oxides) via in situ controlled epitaxial growth strategy, and then forming multilayered photo-electrodes. In view of the material characteristics, the multilayered photo-electrodes will further be used as anode and cathode for oxidation and reduction reaction, respectively. The efficient photo-electrodes with close-contact structure and exposed active sites will be obtained by the chemical regulation of multilayer structure, leading to the weakened interfacial polarization. On this basis, the self-consistent and coupled photo-electrical reaction cells for synergistic catalysis will be fabricated to oxidize NOx and other pollutants in anode, and produce hydrogen and reduce CO2 in cathode, which can improve the energy efficiency and catalytic efficiency. Combined with theoretical calculation and in situ spectroscopy technology, exploring the synergy-catalysis mechanism will pave the way for the high-efficient photo-electrical synergistic reaction, and promote the practical application process.

利用光能和电能催化析氢、CO2还原和NOx转化是能源和环境领域的研究热点。如何有效协同光能和电能实现绿色能源转化仍是难题，主要原因是光、电材料间能带、晶面等不匹配导致欧姆极化和扩散极化严重、光生电荷传输受限等问题，影响协同功效。本项目提出制备兼具光催化和电催化活性的过渡金属基多层结构电极的设想。依据能级和晶面匹配原则，在过渡金属基（磷、硫、氧化物）电催化薄膜表面可控地外延生长多孔、阵列结构的光活性材料，构筑多层结构电极，并根据材料特性分别用于光/电协同催化氧化、还原反应。通过对多层结构的化学调控，有效削弱界面极化，获得接触紧密且活性位暴露的光/电协同催化电极。在此基础上构建耦合、自洽的光/电协同催化反应池，提高阳极氧化处理NOx等污染物和阴极析氢、CO2还原反应的能量利用率和催化效率。理论计算结合原位光谱技术探究协同催化反应机制，为实现高效光/电协同催化反应奠定基础，以加速其实用化进程。

本项目针对光、电催化分解水、有机物转化和CO2还原等能量转化体系的关键科学问题和反应本质开展研究。依据材料的电子学特性和能带结构等特征，设计合成了高效的能量转化催化材料。发展了基于超分子组装的合成新策略，构筑了多孔氮化碳薄层以及C/N比可调的氮化碳集束体，实现了氮化碳能带结构的精确调整，并利用Cu点缀显著改善了氮化碳载流子的面内和层间分离/转移效率，实现了高效的光催化分解水产氢。根据能带结构特点，构建了TiO2基串联异质结光催化材料，促进了光生载流子的高效分离和转移，延长了光生电荷的寿命，并将光吸收拓展至可见-近红外光区，提升了光催化性能。基于前、后过渡金属d电子的弥补效应和s/p-d电子调整作用，设计了过渡金属间隙化合物和Sn（Bi）基电催化材料，优化了电催化分解水和CO2还原反应中间体吸附态；结合表面点缀、原位造孔、三维立体膜构建等方法，有效削弱电极界面电阻，促进催化反应过程中反应物传质和扩散，降低扩散极化。针对水氧化半反应动力学缓慢、能耗高、产物加值低等问题，将有机物氧化反应与析氢反应耦合，在低能耗下析氢的同时获得高附加值化学品。结合原位表征手段和理论模拟等方法，研究工况下材料电子态和结构变化，揭示光（电）催化反应过程的电荷转移过程和反应中间物种的吸附形态，从微观层面上认识催化反应机制，实现了材料可控制备、电子态调控与实际功效之间的有效链接。.项目执行期间，在J. Am. Chem. Soc.、Angew. Chem. Int. Ed.、Adv. Mater.等国际、国内重要学术期刊上发表论文88篇（IF>8，67篇），其中13篇入选ESI top 1%高被引论文，3篇入选ESI top 0.1%热点论文，1篇入选2019年中国百篇最具有影响国际学术论文；获授权中国发明专利8项，日本、韩国和美国发明专利各1项；获2018年黑龙江省科学技术发明一等奖。共培养硕士博士研究生40余人，已有28人获得硕士/博士学位。