宽光谱响应高效人工光合成材料体系构建与机理研究

The “bottle-neck” of artificial photosynthesis (photoreduction of CO2 into hydrocarbon fuels) is the low solar-to-chemical energy conversion. Exploring new-type of wide-spectrum-responsive highly efficient solar energy conversion materials plays a crucial role. In this project, we attempt to explore this kind of materials according to the following three routes: 1) Design and synthesis of new semiconductor-based artifial photosynthetic materials on the basis of enegy band engineering, i.e., with the guidance of enegy band theory, the materials thus developed should be satisfied with the requirements of thermodynamics of artificial photosynthesis while being able to absorb as much as possible to the solar energy; 2) Design and synthesis of nanometal-based artifial photosynthetic materials with wide-spectrum-response to the near infrared range on the basis of local surface plasmonic resonance (LSPR) effect of noble metals; 3) Design and synthesis of whole-spectrum-responsive artifial photosynthetic materials system on the basis of photothermal effect from group VIII metal nanoparticles. Most importanly, the “actitivation of CO2 molecules” is incorporated into the concept of design and synthesis of all aforementioned three materials systems, as the actitivation of nonpolar CO2 molecules is the key step toward its efficient photoreduction. . For the developed materials systems, we employ the state-of-the-art charaterization technologies and the advanced computational methods to study the surface/interface structures, properties, photophysical and photochemical phenomina and mechanisms relating to the artificial photosynthetic process. The findings will provide useful theoretical guidelines for developing highly efficient artificial photosynthetic materials system toward practical application.

人工光合成技术的发展瓶颈是如何大幅度地提高太阳能转换效率，其中，构建具有宽光谱响应的新型高效太阳能转换材料体系起着先决性的作用。本项目拟从以下三个技术途径开展研究：1）基于能带工程的新型半导体人工光合成材料的设计及制备：建立能带调控理论，设计和制备既满足太阳能化学转换热力学条件、又能最大限度利用太阳能的新型半导体材料；2）基于纳米金属的宽广谱响应人工光合成体系的设计及制备：利用纳米贵金属表面等离子共振效应，有效拓展光吸收范围至近红外区；3）基于VIII族金属纳米粒子的全光谱响应人工光合成体系的设计及制备：利用VIII过度族金属光热效应，有效拓展光吸收范围至红外区，使人工光合成体系具有全光谱响应。特别把CO2分子活化贯穿于上述材料体系的整体设计思路。同时，通过先进的表征技术和最新的科学计算方法，阐明上述材料体系中的表/界面现象及光化学反应微观机制，为开发高效人工光合成材料体系提供理论依据。

构建具有宽光谱响应的新型高效太阳能转换材料体系，对于突破人工光合成技术的发展瓶颈起着先决性的作用。本项目实施五年来，在高效人工光合成材料体系开发与相应机理研究等多个方面取得了一系列创新性成果。. (1) 利用能带工程调控电子结构，开发宽光谱响应人工光合成材料体系。Cd负载的Cu掺杂ZnS，实现高效液相CO2光还原；通过d-p轨道杂化设计出高效碳基水氧化电催化材料；晶面肖特基结有效促进光生电荷分离；酸溶液诱导金属还原法制备宽光谱响应WO3-x纳米片阵列光阳极，有效提高光电水分解性能；高浓度氧空位的黑色In2O3-x纳米片，实现高效光热催化CO2还原。(2) 利用纳米金属或非金属等离子效应/光热效应开发宽（全）光谱响应人工光合成材料体系。Ru负载超薄水滑石纳米片实现高效光热催化CO2还原；Au、Pt及Rh等贵金属的LSPR效应耦合大幅降低光热催化CO2及CH4重整的活化能；TaN负载的VIII族金属催化剂实现光热CO2还原；单质硼（B）实现光热催化CO2还原；AlNx辅助单原子镍催化剂首次实现自然光驱动的CO2甲烷化；具有杂化结构的Co@CoN&C有效调控光热催化CO2还原活性及产物选择性；Ni10/Ny-CeO2催化剂实现光热催化CO2还原为CO的100%选择性。(3) 通过催化剂表面活性位点构筑和反应环境调控促进光催化反应。利用缺陷态调控光催化反应表界面能；在CdS上构筑Co(II)分子活性位点实现高效液相CO2光还原；受阻路易斯酸碱对加速CO2光还原；超薄卟啉基金属-有机框架纳米片提高光催化产氢性能；利用ZnS表面阳离子空位实现高效CO2光还原制甲酸；表面氯修饰显著提高BiVO4的光催化水氧化性能。(4) 构建了低成本的太阳能光伏-电解水制氢系统，成功实现15.1%的太阳能-氢能转化效率。. 本项目的研究成果为开发高效人工光合成材料体系提供了重要的理论和实验依据。