卟啉系列配体构筑金属-有机框架材料及其阳极析氧电催化性能研究

High overpotential of oxygen evolution reaction in water electrolysis would consume excessive power, leading to low energy conversion efficiency, which is a main challenge in anodic catalyst exploration. Present catalysts such as precious metals, though have good activity and stability, usually are very expensive, setting a main obstacle for their large-scale application. As a candidate, metal-organic frameworks (MOFs) have great potential application in water electrolysis due to their quite large frame structure and specific surface area, which is very beneficial to gather catalytic active sites with high density. .In this research, porphyrin ligands and transitional metal ions with catalytic activity are selected as raw materials. By utilizing synergistic regulation strategy, MOFs with long-range ordered structure, large specific surface area, high conductivity and enriched catalytic active sites are expected to be prepared via directed self-assembly process, of which the electrocatalytic properties for oxygen evolution reaction will be explored. In addition, we will focus on developing non-noble metal MOFs anodes with low overpotential and high activity for catalyzing oxygen evolution reaction, followed by revealing its electrocatalytic mechanism on a molecular level. In summary, our research will uncover the self-assembly rules of porphyrin MOFs, which will greatly enhance our competitiveness in developing suitable anodic electrocatalysts for oxygen evolution reaction.

电催化分解水阳极析氧反应中，过高的析氧过电位需要消耗较高的电能，使得能量转化效率降低。现有的活性好且稳定性佳的贵金属催化剂，普遍价格昂贵，不利于规模化生产。金属-有机框架物(MOFs)通常具有较大的比表面积和有序的框架结构，有利于富集较高密度的催化活性位点，在阳极析氧电催化方面具有重要的潜在应用价值。. 本项目采用协同调控策略，选择具有良好性能的卟啉系列配体与具有催化活性的过渡系列金属离子，通过定向组装制备结构合理、长程有序、高比表面积、高导电性且富含高密度催化活性位点的卟啉MOFs，研究组装规律并考察其阳极析氧电催化性能。筛选具有较低析氧过电位和较高催化活性的MOFs型非贵金属电催化剂，结合其准确晶体结构从分子水平揭示体系的电催化析氧机理。本项目的展开可实现对卟啉MOFs组装过程的规律性研究，提高我国在开发阳极析氧电催化剂方面的竞争力。

本项目选择羧酸系列配体与具有过渡系列金属离子组装得到结构合理、长程有序、高比表面积、高导电性且兼具高密度催化活性位点的金属-有机框架材料（Metal-organic Framework，简称MOF），研究组装规律并考察其电催化性能，寻找并筛选具有较低析氧过电位、较高催化活性和较强催化效率的非贵金属电催化剂。借助MOF准确晶体结构研究不同催化活性中心或框架结构等因素对电催化效率的影响，阐明框架结构因素和金属离子催化活性中心的协同调控作用机理，建立电催化过程的理论模型。通过该项目的研究，能够为基于MOF新型功能材料的开发提供借鉴与指导，探索其在能源技术领域中的应用前景。.首先在MOF框架搭建方面，本项目搭建了20余例MOF，挖掘新型框架结构，注重通过微观结构优化、孔尺寸剪裁、次级结构单元修饰等策略组装新型结构，系统考察了MOF体系的框架结构、稳定性、多孔性和比表面积等因素；随后在电催化剂的构建方面，由MOF作为直接电催化剂部分受限于其导电性和稳定性，项目一方面构筑了卟啉基MOF电催化剂，另还把其作为理想的模板来构筑衍生材料，能够很大程度上继承原始MOF的多孔性、高比表面积、可调节的金属中心和易于功能化且碳含量丰富的有机配体以及均匀分散的活性位点，这有利于分子在孔道中的传输与扩散，以及增强客体分子与活性位点之间的相互接触。因此本项目开发了基于MOF衍生过渡金属硒化物（Transition metal selenides，简称TMSs）的制备作为非贵金属电催化材料，考察其电催化析氢/析氧性能；另一方面，为了改善MOF材料的电导率和成膜性，项目将MOF材料超小超薄化后，作为电化学器件的直接电极材料来构筑新型储能器件，扩展MOF材料的应用范围，为MOF材料在电学器件领域的直接应用进行了深入探索。