含主族s区金属辅酶因子碳材料的制备、电子结构调控与电催化氧还原反应研究

电催化能源转换是能源发展的重要方向之一，其商业化应用依赖于活性高、价格廉的电催化剂。目前，电催化剂的设计是在过渡金属催化的d带中心理论指导下进行的，基于该理论建立了过渡金属d轨道中心位置与反应物种在金属表面吸附自由能的线性关系，进而通过“火山图”设计具有最佳吸附强度的过渡金属基催化剂。与过渡金属局域化的d带不同，主族金属具有离域的s/p带，其表面在吸附分子或原子时会形成宽化的吸附态能级，因而催化活性不高，很少被关注。但在自然界中，以主族s区金属为中心的辅酶因子在一些生化过程中表现出强的活性，因受限于导电性等要求而无法将酶用于电催化领域。本项目拟在理论计算的基础上，将主族s区金属辅酶因子M-Xn（M=Li,Na,K,Ca等，X=N,P,S,O等）镶嵌在类石墨烯中，通过改变M的配位结构来调控其电子结构，使其对氧还原反应中间体有合适的吸附强度，致力于将含主族s区金属碳材料发展成高活性电催化剂。

The s-block metal elements have received little attention in the application of oxygen reduction reactions (ORR) since most previous efforts have been devoted to developing transition metals as electrocatalysts guided by the d-band center model. It is known that the main-group metals and their related materials show poor catalytic activity due to a broadened single resonance derived from the interaction of valence orbitals of adsorbates with the broad s/p-band of main-group metals. However, main-group s block metal cofactors existing in enzymes are extremely active in biochemical reactions. Our density function theory calculations reveal that the catalytic activity of the main-group metals in oxygen reduction reaction is severely hampered by the tight-bonding of active centers with hydroxyl group intermediate. In this project, graphene-based M-Xn（M=Li,Na,K,Ca，X=N,P,S,O et al.）coordinated metal cofactors wil be investigated by both density function theory (DFT) simulations and experimental studies. The variation trends of the s/p-band centers of the main group metals cofactors, the adsorption strength of oxygenated species and the catalytic activity as well will be tuned by changing M local X-coordination. The project would help to find novel highly active ORR catalysts and the concept that tuning the p-electronic density of s-block metal may provide new insight to design other novel main-group metal based single-atom catalysts.