Computation And Data-Driven Rational Design Of Metal-Organic Frameworks For Oxygen Evolution Reaction

The electrocatalytic oxygen evolution reaction(OER)is a key reaction for the utilization and conversion of green energy,and an excellent electrocatalyst is the key to the efficient utilization of electric energy.Among many electrocatalysts,metal-organic frameworks(MOFs)exhibit excellent OER performance due to their large specific surface area,high atomic accessibility,and strong design flexibility.However,the modular feature of MOFs brings a huge design space,which poses challenges to the experimental-intensive research mode.This paper adopted the basic idea of material genetic engineering,and aimed at a series of common basic issues involved in the development of MOFs,such as composition and structure design,through density functional theory(DFT)and data techniques(correlation analysis,genetic algorithm,crystal graph convolutional neural network),explored the correlation between OER activity with metal active site composition,local chemical environment and active local structure gradually,and established robust and universal OER performance descriptors and prediction models,revealed the physical image behind it,realized the bidirectional index between material microscopic properties and macroscopic OER performance,and clarified the design principles of high-performance MOFs catalytic materials.The specific research contents are as follows:(1)Established the correlation between the electronic characteristics of the metal active sites and the OER performance.Taking the trigonal prismatic secondary building units(SBUs)as the starting point,the DFT calculations,revealed that the electrostatic potential-derived charge(ESPC)is a robust descriptor representing the OER activity of different metal active sites,and verified its applicability to other types of SBUs.Using ESPC as a bridge,it is clear that Ni/Cu as active sites and Mn/Fe/Co/Ni as spectators are the design principles for metal compositions of MOFs.By analyzing the relationship between ESPC with band structure,metal-oxygen species bond order and orbital overlap,the physical correlation between ESPC and OER process is revealed—ESPC correctly represents the binding strength between metal and oxygen species.(2)Revealed the numerical expression of the role of the active local chemical environment on OER performance.Taking two-dimensional conjugate MOFs as the research object,the OER activity of different active local chemical environments(including metal active sites and coordination atoms)was studied by DFT calculation.The correlation analysis and genetic algorithm are used to reveal the nonlinear correlation between the reciprocal of the occupied states of the active site d orbitals and the OER activity.Taking this as a bridge,by analyzing the orbital characteristics of metals and coordination atoms as well as introducing positive charges into the system,the function of metal,coordination atoms and charge effects is clarified,and the essence of the regulation of OER activity by the local chemical environment is revealed.(3)Resolved a high-dimensional complex mapping between the geometric features of the active local structure(ALS)and the OER performance.A knowledge map of the correlation between ALS and OER activity was established through a structural genetic exploration workflow for the first time.The crystal graph convolution neural network(CGCNN)combined with a few DFT simulations remarkably improved the prediction efficiency by～5 orders of magnitude while ensuring high prediction accuracy.Through high-throughput structural generators,over 79000 highly symmetric 5-(oxygen atom)coordinated ALSs with different structural genes were constructed in reverse.Using CGCNN as a performance evaluation engine,structural genes that are beneficial,unrelated,and harmful to OER performance were revealed by a "reverse exploration" manner.It was clarified that the covalent equilibrium distance between active and coordination atoms is 1.85 ? and the larger atomic exposure angle are common structural features of highperformance ALSs,indicating that ALSs should not be excessively pulled by the rest of MOFs.