Correlation between Spin Effect and Catalytic Activity of Two Dimensional Metal Organic Frameworks for Oxygen Evolution Reaction

Abstract

Spin state modulation has been demonstrated an effective strategy to tune the catalytic performance of metal organic frameworks for electrochemical oxygen reduction reaction (OER). However, the undisclosed correlation between spin-state and catalytic activity restricts the application of spin-regulation to electrocatalysis. Here, the spin polarization effect on the catalytic performance of 1,4,5,8,9,12-hexaazatriphenylene (HAT) coordinated transition metal (M3(HAT)2, M = Fe, Co, Ni, Mn, Cr, Ti) monolayers for OER is systematically explored by performing density functional theory calculations. The designed M3(HAT)2 monolayers show good stability and high conductivity because of the d-π conjugation between transition metals and HAT ligands. The spin state of the magnetic metals is quantitatively correlated with the d-band centers, adsorption strength of crucial intermediate, charge transfer amount and overpotential. We suggest spin moment as a promising catalytic descriptor for M3(HAT)2, which allows the rational optimization of catalytic activity by tuning the spin states of the metal center.