Multi-functional photocatalytic activity of transition-metal tetraaza[14]annulene frameworks

Abstract

Multi-functional catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) are highly desired in the development of renewable energy conversion and storage technologies. Using first-principles calculations, we demonstrated the recently-synthesized two-dimensional (2D) metal organic frameworks (MOFs) of transition metals (TM = Cr–Zn, Ru–Ag, Ir, and Pt) atoms and tetraaza[14]annulene (TAA) can deem as multi-functional photocatalysts. Fe-TAA and Rh-TAA MOFs show the bi-functional catalytic activity towards ORR/OER and HER/OER, respectively, while Ir-TAA MOF is a promising tri-functional catalyst for HER/OER/ORR. The catalytic activity of TM-TAA MOFs was revealed to be governed by the binding strength between the TM atom and reaction intermediates, which can be correlated to the d-band center of the TM atoms. Remarkably, the electronic band structures and the photocatalytic activity of Ir-TAA and Rh-TAA MOFs fulfil the requirements of overall water splitting under visible light irradiation. Our findings proposed a new family of 2D MOFs as efficient catalysts for the OER, ORR, and HER in clean energy technologies, offering a promising perspective in catalyst design.