Two Water Stable Copper Metal-Organic Frameworks with Performance in the Electrocatalytic Activity for Water Oxidation

Xiuping Liu,Wenyue Guo,Wenwen Liu,Lianming Zhao,Yijun Wang,Huining Xiao

doi:10.1051/matecconf/201814201004

Abstract

Two novel water stable metal-organic frameworks, [Cu(L)·(4,4′-bipy)·(ClO4)]n (1), [Cu(L)·(phen)·(ClO4)·(H2O)]2 (2), have been constructed by HL=[5-Mercapto-1-methyl] tetrazole acetic acid and Cu (II) salt in the presence of assistant N-containing ligands. MOF 1 and MOF 2 with open CuII sites, resulting the framework 1 and 2 show electrocatalytic activity for water oxidation in alkaline solution. The electrochemical properties of complex for oxygen evolution reaction (OER) were evaluated by linear sweep voltammetry (LSV) and the Tafel slopes. Complex 1 has a higher LSV activity with a lower over potential of 1.54 V and a much higher increase in current density. Meanwhile, the Tafel slope of complex 1 (122.0 mV dec-1) is much lower than complex 2 (243.5 mV dec-1). This phenomenon makes complex 1 a promising porous material for electrocatalytic activity.

Highlights

Metal−organic frameworks (MOFs), as a new and vital class of porous crystalline materials, have received considerable attention in the past decades for their potential applications in the adsorption, catalysis, biology and others.[1]
We present the syntheses, crystal structures and the oxygen evolution reaction (OER) properties of the two complexes, namely [Cu(L)( 4,4′-bipy)]n (1), [Cu(L)(phen)]n (2), which incorporates 4,4′-bipy and phen ligands respectively
The 2D infinite chains were further stacked into a three-dimensional supramolecular framework through π-π stacking and weak interactions (Fig. 1a)

Summary

Introduction

Metal−organic frameworks (MOFs), as a new and vital class of porous crystalline materials, have received considerable attention in the past decades for their potential applications in the adsorption, catalysis, biology and others.[1]. Some reports have shown that most of MOFs are unstable and lose their structural when exposed in water. Because the relatively weak metal−oxygen bonds within the frameworks are attacked by water molecules and lose their structures.[2] the incorporation of hydrophobic functional groups within the frameworks might largely enhance the M-O bonds and improve the water resistance of the MOFs in an efficient manner. The well-established catalysts for water oxidation up to now are mainly recorded as some precious metals or traditional metal materials,[6] and the MOFs used for OER are nearly unexplored.[7] In this context, we present the syntheses, crystal structures and the OER properties of the two complexes, namely [Cu(L)( 4,4′-bipy)]n (1), [Cu(L)(phen)]n (2), which incorporates 4,4′-bipy and phen ligands respectively

Reagent and instruments

C16ClCuN6O7S

Electrochemistry activity

Summary