High performance hydrogen photoproduction using Co-doped CuBDC metal organic framework

Abstract

In this study, defect-rich CuBDC metal organic frameworks (MOFs) were engineered by combining the 4-formylbenzoic acid (4-FBA) defective linker with Ni 2+ or Co 2+ dopants. After solvothermal synthesis, Ni 2+ and Co 2+ cations were found homogeneously distributed in CuBDC and the sheet-like structure of the MOF is preserved after doping but its threedimensional organization is modified. The defects generated by the dopants improve both the optical absorption and the lifetime of photogenerated charge carriers compared to CuBDC as demonstrated by UV-visible absorption spectra and photoluminescence. Electrochemical impedance spectroscopy measurements also show that the charge carrier transfer and separation is improved by doping. The photocatalytic activity of the MOFs was evaluated for hydrogen production under visible light irradiation. The highest production rate of H 2 (11176 µmol H 2 g -1 h -1 , based on the mass of MOF) is obtained for Co-CuBDC, value ca. 3.8 times higher than that of CuBDC. This work demonstrates that doping of CuBDC with Co 2+ cations is an effective strategy to prepare photocatalysts with high performance for H 2 evolution.