Cu(I) complexes sensitized ZnO nanorods for photocatalytic water splitting

Abstract

The earth-abundant Cu(I) is one of the promising dye-sensitized photoelectrochemical cells (DS-PECs) for sustainable energy production. We report that the heteroleptic Cu (I) complex's catalysis consisting of diphenylphosphinoaminoacetic acid and bipyridine derivatives have investigated with DS-PECs on water splitting application. HOMO-LUMO energy levels of 2,2′bipyridine Cu(I) diphenylphosphinoaminoacetic acid (Cu(L1)) 4,4′dimethyl-2,2′bipyridineCu(I)diphenyl phosphinoaminoacetic acid (Cu(L2)) are calculated with cyclic voltammetry and Uv-vis spectrometer. Both optic band gap and electrochemical band gap energy levels of Cu(I) complex indicates that Cu(L1) has a narrower band gap (2.74 eV and 2.75 eV) compared with Cu(L2) (2.86 eV and 2.79 eV). The photocatalytic hydrogen production of Cu(L1) and Cu(L2) complexes on ZnO nanorods are monitored with linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in 0.5 M Na2SO4 under 100 mW cm−2 solar light irradiation. Cu(L1) modified ZnO nanorod photoelectrode indicates an utmost photocatalytic response (0.452 mA cm−2), the lowest charge transfers resistance (Rct) against to bare the ZnO and Cu(L2)/ZnO electrodes, and Cu(I) complex decreases injected electron lifetime leading to the enhanced photocatalytic response under solar light irradiation.