Photocatalytic hydrogen generation via water splitting using ZIF-67 derived Co3O4@C/TiO2

Abstract

Water splitting via photocatalysis using titanium dioxide (TiO2) holds great potential for hydrogen gas generation. Herein, zeolitic imidazolate framework (ZIF-67) was used as a sacrificial precursor for the synthesis of cobalt oxide embedded nitrogen doped carbon (Co3O4@C) that was used as a co-catalyst with TiO2 for the hydrogen generation via photocatalytic water splitting. The optimal loading of Co3O4@C (7 wt%) exhibited a photocatalytic hydrogen production rate (HGR) of 11,400 µmol g−1 h−1. It demonstrated a 75-fold and 110-fold increase for cumulative (5 h) and initial hydrogen generation rates, respectively. The electrochemical measurements such as cyclic voltammetry (CV), linear scan voltammetry (LSV), electrochemical independence spectroscopy (EIS) using Nyquist plots, and photocurrent response were conducted to evaluate the catalytic performance of Co3O4@C/TiO2. Transient photocurrent response showed significant enhancement (4-fold) in photocurrent density of TiO2. Co3O4@C promoted the photocatalytic performance of TiO2 and improved the HGR. The photocatalysis using Co3O4@C/TiO2 is recyclable for more than four cycles without significant loss of their performance. The results of our study may open the door for further exploration toward effective photocatalyst.