Advanced Photoelectrochemical Hydrogen Generation by CdO-g-C3N4 in Aqueous Medium under Visible Light

Abstract

Herein, hydrothermal fabrication of CdO-g-C3N4 photocatalyst for a substantially better photocatalytic recital in water splitting is presented. The XRD analysis confirms the cubic phase of CdO-g-C3N4, whereas FTIR and UV-VIS studies revealed the presence of respective groups and a median band gap energy (2.55 eV) of the photocatalyst, respectively, which further enhanced its photo-electrochemical (PEC) properties. The SEM displays the oblong structures of g-C3N4 sheets and nano rod-like morphology of CdO and CdO-g-C3N4, respectively. The HR-TEM exhibits morphology & orientation of the grains and substantiates the polycrystal-line nature of CdO-g-C3N4 nanocomposite. The photocatalytic water-splitting concert is evaluated by PEC experiments under 1 SUN visible light irradiation. Linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) comprehend the CdO-g-C3N4 as a hydrogen evolution photocatalyst. A photocurrent density beyond ≥5 mA/cm2 is recorded from CdO-g-C3N4, which is 5–6 folds greater than pure CdO and g-C3N4. The efficient separation and transfer of charges allocated to CdO-g-C3N4 and fabricating heterojunctions between g-C3N4 and CdO suppresses the unfavorable electron-hole pairs recombination process. Thus, it recesses charge transfer resistance, augmenting enhanced photocatalytic performance under 1 SUN irradiation.