Improvement of hydrogen production under solar light using cobalt (II) phosphide hydroxide co-doped g-C3N4 photocatalyst

Abstract

Graphitic carbon nitride (g-C3N4) has been extensively studied as a model of photocatalyst material for water splitting. This study investigates potential of cobalt (II) phosphide hydroxide co-doped g-C3N4 (Co-P/C3N4) for solar water splitting to produce hydrogen gas as a clean energy source. Characterizations of the materials were done using X-ray diffraction, Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, and UV–visible spectroscopy (UV–Vis). Under solar light, the hydrogen production rates per hour using Co-P/C3N4 were 386.8 µmol/g which is 14-fold higher than that of g-C3N4 (28.1 µmol/g). The co-doping of cobalt (II) phosphide hydroxide onto g-C3N4 rapidly improved light harvesting capacity and photo-generated charge carrier separation, leading to increase photocatalytic H2 production. In addition, the reusability of Co-P/C3N4 was confirmed by performing the photocatalytic hydrogen production for five cycles. The material consistently produced H2 without any significant loss in hydrogen productivity. Based on these results, Co-P/C3N4 could be utilized as promising photocatalyst material for production of clean energy.