Scalable one-pot synthesis of phosphorus-doped g-C3N4 nanosheets for enhanced visible-light photocatalytic hydrogen evolution

Abstract Graphitic carbon nitride (g-C3N4) is a prospective visible-light photocatalyst. Two important strategies, nano-structuring and element-doping, are synergistically applied on g-C3N4 to co-improve its activity. Specifically, P-doped g-C3N4 nanosheets were prepared via a facile one-pot approach by calcining dicyandiamide containing NH4Cl and (NH4)2HPO4 as gas-template and P-dopant, respectively. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that the as-obtained g-C3N4 samples are nanosheets structure. UV–Vis spectrometer demonstrated that PCNS-3 showed obvious red shift of absorption edge corresponding to the increased bandgap in comparison with BCN. Photoluminescence (PL) spectra and photocurrent analysis testified the accelerated efficiency of photo-induced electron-hole pairs. It demonstrated a visible-light photocatalytic H2 evolution efficiency 8.9 times that of bulk g-C3N4, benefitting from the increased specific surface area and promoted separation of photo-induced charge carriers. The proposed method is easy to be established and can inspire the scalable synthesis of other element-doped nanoscale g-C3N4.