Graphitic carbon nitride decorated with CoP nanocrystals for enhanced photocatalytic and photoelectrochemical H2 evolution
Hongqi Sun Orcid: https://orcid.org/0000-0003-0907-5626
Energy and Fuels
American Chemical Society
School of Engineering
Australian Research Council.
ARC Number : DP150103026, ARC Number : LE120100026
Polydispersed CoP nanoparticles in an orthorhombic phase were synthesized via a gas-solid reaction and then deposited over graphitic carbon nitride to build the CoP/g-C3N4 (CoP-CN) heterostructure. Nanorod-like CoP nanoparticles with a length of 10-80 nm were connected to g-C3N4 nanosheets to build an intimate face-to-face contact via their crystal planes of (011) and (211). This unique heterojunction hybrid exhibits superior photocatalytic and photoelectrochemical performances for H2 evolution and photoelectrochemical response plus excellent overall water-splitting activity. The optimal sample of 3% CoP-CN composite achieved a superior hydrogen production rate at 1038.1 μmol h-1 g-1 when irradiated by simulated solar light, exhibiting a much higher photocurrent at 150 μA cm-2 compared to pure g-C3N4. Also, a larger anodic current density was detected during the photoelectrochemical hydrogen evolution reactions (PEC HERs) with enhanced applied bias photon-to-current efficiency, denoting a higher efficiency for PEC HER. The enhancements for photocatalytic and PEC HER activity are mainly attributed to the formation of intimate interfacial contact for better light absorption, stronger photoreductive potentials, and higher efficiency for charge separation and transfer. This study provides a proof-of-concept design and construction of effective cobalt-phosphide-based heterojunctions for hydrogen evolution and water-splitting applications.