In
this work, robust nanocarbons, including graphite (G), carbon
nanotube (CNT), reduced graphene oxide (rGO), carbon black (CB), and
acetylene black (AB), have been successfully coupled into the interfaces
between g-C3N4 and NiS using a facile precipitation
method. The results demonstrated that nanocarbons played trifunctional
roles in boosting the photocatalytic H2 evolution over
g-C3N4, which can not only act as effective
H2-evolution co-catalysts but can also serve as conductive
electron bridges to collect photogenerated electrons and boost the
H2-evolution kinetics over the NiS co-catalysts. More interestingly,
the nanocarbons can also result in the downshift of valence band of
g-C3N4, thus facilitating the fast oxidation
of triethanolamine and charge-carrier separation. Particularly, in
all five ternary multiheterostructured systems, the g-C3N4-0.5%CB-1.0%NiS (weight ratio) and g-C3N4-0.5%AB-1.0%NiS photocatalysts exhibited the highest H2-evolution rates of 366.4 and 297.7 μmol g–1 h–1, which are 3.17 and 2.57 times higher than
that of g-C3N4-1.0%NiS, respectively. Apparently, the significantly enhanced H2-evolution activity of multiheterostructured g-C3N4/carbon/NiS composite photocatalysts can be mainly ascribed to the trifunctional nanocarbons, which serve as the conductive electron bridges rather than the general co-catalysts. More importantly,
it is revealed that the amorphous carbons with higher electrical conductivity
and weaker electrocatalytic H2-evolution activity are more
suitable interfacial bridges between g-C3N4 and
NiS co-catalysts for maximizing the H2 generation. This
work may give a new mechanistic insight into the development of multiheterostructured
g-C3N4-based composite photocatalysts using
the combination of trifunctional nanocarbon bridges and earth-abundant
co-catalysts/semiconductors for various photocatalytic applications.
In the present work, nickel phosphide (NiP) modified graphitic carbon nitride (g-CN) nanosheets were synthesized by a simple grinding method. The structural characterization clearly proved that NiP nanoparticles were well loaded on the surface of g-CN nanosheets. The photocatalytic activity of the composites was tested by catalyzing the reduction of water to hydrogen under visible light irradiation. The results demonstrate that NiP is an efficient co-catalyst for photocatalytic H production of g-CN nanosheets. The maximum photocatalytic H-production rate of 126.61 μmol g h could be obtained by loading 2.0% NiP nanoparticles on the surface of g-CN, which is about 269.4 times higher than that of pure g-CN. It is believed that NiP nanoparticles on the surface of g-CN could act as significant active sites to boost separation of photoexcited electrons and holes and accelerate the H-evolution kinetics, thus achieving greatly enhanced hydrogen generation. It is expected that this work could contribute to further experimental investigation for exploiting the low cost, high-efficiency, and environmentally friendly g-CN-based nanocomposites for photocatalytic H production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.