Rational construction p-n heterojunction Ni(OH)2/NiS2 on g-C3N4 nanosheet to promote the charge carriers separation efficiency for boosting photocatalytic hydrogen evolution

Abstract

The Ni(OH)2/NiS2/g-C3N4 hybrid with sandwich-like structure was successfully designed and synthesized through a solvothermal and condensation reflux method. Furthermore, it should be noted that the p-type Ni(OH)2 was in situ generated on the surface of the n-type NiS2, because the Ni2+ of the Ni(OH)2 came from the NiS2. Therefore, the p-n heterojunction was constructed between the interface of the Ni(OH)2 and NiS2 in the hybrid. Furthermore, the results revealed the optimized Ni(OH)2/NiS2/g-C3N4 hybrid displayed superior H2 evolution property than that of the g-C3N4, NiS2/g-C3N4, and Ni(OH)2/g-C3N4 illuminating with visible-light or simulated-sunlight. The apparent quantum yield (AQY) of Ni(OH)2/NiS2/g-C3N4-6 % at 360, 380 and 400 nm were 1.65 %, 1.31 % and 1.05 %, respectively. Moreover, the resultant Ni(OH)2/NiS2/g-C3N4-6 % hybrid both displayed satisfactory photochemistry durability. Besides this, according to the microstructure and photoelectric property characterizations, theoretical calculation, and in situ XPS test, the promoted H2 evolution property of the ternary catalyst was profit from the synergy impact of the particular sandwich-like structure, and p-n heterojunction. Because they could memorably boost the carriers’ separation efficiency, and offer abundant active sites for H2 production.