Ni(OH)2 decorated g-C3N4 tubes for precious metal free photocatalytic H2 evolution and the investigation of charge storage mechanism of Ni(OH)2

Precious metal-free photocatalytic H2 evolution (PHE) has been the focus in the PHE field. Herein we report a heterojunction of Ni(OH)2 decorated g-C3N4 tubes (g-C3N4/Ni(OH)2) facilely constructed by hydrothermal process and precipitation, which shows high visible-light photocatalytic performance compared to conventional g-C3N4. The characteristics of the tubular g-C3N4/Ni(OH)2, such as morphology, chemical structure, phase structure, optical and electrochemical properties, were carefully investigated. The results demonstrated Ni(OH)2 as an effective co-catalyst that can store photogenerated charges to promote the separation of photoinduced hole-electron pairs during the photocatalytic process and thus enhance the H2 generation during photocatalytic water decomposition. This work presents the use of non-noble metals Ni(OH)2 as a promising alternative to precious metals (such as Pt and Au) as the co-catalysts in PHE and uncovers the charge storage mechanism of Ni(OH)2 could be extended to other cheap metals.