Self-assembly of Ni₂P/γ-Ga₂O₃ nanosheets for efficient photocatalytic water splitting hydrogen production

Abstract

Acquirement of the photocatalysts enabling stable and highly efficient water splitting hydrogen production remains an open challenge in the field of energy photocatalysis. Herein, Ni2P/γ-Ga2O3 nanosheets were reported as excellent...

Photocatalytic Overall Water Splitting Reaction Feature on Photodeposited NixP/γ-Ga2O3Nanosheets

“…H 2 O 2 was not detected as a product in the solution during and after the reaction by the conventional KMnO 4 titration. The following characterizations would show that this phenomenon is a result of the formation of surface metal peroxidic species ,− ( e.g. , Ga–O–O–Ga, Ga–OOH) on γ-Ga 2 O 3 by the photogenerated holes.…”

“…The solid samples were finally dried at 60 °C for 12 h in a vacuum and then stored under sealing condition. Pure Ni 2 P was prepared by the solvent thermal method, , while pure Ni x P was prepared by NaBH 4 reduction (as detailed in Supporting Information) , because the Ni x P obtained by photodeposition is extremely unstable in air.…”

“…A set of lattice fringes with 0.248 nm size was identified for NG-30 (Figure 3d,e), which is a feature of the d(311) crystal plane of γ-Ga 2 O 3 . 15,22,23,29 Neither were the lattice fringes of Ni x P or Ni 2 P found, but some species with poorly defined lattice fringes seem to locate on the edge of γ-Ga nanoparticle on the outside of γ-Ga 2 O 3 nanosheets 30,31 and does not change the layered profile of γ-Ga 2 O 3 .…”

“…However, the photocatalytic activity of the composite photocatalyst was found to be seriously degenerative with increasing irradiation time in pure water without methanol. 29 In order to gain an insight into the slow inactivation mechanism of Ni 2 P/γ-Ga 2 O 3 with the reaction time and find a new route to improve the efficiency of the overall water splitting, herein, we prepared Ni x P/γ-Ga 2 O 3 nanosheets by in situ photodeposition of nickel phosphide on a homemade γ-Ga 2 O 3 nanosheet. It is found that the as-loaded nickel phosphide is Ni x P rather than Ni 2 P. Under the same 125 W high-pressure mercury lamp irradiation, the as-prepared Ni x P/γ-Ga 2 O 3 sample exhibits a H 2 productivity as high as 5.5 mmol•g −1 •h −1 in the initial reaction stage, which is two times higher than that on the 0.5 wt % Ni 2 P/γ-Ga 2 O 3 reported previously.…”

“…It was observed that the optimal 0.5 wt % Ni 2 P/γ-Ga 2 O 3 exhibits a photocatalytic hydrogen evolution as high as 2.7 mmol·g –1 ·h –1 in pure water or 12.2 mmol·g –1 ·h –1 in methanol–water solution at room temperature under a 125 W high pressure mercury lamp. However, the photocatalytic activity of the composite photocatalyst was found to be seriously degenerative with increasing irradiation time in pure water without methanol . In order to gain an insight into the slow inactivation mechanism of Ni 2 P/γ-Ga 2 O 3 with the reaction time and find a new route to improve the efficiency of the overall water splitting, herein, we prepared Ni x P/γ-Ga 2 O 3 nanosheets by in situ photodeposition of nickel phosphide on a homemade γ-Ga 2 O 3 nanosheet.…”