Enhanced visible-light photocatalytic hydrogen evolution activity of Er3+:Y3Al5O12/PdS–ZnS by conduction band co-catalysts (MoO2, MoS2 and MoSe2)

Abstract

Several conduction band co-catalysts (CBCOs), MoO2, MoS2 and MoSe2, were prepared to improve the visible-light photocatalytic hydrogen evolution activity of Er3+:Y3Al5O12/PdS–ZnS from water splitting, in which the PdS is a valence band co-catalyst (VBCO) used to facilitate the photo-generated hole transfer and the Er3+:Y3Al5O12 is an up-conversion luminescence agent from visible light to ultraviolet light used to provide the ultraviolet light satisfying the energy demands of wide band-gap ZnS photocatalyst. XRD, SEM, TEM and EDX analyses were employed to confirm the morphology, microstructure and composition of the prepared photocatalysts. UV–vis absorption and PL spectra were also determined to explore luminescence effect of the Er3+:Y3Al5O12. The visible-light photocatalytic hydrogen evolution activity of the prepared photocatalysts was evaluated by using Na2S and Na2SO3 as sacrificial reagents in aqueous solution under visible light irradiation. The influential factors such as contents of CBCOs (MoO2, MoS2 and MoSe2) and visible-light irradiation time on visible-light photocatalytic hydrogen evolution of Er3+:Y3Al5O12/PdS–ZnS–MoX2 (X = O, S and Se) were investigated in detail. Particularly, Er3+:Y3Al5O12/PdS–ZnS–MoSe2 with 0.30 wt% MoSe2 shows the highest photocatalytic hydrogen evolution activity.