Photocatalytic H₂ Evolution on MoS₂/CdS Catalysts under Visible Light Irradiation

Abstract

Photocatalytic H 2 production on MoS 2 /CdS photocatalysts in the presence of different sacrificial reagents under visible light (λ > 420 nm) has been investigated. The transformation process of the Mo species loaded on CdS, together with the junctions formed between MoS 2 and CdS, was clearly demonstrated with X-ray photoelectron spectroscopy and transmission electron microscopy. Photocatalytic H 2 evolution was optimized for MoS 2 /CdS catalysts. The 0.2 wt % MoS 2 /CdS catalyst calcined at 573 K achieves the highest overall activity for H 2 evolution, and the 0.2 wt % MoS 2 /CdS catalyst demonstrates even higher activity than the 0.2 wt % Pt/CdS, irrespective of different sacrificial reagents used. The junctions formed between MoS 2 and CdS play an important role in enhancing the photocatalytic activity of MoS 2 /CdS catalysts. Electrochemical measurements indicate that MoS 2 is an excellent H 2 evolution catalyst, which is another very important factor responsible for the enhancement of the photocatalytic activity of MoS 2 /CdS catalysts.

Enhanced photoelectrochemical and photocatalytic activities of CdS nanowires by surface modification with MoS2 nanosheets

“…Li et al first reported that the activity of producing H 2 for 0.2 wt% MoS 2 /CdS was enhanced 36 times compared to pristine CdS, which was even higher than 0.2 wt% Pt/CdS under the same reaction conditions [21][22]. Following this work, MoS 2 /CdS nanocomposites with different physical dimensions have been constructed and applied to HER [23][24][25][26][27][28].…”

Two-dimensional inorganic analogues of graphene: transition metal dichalcogenides

“…With the MoS 2 /graphene composite, electrocatalytic HER activity was further enhanced [127] due to a better electrical coupling to the electrode facilitated by graphene [128]. Photocatalytic HER has been carried out with MoS 2 as a co-catalyst in the presence of light-absorbing semiconductors such as CdS [129,130], CdSe [131] and TiO 2 [132], and dyes such as [Ru(bpy) 3 ] and eosin [133]. Incorporation of a small weight per cent of graphene in the composites enhances the activity as graphene can act as an electron sink and promote better charge separation [134].…”

Innovative preparation of MoS2–graphene heterostructures based on alginate containing (NH4)2MoS4 and their photocatalytic activity for H2 generation

“…(10)(11)(12) Exfoliated MoS 2 has also been applied in photocatalysis as co-catalyst in H 2 generation. (13,14) While it has been found that single or few layers MoS 2 do not exhibit itself photocatalytic activity for H 2 generation in the absence of a semiconductor or photosensitizer, MoS 2 can be an efficient co-catalyst to enhance H 2 generation replacing expensive noble metals such as Pt, Pd or Rh. (13,14) Due to the 2D morphology there is an increasing interest in the synthesis of heterostructures of single layer MoS 2 and graphene (G).…”

“…(13,14) While it has been found that single or few layers MoS 2 do not exhibit itself photocatalytic activity for H 2 generation in the absence of a semiconductor or photosensitizer, MoS 2 can be an efficient co-catalyst to enhance H 2 generation replacing expensive noble metals such as Pt, Pd or Rh. (13,14) Due to the 2D morphology there is an increasing interest in the synthesis of heterostructures of single layer MoS 2 and graphene (G). (15-17) MoS 2 -G heterostructures can exhibit synergy and enhanced properties due to the strong interaction between these two components.…”