CdS/Metallic Mo Hybrid Photocatalysts with Highly Active Interfacial Mo–O–S Active Sites for Efficient Photocatalytic Hydrogen Evolution under Visible Light

Abstract

Engineering an intimate interface with abundant active sites between a semiconductor and a cocatalyst is highly attractive in facilitating the charge separation and thus photocatalytic H 2 evolution performance of the resultant hybrid photocatalyst. Herein, we demonstrate that hybridizing CdS with metallic Mo nanoparticles leads to CdS/Mo photocatalysts with abundant interfacial Mo−O−S active sites resulting from the in situ reaction of surface S on CdS with native MoO x on Mo nanoparticles. The CdS/Mo hybrids exhibit a 23 times higher H 2 evolution rate (30.1 mmol h −1 g −1 ) than pristine CdS under visible light irradiation (≥420 nm), and the highest apparent quantum efficiency (AQE) obtained at 420 nm is as high as 43.2%. Interfacial Mo−O−S species are revealed to play an important role in promoting the charge separation on CdS and also serve as active sites for the H 2 evolution reaction. In parallel, comparative experiments indicate that the hybrid photocatalyst of metallic Mo with surface S-free TiO 2 or g-C 3 N 4 hardly exhibits enhanced H 2 evolution activities, further highlighting the important cocatalytic role of the in situ generated interfacial Mo−O−S active sites in photocatalytic H 2 evolution on CdS/Mo photocatalysts. This work emphasizes the potential of interfacial engineering in designing highly efficient photocatalysts for solar energy conversion.

Pyroelectric effects in CdS phase junctions for dual-enhanced photocatalytic hydrogen production

“…At the same time, the surface of CdS has few exposed active sites, limiting the photocatalytic activity, which can be increased by engineering an intimate interface with abundant active sites between a semiconductor and a cocatalyst. [23][24][25][26] This offers a broad prospect for H 2 production by pyroelectric properties. However, in the process of pyroelectro-catalytic H 2 evolution for CdS, the low separation efficiency of photo-generated carriers is similar to the problem in photocatalytic water splitting.…”

Edge Rich Ultrathin Layered MoS2 Nanostructures for Superior Visible Light Photocatalytic Activity

“…In addition, the hydrothermal method is very promising for preparing MoS 2 nanoflowers with better control over morphology and high purity. 7,8 Morphological monitoring is not the only way to enhance photocatalytic activity. Doping and alloying prove as advanced methods to improve the catalyst's performance up to a substantial extent.…”

“…The exact growth mechanism has yet to be understood. In addition, the hydrothermal method is very promising for preparing MoS 2 nanoflowers with better control over morphology and high purity. , …”

Intermetallic molybdenum disilicide: a new, active, and stable cocatalyst for efficient solar hydrogen production

“…have been exploited to improve the efficiency of the photocatalytic HER in various systems. 1 c ,3,4 Among them, molybdenum (Mo)-based materials, including metallic Mo, 5 Mo-based alloys (NiMo), 6 sulfides (crystalline MoS 2 , amorphous MoS x , and molecule-like Mo–S clusters), 7 carbides (Mo 2 C), 8 nitrides (Mo 2 N), 9 phosphides (MoP), 10 borides (MoB x , x = 1, 4), 11 selenides (MoSe 2 ), 12 and so on, have shown great potential in replacing noble metal-based cocatalysts. Nevertheless, many of the above Mo-based cocatalysts are far away from the practical demands largely due to their insufficient activity and stability toward the photocatalytic HER.…”