Mo-activated VC as effective cocatalyst for an enhanced photocatalytic hydrogen evolution activity of CdS

Seeking an efficient and stable cocatalyst is of importance for semiconductor-based photocatalytic water splitting to produce hydrogen. In this sense, Mo-activation of VC for better cocatalytic properties was proposed for the first time, aiming to attain improved hydrogen generation of CdS . Our novel, yet facile physical preparation method permits intimate coupling of Mo-activated VC cocatalyst to CdS (through electrostatic attraction force), thereby promises drastic activity enhancement for hydrogen generation. Results indicate the best VC-activating competency of Mo against other transition metals (Co, Fe, Ni, Zn and Cu), which induces highest H 2 productivity of CdS after modifying with Mo-activated VC. Under optimum setting, CdS/Mo(0.38)-VC(5 wt%) manifested highest photocatalytic hydrogen production rate of 2267 μmol h −1 g −1 , associated to 300 % and 440 % improvement as compared to that of CdS/VC(5 wt%) and pure CdS, respectively. Such activity also outperformed those that yielded by MoS x - or noble metals(Pt, Au or Ag)-co-catalyzed CdS, attributed to the promoted interfacial charges transfer and lowered overpotential of CdS/Mo(0.38)-VC(5 wt%) in hydrogen generation. Correspondingly, high apparent hydrogen production quantum efficiency of 4.3 % was also recorded by the same photocatalyst at 420 nm. In term of stability test, CdS/Mo(0.38)-VC(5 wt%) manifested excellent longevity in 24 h continuous photoreaction and fair recyclability over five consecutive photoreaction cycles. This work provides a new insight to cocatalysts design and synthesis, thereby realizing economic alternatives to precious metal (Pt, Au, Ag) in solar-derived H 2 production.