Investigation on graphene and Pt co-modified CdS nanowires with enhanced photocatalytic hydrogen evolution activity under visible light irradiation

Abstract

Hydrogen evolution by photocatalytic water splitting has attracted extensive attention in recent years. Here we report a composite photocatalyst, in which graphene and Pt particles act as cocatalysts to modify CdS nanowires. This composite photocatalyst was prepared by a solvothermal method followed by a photoreduction process. The obtained samples were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and Brunauer-Emmett-Teller specific surface area analysis. The graphene and Pt comodified CdS nanowires gain a high hydrogen evolution rate of 3984 μmol h(-1) g(-1), which is almost 4 times higher than that of bare CdS nanowires and also higher than the sum of graphene-CdS and Pt-CdS nanowires. The obtained sample also exhibits a good stability. The encouraging results presented here can be attributed to the incorporation of graphene and Pt which show a synergetic effect for hydrogen evolution. This work paves a way to the potential application of CdS nanowires in energy conversion.

Graphene in Photocatalysis: A Review

“…It is generally believed that the co‐catalysts as traps can extract the energetic enough electrons and holes that migrate to the surface of the semiconductor without recombination, provide reaction active sites, stimulate the elctrocatalytic reduction and oxidation of the reactants adsorbed on their surface with the lowered overpotentials, and further decrease the activation energy for gas evolution . So far, various types of H 2 ‐evolution co‐catalysts, including noble metals/alloys (Pt, Au, Ag), graphene, earth‐abundant transition metals and their composites (e.g., Ni, MoS 2 , WS 2 , NiS x , CoS x , CoO x , Ni 2 P, NiO x , and Ni(OH) 2 ) have been available for different semiconductors, which generally exhibit very low electrochemical H 2 ‐evolution onset overpotentials (<−0.4 V). Meanwhile, the noble metal based oxides (e.g., RuO 2 , IrO x ), cost‐acceptable cobalt based species (e.g., CoO x , Co(II), Co(OH) 2 , Nocera Co–Pi), MnO x FeOOH, and NiOOH have been demonstrated to be excellent water‐oxidation co‐catalysts to boost the photocatalytic O 2 evolution over different semiconductors.…”

“…Another strategy is to load new active sites (co‐catalysts) onto the graphene supports. So far, various co‐catalysts such as Pt, plasmonic metals (Au, Ag, Bi, and Cu), alloy and earth‐abundant metal compounds (Ni, NiS x , NiO x , Ni(OH) 2 , WS 2 , MoS 2 , and nanoclusters) have been widely combined with graphene to construct highly effective hybrid co‐catalysts for photocatalytic hydrogen generation or CO 2 reduction, due to the perfect synergistic effect between these co‐catalysts and graphene. On the one hand, the increased active sites (co‐catalysts) can accelerate the utilization of collected photo‐generated electrons of graphene.…”

Efficient Photocatalytic Hydrogen Generation from Water over CdS Nanoparticles Confined Within an Alumina Matrix

“…Hydrogen (H 2 )a saclean and highly efficient fuel has received much attention. [1][2][3][4][5][6] Semiconductor-basedp hotocatalysis techniques, which can convert solar energy to hydrogen, have attracted increasingr esearch interest as ar esult of their great potentialt os olve the environmental and energy problems. [7][8][9][10][11] Many oxide-, oxynitride-, sulfide-, and oxysulfidebased photocatalystsh ave been developed to produce hydrogen from water under visible-light irradiation over the past few decades.…”

Nanocarbons with Different Dimensions as Noble-Metal-Free Co-Catalysts for Photocatalysts

“…CdS nanorods evenly spread on the surface of RGO nanosheets. RGO plays as an ideal platform for the nucleation and growth of CdS nanorods and has no obvious influence on the morphology of the CdS nanorods [99,100]. For photocatalytic reduction of CO2 to CH4, RGO/CdS nanocomposite photocatalysts with an optimal RGO content of 0.5 wt% exhibit the highest CH4-production rate of 2.51 mmol•h −1 g −1 , 10 times more than pure CdS nanorods, and even better than Pt-CdS composites.…”