Metal Sulfide/Gaphene Nanocomposites: Room-temperature Solid Phase Synthesis And Photocatalytic H₂Production Activity

The energy shortage and environmental pollution are two main topics ofscientific research in the21th century. In the current society, with the exponentialgrowth of demand for traditional fossil fuels, it seems be short supplied, on the otherhand, the large consumption of fossil suels causes greenhouse growing. To achievesustainable development, low energy consumption, low pollution based “low carboneconomy” is becoming a hotspot of global research. With the depth scientific research,hydrogen also known for its pollution-free, high calorific value, convenient storageand other advantages, all these will be seen as the best alternative energy source. Ithas been found that the photocatalytic reaction also has many advantages like nosecondary pollution, mild conditions, complete degradation of organic matters.Therefore, the semiconductor photocatalytic hydrogen production is in a widespreadconcern.In this paper, we proposed a facile approach for fabrication of the CdS/graphenenanocomposites via low-temperature solid phase reaction in one step. Themorphology, microstructure were characterized by the X-ray diffraction (XRD),transmission electron microscopy (TEM), Fourier transform infrared spectrum(FT-IR), ultraviolet–visible (UV–vis) spectroscopy and photocatalytic H2productionactivity under visible light. The results show that the graphene in the compositematerials prevents CdS agglomeration effectively, increase its specific surface areaand an amount of graphene can increase the catalytic activity of the complex. Theoptimal weight percentage of graphene was found to be2wt%, which resulted in avisible-light photocatalytic H2-production rate of1.096mmol·h-1with0.5wt%Pt as acocatalyst and triethanolamine as a sacrificial agent. It demonstrate that the uniquefeatures of graphene can not only improve the dispersion of CdS nanoparticles, butalso accelerate the migration of photogenerated charges, improve the catalytic activityand light stability of the composite materials as a good carrier for semiconductornanomaterials. This work highlights more generally the potential application ofgraphene based materials in the field of energy conversion, especially in the photocatalytic hydrogen production.On the basis, we adopted a method that dopes negative (positive) ion into theCdS/graphene composites for modify, the catalyst is prepared to do the followingcharacterization and testing. The morphology, microstructure were characterized bythe X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV–vis) spectroscopy and photocatalytic H2production activity undervisible light. The results showed that the catalyzed hydrolysis hydrogen rate of thepositive ions Zn2+doped composites has increased slightly, however, the respectiveproperties of the negative Cl-and Br-doped CdS/graphene composites are weakened.Therefore, appropriate doping positive ions can broaden the response light range ofcomposite materials, improve the photocatalytic hydrogen production efficiency ofthe composite materials, which also provides a new way to synthesis more complexCdS/graphene composite materials in the future.