Rational utilization of highly conductive, commercial Elicarb graphene to advance the graphene-semiconductor composite photocatalysis

Highly conductive commercial Elicarb graphene (EGR) has been used to synthesize graphene-semiconductor CdS composite photocatalysts with distinctly enhanced visible light activity. The improved electron conductivity of EGR as compared to reduced graphene oxide (RGO) results in the enhancement of separation and transfer of photogenerated charge carriers. [Display omitted] •Highly conductive commercial Elicarb graphene (EGR) is used rationally.•The low solution processability of EGR is resolved.•Intimate interfacial contact for CdS-graphene composite photocatalysts is achieved.•The effect of graphene conductivity on improving CdS photoactivity is studied. Graphene oxide (GO) has widely been used as the precursor of graphene to construct graphene-semiconductor composite photocatalysts for various redox reactions. However, the electrical conductivity and charge carrier mobility of reduced GO (RGO) are remarkably decreased due to considerable disruption of the 2D π-conjugation of the electronic structure in the domain of RGO sheets, which results that the net improvement efficiency of photoactivity is often limited. Herein, we report a simple yet efficient strategy of rational utilization of highly conductive, commercial Elicarb graphene (EGR), which is manufactured on a large scale via a high-shear exfoliation process in liquid phase, to synthesize EGR-semiconductor CdS composite photocatalysts with distinctly enhanced activity as compared to RGO-CdS counterparts for photocatalytic hydrogen evolution under visible light illumination. To resolve the low solution processability deficiency of EGR, we select the surfactant, sodium dodecyl benzene acid (SDBS), to functionalize the surface of EGR with additional hydrophilic functional groups, thereby making SDBS-modified EGR well dispersed in aqueous phase and negatively charged. In addition, the hybridization of CdS with graphene via the electrostatic self-assembly strategy guarantees the intimate interfacial contact. This conceptual study would spur further interest in virtuous interactive loop between fundamental research and commercialization of graphene materials to advance graphene-semiconductor composite photocatalysis.