Coproduction of hydrogen (H2) and hydrogen peroxide (H2O2) from water splitting is one of the most promising ways to alleviate the energy crisis and environmental pollution. Here, we first show the synthesis and photocatalytic property of an organic semiconductor (DAnTMS compound) from 9,10-dibromoanthracene and trimethylsilylacetylene. Then, a metal-free photocatalyst of a DAnTMS/carbon dot (DAnTMS/CD) composite was designed and fabricated, which achieved the efficient photocatalytic production of H2 and H2O2 without usage of any organic solvents and sacrificial agents. Under visible light, the DAnTMS/CD composite could produce H2O2 with a maximum rate of 396.7 μmol g-1 h-1 and H2 with a maximum rate of 265.0 μmol g-1 h-1 in pure water. Transient photovoltage tests showed that CDs changed the interfacial electron transfer kinetics and served as the active site for highly efficient H2 evolution. This work provided a deep insight into the function of CDs in regulating the catalytic property of organic photocatalysts.
Keywords: carbon dots; hydrogen; hydrogen peroxide; metal-free catalyst; organic photocatalysis; transient photovoltage.