Upcycling of Wastewater via Effective Photocatalytic Hydrogen Production Using MnO(2) Nanoparticles—Decorated Activated Carbon Nanoflakes

In the present work, we demonstrated the upcycling technique of effective wastewater treatment via photocatalytic hydrogen production by using the nanocomposites of manganese oxide-decorated activated carbon (MnO(2)-AC). The nanocomposites were sonochemically synthesized in pure water by utilizing MnO(2) nanoparticles and AC nanoflakes that had been prepared through green routes using the extracts of Brassica oleracea and Azadirachta indica, respectively. MnO(2)-AC nanocomposites were confirmed to exist in the form of nanopebbles with a high specific surface area of ~109 m(2)/g. When using the MnO(2)-AC nanocomposites as a photocatalyst for the wastewater treatment, they exhibited highly efficient hydrogen production activity. Namely, the high hydrogen production rate (395 mL/h) was achieved when splitting the synthetic sulphide effluent (S(2−) = 0.2 M) via the photocatalytic reaction by using MnO(2)-AC. The results stand for the excellent energy-conversion capability of the MnO(2)-AC nanocomposites, particularly, for photocatalytic splitting of hydrogen from sulphide wastewater.