Upcycling of Wastewater via Effective Photocatalytic Hydrogen Production Using MnO2 Nanoparticles—Decorated Activated Carbon Nanoflakes

Abstract

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 (MnO2-AC). The nanocomposites were sonochemically synthesized in pure water by utilizing MnO2 nanoparticles and AC nanoflakes that had been prepared through green routes using the extracts of Brassica oleracea and Azadirachta indica, respectively. MnO2-AC nanocomposites were confirmed to exist in the form of nanopebbles with a high specific surface area of ~109 m2/g. When using the MnO2-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 (S2− = 0.2 M) via the photocatalytic reaction by using MnO2-AC. The results stand for the excellent energy-conversion capability of the MnO2-AC nanocomposites, particularly, for photocatalytic splitting of hydrogen from sulphide wastewater.

Excellent Electrocatalytic Hydrogen Evolution Reaction Performances of Partially Graphitized Activated-Carbon Nanobundles Derived from Biomass Human Hair Wastes

“…The graphitization of AC would strongly affect the porosity of the entire material system because the local recrystallization at the high temperature gives rise to the increase in structural faults and voids at both the crystallite interfaces and the grain boundaries inside the partially crystallized solid-state material system (i.e., polycrystalline-amorphous mixture) [ 31 , 37 ]. To verify such a hypothesis, the textural properties were assessed through the BET and the BJH methods.…”

One-Pot Synthesized Biomass C-Si Nanocomposites as an Anodic Material for High-Performance Sodium-Ion Battery

“…From the Raman scattering spectroscopy measurement, the sample also revealed its intrinsic vibration properties from only Si and C. As displayed in Figure 2b, the sample showed the four predominant Raman bands at 514, 959, 1341, and 1590 cm −1 from Si and C. The former two bands at 514 and 959 cm −1 originate from the first and the second order transversal optical (TO) mode of crystalline Si [58,59], respectively; and the latter two vibration modes at 1341 and 1590 cm −1 come from D (sp 3 type) and G (sp 2 type) bands of graphitized C, respectively [60,61]. Here, it should be noticeable that the C nanoflakes exhibited the high intensity area ratio of ID/IG (i.e., Asp 3 /Asp 2 ≅ 0.99), indicative of the high graphitization (i.e., ultrathin C layers) and large amount of sp 2 carbon exists in the composite system [39,53,60,[62][63][64]. The absence of extra lattice phases and their vibrations depict that the high purity C-Si nanocomposites were well-crystallized with their intrinsic carbonaceous and siliceous resources via the one-pot synthesis of magnesiothermic reduction using biomass BRH ashes.…”

Recent advancement of biomass-derived porous carbon based materials for energy and environmental remediation applications

“…The result was credited to the high conductivity and porosity of the nanocomposite system. 368 A pioneering work of Wang et al…”

“…The result was credited to the high conductivity and porosity of the nanocomposite system. 368 A pioneering work of Wang et al worth mentioning is the design of porous graphene nanosheets (PGS) through gas-exfoliation and KOH activation processes performed on Plumeria rubra . The resultant material possessed a hierarchical structure, ultra-high specific surface (1581 m 2 g −1 ) and high pore volume (0.916 cm 3 g −1 ).…”