NiO-nanoflakes grafted graphene: an excellent photocatalyst and a novel nanomaterial for achieving complete pathogen control

Abstract

The increased levels of industrial pollutants in water and of drug-resistant pathogens more generally are a serious threat to human and aquatic life. Herein, we present the solar-light-induced dye removal and bactericidal properties of nickel oxide (NiO) and graphene nanoplatelet (GNP) nanocomposites. The conducting nature of GNPs is the key factor that accounts for the enhanced photocatalytic and antibacterial activity. Remarkably, the graphene/NiO nanocomposite shows outstanding photocatalytic activity (99% degradation) as compared to NiO (34%) alone, which makes it a potential candidate for the depollution of dye-contaminated water. In addition, the optimized amount of GNPs in the graphene/NiO nanocomposite renders it an exceptional antibacterial material, producing 100% growth inhibition of pathogenic microorganisms (both Gram-positive and Gram-negative bacteria). Therefore, the graphene/NiO nanocomposite can be an innovative material to achieve complete pathogen control, alongside being an economic solution for water treatment.

Two‐Dimensional Materials for Antimicrobial Applications: Graphene Materials and Beyond

“…GMs have been combined with metal/metal oxide nanoparticles, such as AgNPs, [62][63][64][65][66][67][68][69][70][71][72] CuNPs, [73][74][75][76] Au nanostructures, [77À79] alloy NPs, [80,81] TiO 2 NPs, [82][83][84][85][86][87][88] ZnO NPs, [89][90][91][92] Fe 3 O 4 NPs, [93][94][95][96][97][98] CuO nanostractures, [99][100][101][102] SnO 2 NPs, [103] NiO NPs, [104] CeO 2 NPs, [105] and WO 3 NPs, [106] to form GM-metal nanohybrids. Some repre-sentativeG M-metaln anohybrids and their advantages are summarized in Ta ble 1.…”

Nickel Oxide/Graphene Composites: Synthesis and Applications

“…Sharma and Lee utilized NiO/rGO to remove organic o ‐chlorophenol, and Arshad et al. utilized NiO/graphene to photodegrade Methyl Orange under visible‐light irradiation . Figure a shows the mechanism of a graphene/NiO photocatalyst for degrading Methyl Orange.…”

“…Moreover, NiO/graphene photocatalysts can also be applied to disinfection. A NiO/graphene composite designed by the group of Arshad exhibited 100 % growth inhibition of pathogenic microorganisms . Charge transfer between NiO/graphene and the bacterial membranes leads to a charge imbalance and results in bacterial death (Figure b).…”

“…TiO 2 /NiO heterostructures with p-n junctions could establish an internal electrical field, leading to adecreasei nthe recombination rate and enhancement of the photocatalytic efficiency. [141,142] However,t he inclusion of graphene could be am ore economical solution for several reasons: [143,144] First, the large surfacearea provides numerous sites for the adsorptiono fN iO. Second, the band gap of NiO could be made narrower.T hird, due to its intrinsic conductivity,e lectrons can easily transfer from NiO to graphene.…”

“…utilized NiO/graphene to photodegrade Methyl Orange under visible-light irradiation. [144] Figure 9a shows the mechanism of ag raphene/NiO photocatalyst for degrading Methyl Orange. Once the dye molecule is absorbedo nto the surfaceo ft he NiO/graphene composite, the electron-hole pair generates reactive oxygen, which alters the ring structure of Methyl Orange.…”