Graphitic Carbon Nitride Nanoflakes Decorated on Multielement-Doped Carbon as Photocatalysts for Bacterial Disinfection under Visible and Near-Infrared Light

Abstract

Preparing photocatalyst-based graphitic carbon nitrides that have a broad active spectrum for energy and environmental applications remains a huge challenge. Sub-10-nm graphitic carbon nitride has become an attractive photocatalyst because of its impressive optical and electronic properties, strong quantum confinement, and an edge effect that converts near-infrared (NIR) into visible (vis). Herein, a photocatalyst with a broad active spectrum from vis (400−800 nm) to NIR (800−2500 nm) was prepared through the self-assembly of graphene-like graphitic carbon nitride nanoflakes decorated on multielement-doped carbon (g-C 3 N 4 NFC) for bacterial disinfection. The as-prepared g-C 3 N 4 NFC exhibited unique physical and chemical properties and a broad light absorption spectrum from the vis to NIR region. The g-C 3 N 4 NFC promoted high photocatalytic disinfection toward Escherichia coli and Staphylococcus aureus under vis and NIR exposure, while the conventional graphitic carbon nitride photocatalyst showed low catalytic activity and was not active under NIR radiation. The authors attribute this effect to the wide spectrum harvesting and inhibition of charge recombination caused by the ultrasmall size of g-C 3 N 4 NF and the introduction of multielement-doped carbon, respectively. The bactericidal mechanism occurred via the destruction of the cell membrane, which was confirmed by the leakage of intercellular cell components after direct contact with holes generated from photocatalytic activity on the catalyst surface in the presence of oxygen. The photocatalytic activity was essentially unchanged when the catalyst was reused five times, highlighting its excellent stability.

Stable Black Phosphorus Encapsulation in Porous Mesh-like UiO-66 Promoted Charge Transfer for Photocatalytic Oxidation of Toluene and o-Dichlorobenzene: Performance, Degradation Pathway, and Mechanism

“…Compared with the porous mesh-like structure present in the nanosheet material in BP–UiO (Figure S1A), BP/UiO shows an aggregation of conventional ortho-octahedra nanocrystals on the smooth surface of BP (Figure S1B), indicating the Zr–P bonds constructed by the crosslinking of Zr 4+ with BP is the key step for the formation of UiO-66 encapsulation layer. The formation of porous mesh-like morphology of BP–UiO facilitates the application in the photocatalytic degradation of toluene and o -dichlorobenzene as the open porous structure and is favorable for light-harvesting, charge separation, active site utilization, and more exposed interfacial contact with the reactants. − The previously reported UiO-66 has a similar ortho-octahedral structure, suggesting that the surface nanoparticles may be UiO-66, which needs further verification. HAADF-STEM image (Figure C) of BP demonstrates a similar morphology to the result of the SEM image.…”

Bridging Effect of Carbon Nitride with More Negative Conduction Potential and Halogens Promotes the Liquid-Phase Oxidation of Aromatic C–H Bonds

“…The UV–vis DRS spectra of all of the halogen and Ni-doped catalyst samples exhibited significant red shifts compared to pure CN, indicating significant improvements in their optical absorption capacities and an extension of CN’s optical response up to 800 nm. Among them, Br-CN displayed the best optical absorption capacity . This may be attributed to the presence of N vacancies and the formation of Ni surface traps that enhance the light reflection and optical absorption capacities.…”

“…Among them, Br-CN displayed the best optical absorption capacity. 38 This may be attributed to the presence of N vacancies and the formation of Ni surface traps that enhance the light reflection and optical absorption capacities. Furthermore, the doping of halogen and Ni expands the structural unit of CN, and the large three-dimensional spatial structure significantly influences light transfer efficiency inside the catalyst.…”

Enhancing the Fluorescence Activity of Graphitic Carbon Nitride Nanosheets by Eliminating the Active Defect States: Implications for Fluorescent Sensing and Biological Imaging

“…Graphitic carbon nitride (g-CN) is a kind of organic semiconductor that has a typical graphene-like two-dimensional (2D) structure. − Although it was proposed that the 2D framework of the material can be constructed of either triazine or tri- s -triazine, more and more recent evidence indicates that g-CN is mainly composed of tri- s -triazine rather than triazine. − g-CN has been a star material after the discovery of its photocatalytic hydrogen generation activity in 2009 . Besides its excellent photocatalytic activity, − g-CN also has fluorescence (FL) and electrochemiluminescence (ECL) properties that attract the broad attention of many analysts. − In particular, a large number of sensing and imaging systems have been constructed based on the FL properties of various g-CN-based materials. − …”