Toxic organic pollutants in the aquatic environment cause severe threats to both humans and the global environment. Thus, the development of robust strategies for detection and removal of these organic pollutants is essential. For this purpose, a multifunctional and recyclable membrane by intercalating gold nanoparticles and graphitic carbon nitride into graphene oxide (GNPs/g-C 3 N 4 / GO) is fabricated. The membranes exhibit not only superior surface enhanced Raman scattering (SERS) activity attributed to high preconcentration ability to analytes through π-π and electrostatic interactions, but also excellent catalytic activity due to the enhanced electron-hole separation efficiency. These outstanding properties allow the membrane to be used for highly sensitive detection of rhodamine 6G with a limit of detection of 5.0 × 10 −14 m and self-cleaning by photocatalytic degradation of the adsorbed analytes into inorganic small molecules, thus achieving recyclable SERS application. Furthermore, the excellent SERS activity of the membrane is demonstrated by detection of 4-chlorophenol at less than nanomolar level and no significant SERS or catalytic activity loss was observed when reusability is tested. These results suggest that the GNPs/g-C 3 N 4 /GO membrane provides a new strategy for eliminating traditional, single-use SERS substrates, and expands practical SERS application to simultaneous detection and removal of environmental pollutants.

Ammonium perchlorate (AP) is an oxidizer material that is widely employed in applications ranging from rocketry to airbags. Previous research has suggested that efficient electron transfer plays a critical role in determining the kinetics of catalyzed AP decomposition reactions. Consequently, intimate contact between AP crystals and electron acceptors has the potential to accelerate decomposition kinetics, which motivates the development of conformal coatings with suitably tailored electronic structures. Here, we demonstrate a scalable method for conformally coating AP crystals with two atomically well-defined 2D materials with orthogonal electronic propertiesnamely, pristine graphene, which is a zero-band gap semiconductor that has been shown to be an effective electron acceptor in diverse heterojunctions and hexagonal boron nitride (hBN), which is a wide-band gap electrical insulator. Consistent with an electron transfer mechanism, graphene-coated AP undergoes accelerated decomposition kinetics compared to uncoated (neat) or hBN-coated AP. Through extensive structural characterization including electron microscopy and X-ray diffraction, the effects of AP crystal size and crystallinity are examined. In addition, the accelerated decomposition kinetics of graphene-coated AP are quantified through thermogravimetric analysis, gas chromatography mass spectrometry, and kinetic modeling. Overall, this work establishes pristine graphene as an effective coating for promoting accelerated decomposition of AP, which enhances its utility in various applications.

Printed 2D materials, derived from solution‐processed inks, offer scalable and cost‐effective routes to mechanically flexible optoelectronics. With micrometer‐scale control and broad processing latitude, aerosol‐jet printing (AJP) is of particular interest for all‐printed circuits and systems. Here, AJP is utilized to achieve ultrahigh‐responsivity photodetectors consisting of well‐aligned, percolating networks of semiconducting MoS2 nanosheets and graphene electrodes on flexible polyimide substrates. Ultrathin (≈1.2 nm thick) and high‐aspect‐ratio (≈1 μm lateral size) MoS2 nanosheets are obtained by electrochemical intercalation followed by megasonic atomization during AJP, which not only aerosolizes the inks but also further exfoliates the nanosheets. The incorporation of the high‐boiling‐point solvent terpineol into the MoS2 ink is critical for achieving a highly aligned and flat thin‐film morphology following AJP as confirmed by grazing‐incidence wide‐angle X‐ray scattering and atomic force microscopy. Following AJP, curing is achieved with photonic annealing, which yields quasi‐ohmic contacts and photoactive channels with responsivities exceeding 103 A W−1 that outperform previously reported all‐printed visible‐light photodetectors by over three orders of magnitude. Megasonic exfoliation coupled with properly designed AJP ink formulations enables the superlative optoelectronic properties of ultrathin MoS2 nanosheets to be preserved and exploited for the scalable additive manufacturing of mechanically flexible optoelectronics.

Memristive systems present a low-power alternative to silicon-based electronics for neuromorphic and in-memory computation. 2D materials have been increasingly explored for memristive applications due to their novel biomimetic functions, ultrathin geometry for ultimate scaling limits, and potential for fabricating large-area, flexible, and printed neuromorphic devices. While the switching mechanism in memristors based on single 2D nanosheets is similar to conventional oxide memristors, the switching mechanism in nanosheet composite films is complicated by the interplay of multiple physical processes and the inaccessibility of the active area in a twoterminal vertical geometry. Here, the authors report thermally activated memristors fabricated from percolating networks of diverse solution-processed 2D semiconductors including MoS 2 , ReS 2 , WS 2 , and InSe. The mechanisms underlying threshold switching and negative differential resistance are elucidated by designing large-area lateral memristors that allow the direct observation of filament and dendrite formation using in situ spatially resolved optical, chemical, and thermal analyses. The high switching ratios (up to 10 3 ) that are achieved at low fields (≈4 kV cm −1 ) are explained by thermally assisted electrical discharge that preferentially occurs at the sharp edges of 2D nanosheets. Overall, this work establishes percolating networks of solutionprocessed 2D semiconductors as a platform for neuromorphic architectures.

α-RuCl 3 is a layered transition metal halide that possesses a range of exotic magnetic, optical, and electronic properties including fractional excitations indicative of a proximate Kitaev quantum spin liquid (QSL). While previous reports have explored these properties on idealized single crystals or mechanically exfoliated samples, the scalable production of α-RuCl 3 nanosheets has not yet been demonstrated. Here, we perform liquid-phase exfoliation (LPE) of α-RuCl 3 through an electrochemically assisted approach, which yields ultrathin, electron-doped α-RuCl 3 nanosheets that are then assembled into electrically conductive large-area thin films. The crystalline integrity of the α-RuCl 3 nanosheets following LPE is confirmed through a wide range of structural and chemical analyses. Moreover, the physical properties of the LPE α-RuCl 3 nanosheets are investigated through electrical, optical, and magnetic characterization methods, which reveal a structural phase transition at 230 K that is consistent with the onset of Kitaev paramagnetism in addition to an antiferromagnetic transition at 2.6 K. Intercalated ions from the electrochemical LPE protocol favorably alter the optical response of the α-RuCl 3 nanosheets, enabling large-area Mott insulator photodetectors that operate at telecommunications-relevant infrared wavelengths near 1.55 μm. These photodetectors show a linear photocurrent response as a function of incident power, which suggests negligible trap-mediated recombination or photothermal effects, ultimately resulting in a photoresponsivity of ≈2 mA/W.

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Shortages of personal protective equipment (PPE) at the start of the COVID-19 pandemic caused medical workers to reuse medical supplies such as N95 masks. While ultraviolet germicidal irradiation (UVGI) is commonly used for sterilization, UVGI can also damage the elastomeric components of N95 masks, preventing effective fit and thus weakening filtration efficacy. Although PPE shortage is no longer an acute issue, the development of sterilizable and reusable UV-resistant elastomers remains of high interest from a long-term sustainability and health perspective. Here, graphene nanosheets, produced by scalable and sustainable exfoliation of graphite in ethanol using the polymer ethyl cellulose (EC), are utilized as UV-resistant additives in polyurethane (PU) elastomer composites. By increasing the graphene/EC loading up to 1 wt %, substantial UV protection is imparted by the graphene nanosheets, which strongly absorb UV light and hence suppress photoinduced degradation of the PU matrix. Additionally, graphene/EC provides mechanical reinforcement, such as increasing Young’s modulus, elongation at break, and toughness, with negligible changes following UV exposure. These graphene/EC–PU composites remain mechanically robust over at least 150 sterilization cycles, enabling safe reuse following UVGI. Beyond N95 masks, these UVGI-compatible graphene/EC–PU composites have potential utility in other PPE applications to address the broader issue of single-use waste.

Ammonium perchlorate (AP) is commonly used in propulsion technology. Recent studies have demonstrated that two-dimensional (2D) nanomaterials such as graphene (Gr) and hexagonal boron nitride (hBN) dispersed with nitrocellulose (NC) can conformally coat the surface of AP particles and enhance the reactivity of AP. In this work, the effectiveness of ethyl cellulose (EC) as an alternative to NC was studied. Using a similar encapsulation procedure as in recent work, Gr and hBN dispersed with EC were used to synthesize the composite materials Gr–EC–AP and hBN–EC–AP. Additionally, EC was used because the polymer can be used to disperse other 2D nanomaterials, specifically molybdenum disulfide (MoS2), which has semiconducting properties. While Gr and hBN dispersed in EC had a minimal effect on the reactivity of AP, MoS2 dispersed in EC significantly enhanced the decomposition behavior of AP compared to the control and other 2D nanomaterials, as evidenced by a pronounced low-temperature decomposition event (LTD) centered at 300 °C and then complete high-temperature decomposition (HTD) below 400 °C. Moreover, thermogravimetric analysis (TGA) showed a 5% mass loss temperature (T d5%) of 291 °C for the MoS2-coated AP, which was 17 °C lower than the AP control. The kinetic parameters for the three encapsulated AP samples were calculated using the Kissinger equation and confirmed a lower activation energy pathway for the MoS2 (86 kJ/mol) composite compared to pure AP (137 kJ/mol). This unique behavior of MoS2 is likely due to enhanced oxidation–reduction of AP during the initial stages of the reaction via a transition metal-catalyzed pathway. Density functional theory (DFT) calculations showed that the interactions between AP and MoS2 were stronger than AP on the Gr or hBN surfaces. Overall, this study complements previous work on NC-wrapped AP composites and demonstrates the unique roles of the disperagent and 2D nanomaterial in tuning the thermal decomposition of AP.