Nanomaterials with atleast one dimension not confined within nanoscale range are called 1D nanomaterials. We are working with palladium and palladium alloy nanowires synthesized using hydrothermal as well as three neck flask and tests their performance for hydrogen gas separation in a mixed matrix membrane. High aspect ratio palladium nanowires were synthesized using palladium chloride as a precursor and water as solvent. Branched palladium and palladium alloy nanowires were synthesized using polyol reduction of palladium nitrate salt and nitrate salts of other transition metals using PVP as reducing agent. nanowires We are also working on to try different application of these synthesized materials, like in hydrogen sensors or membrane reactor. 

Publications :

• Kumar, Abhishek, Mohammad Moein Mohammadi, and Mark T. Swihart. "Synthesis, growth mechanisms, and applications of palladium-based nanowires and other one-dimensional nanostructures." Nanoscale (2019). 

• Kumar, Abhishek, Liang Huang, Leiqing Hu, Deqiang Yin, Haiqing Lin, and Mark T. Swihart. "Facile One-Pot Synthesis of PdM (M= Ag, Ni, Cu, Y) Nanowires for use in Mixed Matrix Membranes for Efficient Hydrogen Separation." Journal of Materials Chemistry A (2021). 

• Kumar, A., Mohammadi, M.M., Zhao, Y., Liu, Y., Liu, J., Thundat, T. and Swihart, M.T., 2021. Reduced Graphene Oxide-Wrapped Palladium Nanowires Coated with a Layer of Zeolitic Imidazolate Framework-8 for Hydrogen Sensing. ACS Applied Nano Materials, 4(8), pp.8081-8093.

• Kumar, A., Thundat, T. and Swihart, M.T., 2022. Ultrathin Palladium Nanowires for Fast and Hysteresis-Free H2 Sensing. ACS Applied Nano Materials, 5(4), pp.5895-5905. .

• Kumar, A., Chen, K., Thundat, T. and Swihart, M.T., 2023. Based Hydrogen Sensors Using Ultrathin Palladium Nanowires. ACS Applied Materials & Interfaces. 

Here, a novel material for treating blown polypropylene filtration media used in medical‐grade masks to impart antimicrobial activity is reported. To produce thin copper@ZIF‐8 core‐shell nanowires (Cu@ZIF‐8 NWs), Cu NWs are stabilized using a pluronic F‐127 block copolymer, followed by growth of ZIF‐8 to obtain uniform core‐shell structures. The Cu@ZIF‐8 NWs are applied to filtration media by dip coating. Aerosol filtration efficiency decreases upon exposure to ethanol (solvent for dip‐coating), but increases with addition of Cu@ZIF‐8 NWs. Cu@ZIF‐8 NWs shows enhanced antibacterial activity, compared to Cu NWs or ZIF‐8 alone, against Streptococcus mutans and Escherichia coli. Antiviral activity against SARS‐CoV‐2 is assayed using virus‐infected Vero E6 cells, demonstrating 55% inhibition of virus replication after 48 h by 1 µg of Cu@ZIF‐8 NWs per well. Cu@ZIF‐8 NWs’ cytotoxicity is tested against four cell lines, and their effect on inflammatory response in A549 cells is examined, demonstrating good biocompatibility. 

Publications :

Kumar, Abhishek, Anu Sharma, Yi Chen, Megan M. Jones, Stephen T. Vanyo, Changning Li, Michelle B. Visser, Supriya D. Mahajan, Rakesh Kumar Sharma, and Mark T. Swihart. "Copper@ ZIF‐8 Core‐Shell Nanowires for Reusable Antimicrobial Face Masks." Advanced Functional Materials (2020): 2008054. 

Here, we demonstrate the design and fabrication of low-cost PdNS-based dual gas sensors for room-temperature detection of H2 and CO over a wide concentration range. We fabricated sensors using multiwalled carbon nanotube@PdNS (MWCNT@PdNS) composites and compared their performance against pure PdNS devices for hydrogen sensing based on electrical resistive response. Devices using PdNS alone had a response and response time of 0.4% and 50 s, respectively, to 1% H2 in air. MWCNT@PdNS (1:5 mass ratio) showed enhanced performance at a lower hydrogen concentration with a limit of detection (LODH2) of 5 ppm. Nearly an order of magnitude increase in response was observed on increasing the amount of MWCNT to 50 mass % in the nanocomposite, but the response fell off at low H2 concentration. Overall, these PdNS-based sensors were found to show good repeatability, stability, and performance under humid conditions. Their response was selective for H2 versus CH4, CO2, and NH3; the response to CO was comparable in magnitude but opposite in sign to the response to H2. Upon simultaneous exposure to equal concentrations (10 ppm each) of H2 and CO, the response to CO was dominant. The PdNS showed high sensitivity to CO, detecting as little as 1 ppm CO in air at room temperature. The sensitivity to CO could be used either in a stand-alone room-temperature CO detector, where H2 is known not to be present, or in combination with CO and combustible gas detectors to distinguish H2 from other combustible gases.

Publications :

• Kumar, Abhishek, Yaoli Zhao, Mohammad Moein Mohammadi, Jun Liu, Thomas Thundat, and Mark T. Swihart. "Palladium Nanosheet-Based Dual Gas Sensors for Sensitive Room-Temperature Hydrogen and Carbon Monoxide Detection." ACS sensors (2022).

• Kumar, A., Zhao, Y., Abraham, S.R., Thundat, T. and Swihart, M.T., 2022. Pd Alloy Nanosheet Inks for Inkjet‐Printable H2 Sensors on Paper. Advanced Materials Interfaces, 9(20), p.2200363.