Sandeep Bose

All Publications

• Catalyst-Free Production of Urea from Nitrate and Carbon Dioxide in Water Microdroplets. Environmental science & technology Bose, S., Xu, J., Lee, K., Zare, R. N. 2025

  Abstract

  We report a simple, one-step selective process for producing urea (NH2CONH2) from nitrate (NO3-) dissolved in aqueous microdroplets when sprayed with carbon dioxide (CO2) as the nebulizing gas. This synthesis is accomplished without any catalyst or application of any external electric potential or radiation. The electric field at the gas-water interface is believed to drive the reaction process, resulting in urea being dissolved in the water microdroplets, which is the source of hydrogen for this conversion. The highest urea production rate of 118 muM h-1 is achieved with optimized parameters. The selectivity of urea formation in this process is >99%. Mass spectrometric studies were conducted to identify the reaction intermediates involved in the conversion. Density functional theory (DFT) calculations support our experimental observations by providing insights into the reaction pathways for the transformation. This eco-friendly approach for urea synthesis consumes CO2, thereby transforming a greenhouse gas into a value-added product.

  View details for DOI 10.1021/acs.est.5c01478

  View details for PubMedID 40415335

• Continuous Flow Contact Electrocatalysis for Hydrogen Peroxide Production JOURNAL OF PHYSICAL CHEMISTRY C Lee, K., Bose, S., Song, X., Choi, S. Q., Zare, R. N. 2025

  View details for DOI 10.1021/acs.jpcc.5c00163

  View details for Web of Science ID 001450111400001

• Sustainable Recovery of Rare Earth Metals from Smartphone Display using Nanoengineered Cellulose ADVANCED SUSTAINABLE SYSTEMS Bose, S., Ariya, P. A. 2024

  View details for DOI 10.1002/adsu.202400887

  View details for Web of Science ID 001370088500001

• Handheld portable device for delivering capped silver nanoparticles for antimicrobial applications. QRB discovery Naveen, K., Bose, S., Basheer, C., Zare, R. N., Gnanamani, E. 2024; 5: e9

  Abstract

  We describe a simple, cost-effective, green method for producing capped silver nanoparticles (Ag NPs) using a handheld portable mesh nebulizer. The precursor solution containing a 1:1 mixture of silver nitrate (AgNO3) and ligand (glycerol or sodium alginate) was sprayed using the nebulizer. The Ag NPs were generated in the water microdroplets within a few milliseconds under ambient conditions without any external reducing agent or action of a radiation source. The synthesized nanoparticles were characterized by using high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction analysis (XRD), which validated the formation of Ag NPs. The synthesized glycerate-capped silver nanoparticles (Ag-gly NPs) were used as a catalyst to show the oxidative coupling of aniline to form azobenzene products with a yield of up to 61%. Experiments conducted using Ag NPs produced in the droplets demonstrated more than 99% antibacterial activity when contacting Escherichia Coli. Our in-situ synthesis-cum-fabrication technique using a portable sprayer represents a viable alternative to the existing fiber or hydrogel-based antimicrobial wound healing.

  View details for DOI 10.1017/qrd.2024.9

  View details for PubMedID 39687232

  View details for PubMedCentralID PMC11649374

• Understanding the formation of nitrate from nitrogen at the interface of gas-water microbubbles. Chemical science Bose, S., Xia, Y., Zare, R. N. 2024

  Abstract

  Water microbubbles containing Fe2+ ions have been found to efficiently transform nitrogen (N2) to nitrate (NO3 -) by initiating Fenton's reaction at the gas-water interface. Herein, we elucidate the mechanism of the formation of nitrate (NO3 -) from nitrogen (N2) at the microbubble interface. Several experimental studies were conducted to identify the intermediates formed during the conversion. Our investigation shows the formation of H2N2O2, NO, NO2, and NO2 - intermediates before yielding NO3 - as the final product. Density functional theory (DFT) calculations provide additional support to our observation by providing insights into the energy profiles of the reaction intermediates. We believe that this work not only provides valuable insight into the abiotic nitrogen fixation in microbubbles but also helps in suggesting the modification of parameters to create a more reactive interface that leads to the enhanced production of nitric acid (HNO3).

  View details for DOI 10.1039/d4sc06989g

  View details for PubMedID 39568950

  View details for PubMedCentralID PMC11575618

• Direct Conversion of N2 and Air to Nitric Acid in Gas-Water Microbubbles. Journal of the American Chemical Society Bose, S., Mofidfar, M., Zare, R. N. 2024

  Abstract

  We report a simple, direct, and green conversion of air/N2 to nitric acid by bubbling the gas through an aqueous solution containing 50 μM Fe2+ ions. Air stone, along with ultrasonication, was employed to generate gas microbubbles. H2O2 produced at the water-gas interface undergoes Fenton's reaction with Fe2+ ions to produce OH• that efficiently activates N2, yielding nitric acid as the final product. Nitrate (NO3-) formation occurs without the use of any external electric potential or radiation. The concentration of NO3- increased linearly with time over a period of 132 h. The average NO3- production rate is found to be 12.9 ± 0.05 μM h-1. We envision that this nitrogen fixation strategy that produces nitric acid in an eco-friendly way might open the possibility for the energy-efficient and green production of nitric acid.

  View details for DOI 10.1021/jacs.4c11899

  View details for PubMedID 39315452