@article {48699, title = {Ferroelectric polarization and iron substitution synergistically boost electrocatalytic oxygen evolution reaction in bismuth oxychloride nanosheets}, journal = {Langmuir}, volume = {39}, year = {2023}, month = {AUG }, pages = {11414-11425}, type = {Article}, abstract = {

Ferroelectric materials have gained significant interestin variouskinds of water splitting, but the study of ferroelectric materialsfor electrocatalytic water splitting is in its infancy. Ferroelectricmaterials have spontaneous polarization below their Curie temperaturedue to dipolar alignment, which results in surface charges. In 2Dferroelectric materials, spontaneous polarization depends on thickness.Herein, we report that thickness-dependent ferroelectric polarizationin 2D nanosheets can also accelerate the oxygen evolution reaction(OER) along with the tailored active surface area of exposed crystallinefacets, which improves the electrocatalytic activity relatively. Iron-substitutedBiOCl nanosheets of varying thickness are fabricated by varying thepH using a facile coprecipitation method. The substituted iron enhancespolarization and electrochemical active sites on the surface. Thefindings in this study show that the exposed (001) facet and higherthickness of the nanosheets have high ferroelectric polarization and,in turn, superior electrocatalytic activity and remarkable stability,requiring low overpotentials (348 mV and 270 mV at 100 mA/cm(2) and 10 mA/cm(2)) in alkaline (1.0 M KOH) electrolyte. Asthe thickness of the nanosheets is decreased from 140 to 34 nm, theelectrocatalytic performance of iron-substituted BiOCl nanosheetsstarts to reduce due to the lower Coulomb-Coulomb interactionand the increasing depolarization.

}, issn = {0743-7463}, doi = {10.1021/acs.langmuir.3c01272}, author = {Singh, Dinesh and Joshi, Bhavana and Poddar, Pankaj} } @article {48683, title = {Scalable synthesis of dodecanethiol-capped bismuth nanoparticles by a solvent-free solid-state grinding method for reduction of 4-nitrophenol to 4-aminophenol}, journal = {Langmuir}, volume = {39}, year = {2023}, month = {Aug}, pages = {11888-11897}, type = {Article}, abstract = {

Thiol-capped metal nanoparticles have two constituents:an inorganicmetal and an organic molecule as a shell. Both characters are inbuiltin the structure of the metal thiolate. Herein, we have investigatedbismuth dodecanethiolate as a precursor for the synthesis of dodecanethiol-cappedbismuth nanoparticles (Bi NPs) by a solid-state grinding method. Byusing sodium borohydride and bismuth dodecanethiolate, crystallinebismuth nanoparticles are synthesized in a solvent-free environmentat room temperature (24 \& PLUSMN; 4 \& DEG;C). Bi NPs are tested for catalyticactivity by reducing 4-nitrophenol (4-NP) to 4-aminophenol (4-AP)with an excess of NaBH4. Dodecanethiol-capped bismuth nanoparticlesexhibit an efficient reduction of 4-NP to 4-AP within 12 min. Additionally,these nanoparticles remain catalytically active for up to three cycles.

}, issn = {0743-7463}, doi = {10.1021/acs.langmuir.3c01694}, author = {Singh, Dinesh and Poddar, Pankaj} } @article {49045, title = {In situ synthesis of metal (Bi0)-semiconductor [BiOX (X = Cl, Br, and I)] nanocomposites as a highly effective catalyst for the reduction of 4-nitrophenol to 4-aminophenol}, journal = {New Journal of Chemistry }, volume = {48}, year = {2024}, month = {MAY }, pages = {9840-9855}, type = {Article}, abstract = {

The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) has been efficiently catalyzed by in situ generated Bi-0-BiOX (X = Cl, Br, I) nanocomposites in the presence of sodium borohydride (NaBH4). The hierarchical 3D arrays of precursors (BiOCl, BiOBr, and BiOI) have been synthesized by a facile co-precipitation method at ambient temperature. The metallic Bi-0 is generated in situ by partial reduction of the Bi3+ ions in BiOX (X = Cl, Br, and I) mediated by NaBH4 during the conversion of 4-NP to 4-AP. In situ generated Bi-0-BiOX shows better catalytic activity than Bi-0-BiOX composite formed by mixing individually synthesized metallic Bi-0 particles with semiconducting BiOX nanoparticles. The Bi-0-BiOI nanocomposite demonstrated higher catalytic activity (k(app) = 0.529 min(-1)) compared to Bi-0-BiOCl (k(app) = 0.095 min(-1)) and Bi-0-BiOBr (k(app) = 0.098 min(-1)) due to its efficient conversion into metallic Bi-0. The approximate percentage composition of in situ generated metallic Bi-0 on the surface of BiOCl, BiOBr, and BiOI is nearly 10, 17, and 25\%, respectively. Further, the reduction of 4-NP has been completed within 24, 22, and 6 minutes by in situ generated Bi-0-BiOCl, Bi-0-BiOBr, and Bi-0-BiOI nanocomposites from BiOCl, BiOBr, and BiOI, respectively. Extensive studies have been conducted to generate a better understanding of the actual catalytic sites present on the surface of the catalysts.

}, issn = {1144-0546}, doi = {10.1039/d4nj01126k}, author = {Singh, Dinesh and Poddar, Pankaj} }