@article {48756, title = {Mechanistic insights into near ambient pressure activity of intermetallic NiZn/TiO2 catalyst for CO2 conversion to methanol}, journal = {ChemCatChem}, volume = {15}, year = {2023}, month = {JAN }, type = {Article}, abstract = {

Ni-Zn pair is predicted through descriptor-based studies to be conducive for CO2 hydrogenation. In this study, NiZn (1 : 1) intermetallics supported on TiO2 is identified as a potential candidate for near ambient pressure activity. The effect of reduction temperature on the catalyst textural properties as well as on CO2 to methanol reduction are explored. Structural and microscopic studies provide clear evidence of phase evolution of NiZn alloy with increasing reduction temperatures, along with phase variations of Zn based oxides. Interface between NiZn intermetallics and ZnO nanoparticles observed at reduction temperature of 550 degrees C, seems to play a crucial role in making this system most active and selective to methanol. In addition, in-situ IR studies provide mechanistic insights and indicates the formation of methanolic species even at ambient pressure.

}, keywords = {CCUS, CO2, In-situ IR, Methanol, near ambient pressure}, issn = {1867-3880}, doi = {10.1002/cctc.202201150}, author = {Dongapure, Pavan and Tekawadia, Jyoti and Thundiyil, Shibin and Caha, Ihsan and Deepak, Francis Leonard and Devi, R. Nandini} } @article {49619, title = {Mimicking characteristics of cast iron for enhanced electrocatalytic dehydrogenation of methane}, journal = {Fuel}, volume = {381}, year = {2025}, month = {FEB}, pages = {133674}, type = {Article}, abstract = {

Enhancing the efficiency of methane dehydrogenation through chemical modification of electrocatalytic iron surfaces with impurities that resemble cast iron properties is demonstrated computationally using Density Functional Theory methodologies. Investigating methane dehydrogenation on thermally stable Fe surfaces with discrete planes and anchoring impurities such as Al, C, and Si minimized reduction barriers. Electrochemical treatment of methane on these robust surfaces yields clean hydrogen and carbon-based compounds, such as carbon nanomaterials and carbon black. As for the most efficient active sites for enhanced methane dehydrogenation, the active plane 100 with 5.5 \% C impurities and 0.51 eV reduction barrier is determined to be the most dependable, followed by the active plane 110 with 5.5 \% Si impurities and the lower 0.98 eV reduction barrier. Utilizing CI-NEB (Nudged Elastic Band), the dissociation barrier investigation established the electrolytic catalysts{\textquoteright} performance. This work paves the way for experimentalists and demonstrates the economic viability of Fe-based catalysts for the Catalytic Dehydrogenation of Methane.

}, keywords = {carbon black, Density Functional Theory (DFT), Dry methane reforming (DMR), Electrochemical methane dehydrogenation, Fe surface catalyst}, issn = {0016-2361}, doi = {10.1016/j.fuel.2024.133674}, author = {Verma, Tushar Singh and Devi, R. Nandini and Krishnamurty, Sailaja} } @article {49975, title = {Modulation in surface properties by Ni doping in Na2Ti3O7: effect on dry reforming of methane}, journal = {ACS Applied Engineering Materials}, volume = {3}, year = {2025}, month = {MAY}, pages = {1503{\textendash}1512}, type = {Article}, abstract = {

Dry reforming of CH4\ using CO2\ is considered as an excellent process for converting two greenhouse gases to platform chemicals. However, the challenge is severe coking as well as sintering and consequent deactivation in the absence of steam as in the more prevalent steam reforming. Here, we present a layered Ti-based oxide with appropriate basicity to facilitate CO2\ adsorption and active metal Ni incorporated in the lattice sites to minimize sintering. Ni-doped Na2Ti3O7\ was synthesized using the sol{\textendash}gel method and subsequently characterized and screened in dry reforming of methane. Characterization results indicate the successful formation of the monoclinic phase of Na2Ti3O7. The variant Na2Ni0.2Ti2.8O7, which contains a higher concentration of Ni, exhibited improved reducibility and basicity, as determined through H2-TPR and CO2-TPD analysis. The presence of hydroxide, carbonate, and bicarbonate species was confirmed via X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transformation (DRIFT) studies, leading to increased conversion of CH4\ and CO2\ over extended periods with the Na2Ti2.8Ni0.2O7\ catalyst. Basic Ti{\textendash}OH groups replenished under reaction conditions may play a vital role in reducing coke formation in this catalyst. Post-reaction characterization revealed phase transformations in low Ni content catalysts, as evidenced by X-ray diffraction (XRD) and RAMAN analysis. Additionally, the suppression of coke formation and morphological changes were assessed through thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM) analyses in Na2Ti2.8Ni0.2O7\ catalyst, respectively. The study highlighted the significant influence of elevated Ni concentrations on phase stability and conversion efficiency in the dry reforming of methane. This also evidences the importance of defects created by appropriate doping, which modulates the surface properties facilitating coke gasification.

}, doi = {https://doi.org/10.1021/acsaenm.5c00025}, author = {Ghodke, Seema R. and Devi, R. Nandini} }