Raju Edla worked as a CNR-IOM Post-doc from April 2017 to Decembre 2019.
He is currently working at the Karlsruhe Institute of Technology, Germany.
His research was focused on “Design and development of in-situ reaction cell at APE-HE Beam line” for XAS measurements in ambient pressure. Research work carried out on deposition of various thin film catalysts by PLD, sputtering and chemical techniques for energy and environmental applications such as Photocatalysis for water treatment, Electrochemical water splitting, CO oxidation and H2 generation from hydrolysis of complex hydrides.
The redox process of pretreated Co3O4 thin film coatings has been studied by ambient pressure soft X-ray absorption spectroscopy. The Co3O4 coatings were composed of nanoparticles of about 10 nm in size as prepared by pulsed laser deposition. The thin film coatings were pretreated in He or in H2 up to 150 °C prior to exposure to the reactive gases. The reactivity toward carbon monoxide and oxygen was monitored by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy during gas exposures. The results indicate that the samples pretreated in He show reactivity only at high temperature, while the samples pretreated in H2 are reactive also at room temperature. X-ray photoemission spectroscopy measurements in ultra-high vacuum and NEXAFS simulations with the CTM4XAS code further specify the results.
Phys. Status solidi RRL, 1900332, (2019)
Interaction of VSe2 with Ambient Gases: Stability and Chemical Reactivity
R. Edla, C.N. Kuo, P. Torelli, C.S. Lue, D.W. Boukhvalov, Antonio Politano
Combining first‐principles calculations with synchrotron‐based X‐ray photoelectron spectroscopy, the surface chemical reactivity of VSe2 single crystals toward oxygen, water, and air is assessed. It is found that the pristine, undefected surface is inert toward oxygen and water adsorption. The presence of Se defects drastically changes the surface reactivity. Specifically, water adsorption at room temperature is dissociative and mainly localized at Se vacancies. In contrast, surface oxidation is achieved only after long‐term air exposure (1 month). These results are crucial to assess the surface stability in ambient environment in the prospect of VSe2‐based applications.
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Adv. Funct. Mater., 29, 1900438, (2019)
Surface Instability and Chemical Reactivity of ZrSiS and ZrSiSe Nodal‐Line Semimetals
D.W. Boukhvalov, R. Edla, A. Cupolillo, V. Fabio, R. Sankar, Y. Zhu, Z. Mao, J. Hu, P. Torelli, G. Chiarello, L. Ottaviano, A. Politano
Materials exhibiting nodal‐line fermions promise superb impact on technology for the prospect of dissipationless spintronic devices. Among nodal‐line semimetals, the ZrSiX (X = S, Se, Te) class is the most suitable candidate for such applications. However, the surface chemical reactivity of ZrSiS and ZrSiSe has not been explored yet. Here, by combining different surface‐science tools and density functional theory, it is demonstrated that the formation of ZrSiS and ZrSiSe surfaces by cleavage is accompanied by the washing up of the exotic topological bands, giving rise to the nodal line. Moreover, while the ZrSiS has a termination layer with both Zr and S atoms, in the ZrSiSe surface, reconstruction occurs with the appearance of Si surface atoms, which is particularly prone to oxidation. It is demonstrated that the chemical activity of ZrSiX compounds is mostly determined by the interaction of the Si layer with the ZrX sublayer. A suitable encapsulation for ZrSiX should not only preserve their surfaces from interaction with oxidative species, but also provide a saturation of dangling bonds with minimal distortion of the surface.
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