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.
From our users
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.
From our users
Adv. Func. Mater., 30, 1906556, (2019)
PdTe2 Transition-Metal Dichalcogenide: Chemical Reactivity, Thermal Stability, and Device Implementation
G. D'Olimpio, C. Guo, C.N. Kuo, R. Edla, C.S. Lue, L. Ottaviano, P. Torelli, L. Wang, D.W. Boukhvalov, A. Politano
Palladium ditelluride (PdTe2) is a novel transition‐metal dichalcogenide exhibiting type‐II Dirac fermions and topological superconductivity. To assess its potential in technology, its chemical and thermal stability is investigated by means of surface‐science techniques, complemented by density functional theory, with successive implementation in electronics, specifically in a millimeter‐wave receiver. While water adsorption is energetically unfavorable at room temperature, due to a differential Gibbs free energy of ≈+12 kJ mol−1, the presence of Te vacancies makes PdTe2 surfaces unstable toward surface oxidation with the emergence of a TeO2 skin, whose thickness remains sub‐nanometric even after one year in air. Correspondingly, the measured photocurrent of PdTe2‐based optoelectronic devices shows negligible changes (below 4%) in a timescale of one month, thus excluding the need of encapsulation in the nanofabrication process. Remarkably, the responsivity of a PdTe2‐based millimeter‐wave receiver is 13 and 21 times higher than similar devices based on black phosphorus and graphene in the same operational conditions, respectively. It is also discovered that pristine PdTe2 is thermally stable in a temperature range extending even above 500 K, thus paving the way toward PdTe2‐based high‐temperature electronics. Finally, it is shown that the TeO2 skin, formed upon air exposure, can be removed by thermal reduction via heating in vacuum.
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and managed by the Commissione NFFA chaired by Giorgio Rossi
(Università di Milano and IOM-CNR).