TY - JOUR A1 - Quiroz, J. A1 - de Oliveira, P. F. M. A1 - Shetty, S. A1 - Oropeza, F. A1 - Peña O’Shea, V. A1 - Rodrigues, L. A1 - Rodrigues, M. A1 - Torresi, R. A1 - Emmerling, Franziska A1 - Camargo, P. T1 - Bringing earth-abundant plasmonic catalysis to light: Gram-scale mechanochemical synthesis and tuning of activity by dual excitation of antenna and reactor sites JF - ACS sustainable chemistry & engineering N2 - The localized surface plasmon resonance (LSPR) excitation in plasmonic nanoparticles (NPs) in the visible and near-infrared ranges is currently at the forefront of improving photocatalytic performances via plasmonic photocatalysis. One bottleneck of this field is that the NPs that often display the best optical properties in the visible and near-infrared ranges are based on expensive noble metals such as silver (Ag) and gold (Au). While earth-abundant plasmonic materials have been proposed together with catalytic metals in antenna–reactor systems, their performances remain limited by their optical properties. Importantly, the synthesis of plasmonic photocatalysts remains challenging in terms of scalability while often requiring several steps, high temperatures, and special conditions. Herein, we address these challenges by developing a one-pot, gram-scale, room-temperature synthesis of earth-abundant plasmonic photocatalysts while improving their activities beyond what has been dictated by the LSPR excitation of the plasmonic component. We describe the mechanochemical synthesis of earth-abundant plasmonic photocatalysts by using MoO3 (antenna) and Au (reactor) NPs as a proof-of-concept example and demonstrate that the dual plasmonic excitation of antenna and reactor sites enables the tuning of plasmonic photocatalytic performances toward the reductive coupling of nitrobenzene to azobenzene as a model reaction. In addition to providing a pathway to the facile and gram-scale synthesis of plasmonic photocatalysts, the results reported herein may open pathways to improved activities in plasmonic catalysis. KW - MoO3 KW - Au nanoparticles KW - Localized surface plasmon resonance KW - Plasmonic photocatalysis KW - Nitrobenzene reduction PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532089 DO - https://doi.org/10.1021/acssuschemeng.1c02063 VL - 9 IS - 29 SP - 9750 EP - 9760 PB - American Chemical Society CY - Washington, DC AN - OPUS4-53208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quiroz, V. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Saldabilita di lamiere in acciaio inossidabile austenico ed austeno-ferritico ad alto contenuto di manganese con processo laser JF - Rivista Italiana della Saldatura N2 - Manganese alloyed stainless steels represent a cost-effective alternative to conventional CrNi- stainless steels due to strong fl uctuations of the market prices for nickel seen during the last years. In CrMnNi steels, nickel is partially replaced by lower-cost manganese and small amounts of nitrogen for stabilization of the austenitic phase. This also brings benefi ts regarding the mechanical properties, as it results in an increased material strength. Laser beam welding of such materials was investigated for direct comparison with Standard CrNi steels. Main emphasis was laid on fi nding adequate process parameters to achieve a stable welding process and obtain a good weld quality. Two different laser sources, a 4.4 kW Nd:YAG and a 5 kW CO2 laser, were used to weld 1.5 mm stainless steel sheets in continuous wave mode. A high-Mn austenitic (1.4376) and a lean duplex (1.4162) steel, as well as the standard austenitic (1.4301) and duplex (1.4362) grades were selected as test materials. Both butt and lap joint confi gurations were studied. Experiments were carried out systematically, varying the welding speed, laser power and focal point position in order to determine adequate process windows. The infl uence of the shielding gas type and fl ow rate on the process stability and the weld quality were investigated. The effects of weld edge preparation on the weld appearance and quality levels attained were also examined. The obtained welded joints were subjected to radiographic tests for detection of internal imperfections. Also a metallurgical characterization of the samples regarding the resulting phase composition or balance and hardness depending on the welding process parameters was conducted. Furthermore, tensile and potentiodynamic tests were performed to evaluate the mechanical and corrosion properties, respectively. The results provide an insight into the advantages and limitations of the laser beam welding process for joining high-manganese alloyed stainless steels. Conditions for the production of defect-free and corrosion-resistant welds having good mechanical properties could be determined. KW - Weldability KW - Austenitic stainless steels KW - Corrosion KW - CO2 lasers KW - Duplex stainless steels KW - Laser welding KW - Manganese KW - Mechanical properties KW - Shielding gases KW - YAG lasers PY - 2016 SN - 0035-6794 VL - 68 IS - 1 SP - 33 EP - 43 AN - OPUS4-38100 LA - ita AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -