TY - JOUR A1 - Pavlidis, Sotirios A1 - Fischer, Eric W. A1 - Opis-Basilio, Amanda A1 - Bera, Ayan A1 - Guilherme Buzanich, Ana A1 - Álvarez-Sánchez, María A1 - Wittek, Severin A1 - Emmerling, Franziska A1 - Ray, Kallol A1 - Roemelt, Michael A1 - Abbenseth, Josh T1 - Ambiphilic Reactivity and Switchable Methyl Transfer at a T-Shaped Bi(NNN) Complex Enabled by a Redox-Active Pincer Ligand N2 - We report the transition-metal-like reactivity of a geometrically constrained, ambiphilic bismuth(III) trisamide. Planarization of the Bi(III) center unlocks Bi−C bond formation when reacted with mild electrophiles (alkyl iodides and triflates) accompanied by two-electron oxidation of the utilized NNN pincer nligand. The preservation of the bismuth oxidation state is confirmed by single-crystal X-ray diffraction and X-ray absorption spectroscopy and corroborated by theoretical calculations. Sequential reduction of the oxidized ligand framework alters the reactivity of a generated Bi−Me unit, enabling controlled access to methyl cation, radical, and anion equivalents. The full [Bi(Me)(NNN)]+/•/− redox series was comprehensively characterized using NMR and EPR spectroscopy as well as spectro-electrochemistry. This work represents the first example of ligand-assisted, redox-neutral C−X bond splitting at bismuth, establishing a new paradigm for synthetic bismuth chemistry. KW - Pincer ligand KW - XAS KW - Redox PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654948 DO - https://doi.org/10.1021/jacs.5c18955 SN - 0002-7863 VL - 148 IS - 2 SP - 2683 EP - 2692 PB - American Chemical Society (ACS) AN - OPUS4-65494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yao, Xingyu A1 - Antunes, Margarida M. A1 - Guilherme Buzanich, Ana A1 - Cabanelas, Pedro A1 - Valente, Anabela A. A1 - Pinna, Nicola A1 - Russo, Patrícia A. T1 - Formation, Phase Transition, Surface, and Catalytic Properties of Cubic ZrO 2 Nanocrystals N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-Performance sodium storage anode. The presence of iron triggers the loss of long-rangeorder through disorder of the FeO6 octahedra local structure, subsequentlyallowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites forpseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation. KW - XAS KW - Sodium-ion Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654955 DO - https://doi.org/10.1021/acs.chemmater.5c01483 SN - 0897-4756 VL - 37 IS - 21 SP - 8568 EP - 8580 PB - American Chemical Society (ACS) AN - OPUS4-65495 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, Yanchen A1 - Guilherme Buzanich, Ana A1 - Alippi, Paola A1 - Montoro, Luciano A. A1 - Lee, Kug‐Seung A1 - Jeon, Taeyeol A1 - Weißer, Kilian A1 - Karlsen, Martin A. A1 - Russo, Patrícia A. A1 - Pinna, Nicola T1 - FeNb 2 O 6 as a High‐Performance Anode for Sodium‐Ion Batteries Enabled by Structural Amorphization Coupled with NbO 6 Local Ordering N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-performance sodium storage anode. The presence of iron triggers the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation. KW - SIB KW - XAS KW - Sodium-ion Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654931 DO - https://doi.org/10.1002/adma.202504100 SN - 0935-9648 VL - 37 IS - 46 SP - 1 EP - 13 PB - Wiley AN - OPUS4-65493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faustino, Leandro A. A1 - de Angelis, Leonardo D. A1 - de Melo, Eduardo C. A1 - Farias, Giliandro A1 - dos Santos, Egon C. A1 - Miranda, Caetano R. A1 - Buzanich, Ana G. A1 - Torresi, Roberto M. A1 - de Oliveira, Paulo F.M. A1 - Córdoba de Torresi, Susana I. T1 - Urea synthesis by Plasmon-Assisted N2 and CO2 co-electrolysis onto heterojunctions decorated with silver nanoparticles N2 - The N2 + CO2 co-electrolysis to urea synthesis has become a promising alternative to the energy intensive traditional processes for urea production. However, there are still challenges in this approach, especially due to the competition with HER (Hydrogen Evolution Reaction) leading to low efficiency. Electrochemistry assisted by localized surface plasmon resonance (LSPR) using metal nanoparticles has been reported to enhance different electrochemical reactions. Here we report an electrochemical LSPR assisted urea synthesis using Ag nanoparticles (NPs) supported on BiVO4/BiFeO3 catalyst mechanochemically synthesized. The electrochemical experiments were performed under dark and upon plasmon excitation at the LSPR region of Ag NPs. Our results demonstrated that exciting in the LSPR range, urea yield rate and Faradic efficiency were considerably improved with reduced overpotential, 19.2 μmol h− 1 g− 1 and FE 24.4% at +0.1 V vs RHE compared to 9.6 μmol h− 1 g− 1 and FE 9.4% at − 0.2 V vs RHE under dark conditions. Further in situ FTIR-RAS experiments for mechanism investigation revealed the presence of N-H and C-N intermediates and the real effect of Ag plasmon excitation on HER and N2 + CO2 co-electrolysis. Theoretical calculations confirm the energy of the species involved in C-N coupling as well the role of the complex catalytic sites, which agrees with XAS measurements. KW - Plasmon-assited KW - XAS KW - Urea KW - Electrocatalysis PY - 2025 DO - https://doi.org/10.1016/j.cej.2025.163072 SN - 1385-8947 VL - 513 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-65492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gomes, Bruna F. A1 - Prokop, Martin A1 - Bystron, Tomas A1 - Loukrakpam, Rameshwori A1 - Melke, Julia A1 - Lobo, Carlos M. S. A1 - Fink, Michael A1 - Zhu, Mengshu A1 - Voloshina, Elena A1 - Kutter, Maximilian A1 - Hoffmann, Hendrik A1 - Yusenko, Kirill V. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Röder, Bettina A1 - Bouzek, Karel A1 - Paulus, Beate A1 - Roth, Christina T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR). The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition. KW - H3PO4 life cycle KW - XAS KW - In situ coupling KW - High-temperature fuel cells KW - H3PO3, KW - Δμ XANES PY - 2022 DO - https://doi.org/10.1021/acscatal.2c02630 SN - 2155-5435 VL - 12 IS - 18 SP - 11472 EP - 11484 PB - American Chemical Society (ACS) AN - OPUS4-64733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yun, Tae Gyu A1 - Chen, Boqiang A1 - Wells, Sarah A1 - Lim, Younghwan A1 - Kim, Jun Seop A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Waegele, Matthias M. A1 - Risch, Marcel A1 - Grimaud, Alexis ED - de Oliveira Guilherme Buzanich, Ana T1 - Extrinsic and Intrinsic Factors Governing the Electrochemical Oxidation of Propylene in Aqueous Solutions N2 - The electrochemical synthesis of commoditychemicals such as epoxides and glycols offers a sustainablealternative to conventional methods that involve hazardouschemicals. Efforts to improve the yield and selectivity of propyleneoxidation using Pd-based catalysts have been shown to be highlysensitive to applied potential, pH, and electrochemical cell design.Record efficiencies and yields were obtained by substitution ofPdO by 4d or 5d transition metals, including Pt, with thus far littlerationale regarding the origin for the improvement. Throughelectrochemical analysis, scanning transmission electron micros-copy, X-ray absorption spectroscopy, and surface-enhanced infraredabsorption spectroscopy, we investigated the mechanism ofpropylene oxidation on Pd-based catalysts. We demonstrate thatadsorbates forming on PdO, where Pd adopts a square-planar coordination [PdO4], differ from that forming on the surface ofoxidized metallic Pd catalysts with an oxo intermediate mediating propylene oxidation on PdO. We further show that Pt substitutionin PdO does not modify this oxo intermediate. Varying pH, we found that the onset for propylene oxidation is pH independent,indicating a potential-determining step where the proton is not involved in and similar reaction pathway in acidic and near-neutralconditions. Finally, our work undoubtedly demonstrates that high Faradaic efficiency toward propylene glycol and propylene oxideformation, such as those previously reported in the literature, can be achieved by means of electrode engineering and mastery ofmass transport and local pH. Notably, we achieved ≈100% faradaic efficiency for propylene glycol at 1.7 V vs RHE in acidic mediausing a Pt-substituted PdO catalyst loaded onto a gas diffusion electrode. KW - XAS KW - Electrochemistry KW - Popylene oxidation KW - 4d metals PY - 2025 DO - https://doi.org/10.1021/jacs.5c02585 SN - 0002-7863 VL - 147 IS - 14 SP - 12318 EP - 12330 PB - American Chemical Society (ACS) AN - OPUS4-63112 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Somasundaram, S. K. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska A1 - Krishnan, S. A1 - Senthilkumar, K. A1 - Joseyphus, R.J. T1 - New insights into pertinent Fe-complexes for the synthesis of iron via the instant polyol process N2 - Chemically synthesized iron is in demand for biomedical applications due to its large saturation magnetization compared to iron oxides. The polyol process, suitable for obtaining Co and Ni particles and their alloys, is laborious in synthesizing Fe. The reaction yields iron oxides, and the reaction pathway remains unexplored. This study shows that a vicinal polyol, such as 1,2-propanediol, is suitable for obtaining Fe rather than 1,3-propanediol owing to the formation of a reducible Fe intermediate complex. X-ray absorption spectroscopy analysis reveals the ferric octahedral geometry and tetrahedral geometry in the ferrous state of the reaction intermediates in 1,2-propanediol and 1,3-propanediol, respectively. The final product obtained using a vicinal polyol is Fe with a γ-Fe2O3 shell, while the terminal polyol is favourable for Fe3O4. The distinct Fe–Fe and Fe–O bond lengths suggest the presence of a carboxylate group and a terminal alkoxide ligand in the intermediate of 1,2-propanediol. A large Fe–Fe bond distance suggests diiron complexes with bidentate carboxylate bridges. Prominent high-spin and low-spin states indicate the possibility of transition, which favors the reduction of iron ions in the reaction using 1,2-propanediol. KW - XAS KW - Nanoparticle PY - 2023 DO - https://doi.org/10.1039/D3CP01969A SN - 1463-9076 VL - 25 IS - 33 SP - 21970 EP - 21980 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bruna, F. G. A1 - Prokop, M. A1 - Bystron, T. A1 - Loukrakpam, R. A1 - Melke, J. A1 - Lobo, C. M. S. A1 - Fink, M. A1 - Zhu, M. A1 - Voloshina, E. A1 - Kutter, M. A1 - Hoffmann, H. A1 - Yusenko, Kirill A1 - de Oliveira Guilherme Buzanich, Ana A1 - Röder, B. A1 - Bouzek, K. A1 - Paulus, B. A1 - Roth, C. T1 - Following adsorbed intermediates on a platinum gas diffusion electrode in H3PO3‑containing electrolytes using in situ X‑ray absorption spectroscopy N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalyst with H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR). The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition. KW - H3PO4 life cycle KW - XAS KW - In situ coupling KW - High-temperature fuel cells KW - Δμ XANES KW - H3PO3 PY - 2022 DO - https://doi.org/10.1021/acscatal.2c02630 SN - 2155-5435 VL - 12 IS - 18 SP - 11472 EP - 11484 PB - ACS CY - Washington, DC AN - OPUS4-55815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falqueto, J. B. A1 - Clark, A. H. A1 - Štefančič, A. A1 - Smales, Glen Jacob A1 - Vaz, C. A. F. A1 - Schuler, A. J. A1 - Bocchi, N. A1 - Kazzi, M. E. T1 - High performance doped Li-rich Li1+xMn2–xO4 cathodes nanoparticles synthesized by facile, fast, and efficient microwave-assisted hydrothermal route N2 - Li-rich nanoparticles of Li1+xMn2–xO4 doped with Al, Co, or Ni are successfully synthesized using a facile, fast, and efficient microwave-assisted hydrothermal route. Synchrotron X-ray diffraction confirms the formation of the crystalline cubic spinel phase type. X-ray absorption spectroscopy analysis at the Co and Ni K- and L-edges verifies that the dopants are within the Li1+xMn2–xO4 spinel structure and are inactive during cycling in the bulk and at the surface. Moreover, we demonstrate that nanocrystallinity and cationic doping play an important role in improving the electrochemical performance with respect to LiMn2O4 microparticles. They significantly reduce the charge-transfer resistance, lower the first cycle irreversible capacity loss to 6%, and achieve a capacity retention between 85 and 90% after 380 cycles, with excellent Coulombic efficiency close to 99% without compromising the specific charge at a 5C cycling rate. Furthermore, the Mn K- and L-edges attest that after long cycling, the Mn oxidation state in the bulk differs from that at the surface caused by the Mn disproportion reaction; however, the cationic doping helps mitigate the Mn dissolution with respect to the undoped Li1+xMn2–xO4 nanoparticles, as indicated by inductively coupled plasma atomic emission spectrometry. KW - XAS KW - SAXS KW - Li-ion battery KW - Cathode material KW - Spinel KW - The MOUSE PY - 2022 DO - https://doi.org/10.1021/acsaem.2c00902 SN - 2574-0962 VL - 5 IS - 7 SP - 8357 EP - 8370 PB - ACS Publ. CY - Washington, DC AN - OPUS4-55359 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lin, R. A1 - Li, X. A1 - Krajnc, A. A1 - Li, Z. A1 - Li, M. A1 - Wang, W. A1 - Zhuang, L. A1 - Smart, S. A1 - Zhu, Z. A1 - Appadoo, D. A1 - Harmer, J. R. A1 - Wang, Z. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Beyer, S. A1 - Wang, L. A1 - Mali, G. A1 - Bennett, T. D. A1 - Chen, V. A1 - Hou, J. T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly KW - Electrodes KW - MOF KW - OER KW - XANES KW - XAS KW - Bimetallic frameworks PY - 2022 DO - https://doi.org/10.1002/anie.202112880 VL - 61 IS - 4 SP - e202112880 PB - Wiley AN - OPUS4-54018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -