EnviroESCA

Nutritional supplements such as trace element-enriched yeasts are becoming increasingly popular to overcome the worldwide problem of zinc (Zn) deficiency. Unlike selenium-enriched yeast, which is already authorized in the European Union, Znenriched yeasts (ZnY) have not yet been approved for food purposes in the European Union, as their evaluation is still ongoing, demanding more comprehensive data regarding the Zn species present in ZnY. This study screens ten different industrial yeast strains regarding their Zn-enrichment quota, with further characterization of selected strains using spectroscopic and proteomic approaches. Microfermentation experiments on the industrial yeasts showed Zn levels spanning 0.06–51 pg/cell. Large-scale fermentation in bioreactors was carried out with two strains excelling in either biomass or Zn accumulation. A combination of inductively coupled plasma mass spectrometry (ICP-MS) and various spectroscopic methods confirmed the Zn enrichment, while suggesting that fractions of the Zn accumulated on the cell surface, with simultaneously high values of phosphorus being present. Speciation via X-ray absorption spectroscopy (XAS) analyses revealed that Zn species are transformed and Zn is coordinated to P-O-ligands and to amino acid ligands in both strains. Proteomic analysis showed that ZnY cells moved from a Zap1-governed Zn balance to an intracellular excess response, implying cellular Zn uptake. This study demonstrates that, in a Zn-excess medium, industrial yeast strains exhibit variability in Zn-accumulation capacity, cellular Zn-localization, and regulatory responses involving the expression of Zn-binding proteins. The presented findings contribute to optimizing industrial fermentation processes for producing Zn-rich yeast biomass and enhance the understanding of Zn regulation in yeast, aiding in the approval of Zn-enriched yeasts for supplements and novel food applications.

Gina Grimmer,Julia Muenzner,Maximillian Schmacht,Maria Angels Subirana,Iris H. Valido,Philip Nickl,Paul M. Dietrich,Ievgen S. Donskyi,Dirk Schaumlöffel,Martin Hageböck,Michael Mülleder,Markus Ralser,Hajo Haase,Martin Senz,Maria Maares & Claudia Keil
Applied Microbiology and Biotechnology

Photocatalytic reduction of CO2 to methanol using water as a proton source offers a sustainable pathway for solar
energy storage and carbon neutrality. However, its practical application is hindered by low quantum efficiency,
rapid charge recombination, and reliance on sacrificial agents. Herein, we developed a bimetallic AuCu alloy
supported on TiO2 nanoparticles (AuCu-TiO2) via a NaBH4 reduction method for efficient CO2-to-methanol
conversion in the absence of sacrificial agents. The photocatalytic performance was correlated with in situ FTIR
spectroscopy to unravel the synergistic roles of AuCu alloy sites and TiO2 in mediating CO2 reduction and H2O
oxidation. CO2 activation by photogenerated electrons leads to the formation of critical intermediates like
COOH* and CHO*, which undergo sequential hydrogenation to produce methanol. The Au-Cu synergy facilitates
the hydrogenation of COOH* to CHO*, significantly boosting methanol selectivity. By optimizing the AuCu
loading and Cu/Au molar ratio, the AuCu-TiO2 catalyst achieved a high methanol production rate of 63.31 μmol
g? 1 h? 1 with 85.59 % selectivity. This work provides a general strategy for designing efficient bimetallic photocatalysts
for selective CO2 conversion under environmentally benign conditions.

Gangye Cen, Weiqun Chu, Jianfeng Lu, Jing Ding, Yukun Hu, Weilong Wang
Journal of Environmental Chemical Engineering

Topological materials are promising electrocatalysts for the hydrogen evolution reaction (HER) because of their protected electronic states and exceptional carrier mobility. Among them, the topological metal Pt3Te4 (mitrofanovite) exhibits low Tafel slopes in the nano crystals. Realizing this potential in scalable catalyst systems requires nanoscale texturing coupled with precise control of the surface chemistry under operating conditions. Herein, we demonstrate that hydrogenperoxide (H2O2)-assisted liquid-phase exfoliation (LPE) of bulkPt3Te4 yields nanoporous nanosheets that retain their metallic character and are chemically preconditioned to develop a bias-controlled PtO2 skin that governs the catalytic activity. Crucially, spectromicroscopy resolves termination-selective oxidation:PtO2 forms exclusivelyonPtTe2 liketerminations,whereasPt2Te2terminationsremainmetallic.Operando ambient-pressure X-ray photoelectron spectroscopy (AP XPS) in an electrochemical cell revealed the bias-dependent emergence of surface oxide phases inH2O2-treatednanosheets.The joint effect of the higher accessible site density imparted by nano porosity and the emergence of a bias-controlled PtO2/PtTe2 terminated Pt3Te4 surface junction rationalizes the improved catalytic activity:the over potential at 10mAcm−2 decreases by ∼30% (from 113.1 to 78.7 mV), while the exchange current density more than triples (from 0.106 to 0.347mAcm−2), all with an unchanged Tafelslope (∼53 mVdec−1) and sustainedstability over 50 h in acid.By combining a single scalable top-down step with operando proof that the catalytically active oxide is switched on by bias rather than being a staticpassivation layer, this study establishes aprecise interface-engineering principle for Pt3Te4 nanosheets and a practical path to efficient, scalable HER catalysts based on nano sheets of topological metals.

Tsotne Dadiani,Gianluca D’Olimpio,Loreta Tamasauskaite-Tamasiunaite,Stefano Zenone,
Chia-NungKuo,Matteo Amati,Zygmunt Milosz,Luca Gregoratti,Tomáš Hrbek,Miquel Gamón Rodríguez,Marian Cosmin Istrate,Chin Shan Lue,Yevheniia Lobko,Corneliu Ghi
ACS Applied Materials and Interfaces

Here, we report on ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) experiments aimed at exploring the complex surface interactions and dissolution behaviors of nanofillers in nanocomposites under high-salinity conditions pertinent to desalination and mineral recovery. In situ AP-XPS analysis at solid-liquid interfaces under near-ambient conditions provided experimental proof of salinity-induced partial dissolution and interactions with chloride ions, revealing the formation of complex surface-bound species. Transition-metal chalcogenides NiSe and CoSe were specifically selected as model nanofillers due to their potential in enhancing performance for membrane distillation (MD) and membrane crystallization (MCr) processes. Complementary density functional theory (DFT) simulations provided a detailed mechanistic understanding, offering a robust predictive framework validated by our experimental findings. This integrated approach elucidates critical physicochemical processes at the solid-liquid interface, guiding the design of more efficient and durable nanocomposite membranes for sustainable mineral recovery from brines.

Danil W. Boukhvalov, Gianluca D'Olimpio, Tsotne Dadiani, Sergio Santoro, Anna Cupolillo, Chia-Nung Kuo, Chin Shan Lue, Maya Bar-Sadan, Tomáš Hrbek, Miquel Gamón Rodríguez, Michael Vorochta, Efrem Curcio, Antonio Politano
Desalination, Volume 602, 10 May 2025, 118628

Near ambient pressure–x-ray photoelectron spectroscopy (NAP-XPS) is a less traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at greater than 5000 Pa. NAP-XPS can probe moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, we show the survey, Li 1s, S 2p, C 1s, N 1s, O 1s, and F 1s NAP-XPS spectra of a Li-based electrolyte solution, which is a material that would be difficult to analyze by conventional XPS. The measurements were performed at 200 Pa in ambient gas atmosphere to compensate for surface charging. Peak fits of the C 1s, O 1s, and F 1s narrow scans are presented.

Paul M. Dietrich, Lydia Gerlein, Julia Maibach, Andreas Thissen
J. Appl. Phys. 30, 014002 (2023)

Near ambient pressure – X-ray photoelectron spectroscopy (NAP-XPS) is a less traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at greater than 5000 Pa. NAP-XPS can probe moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, we show the survey, Li 1s, P 2p, C 1s, N 1s, O 1s, and F1s NAP-XPS spectra of a Li-based electrolyte solution, which is a material that would be difficult to analyze by conventional XPS. The measurements were performed at 1000 Pa in ambient gas atmosphere to compensate for surface charging. Peak fits of the C 1s, O 1s, and F 1s narrow scans are presented.

Paul M. Dietrich, Andreas Thissen
Surface Science Spectra 30, 014003 (2023)