A generalized machine learning framework to predict the space-time yield of methanol from thermocatalytic CO2 hydrogenation

Thermocatalytic CO2 hydrogenation to methanol is an attractive defossilization technology to combat climate change while producing a valuable platform chemical and energy carrier. However, predicting the performance of catalytic systems for this process remains a challenge. Herein, we present a machine learning framework to predict catalyst performance from experimental descriptors. A database of Cu-, Pd-, In2O3-, and ZnO-ZrO2-based catalysts with 1425 datapoints is compiled from literature and subjected to data mining. Accurate ensemble-tree models (R2 > 0.85) are developed to predict the methanol space-time yield (STY) from 12 descriptors, where the significance of space velocity, pressure, and metal content is revealed. The model prediction and its insights are experimentally validated, with a root mean squared error of 0.11 gMeOH h-1 gcat dicted methanol STY. The framework is purely data-driven, interpretable, cross-deployable to other catalytic processes, and serves as an invaluable tool for guided experiments and optimization.ISSN:1873-3883ISSN:0926-337

DNA binding, cleavage and cytotoxicity of a novel dimetallic Fe(III) triaza-cyclononane complex

A novel bimetallic Fe(III) complex with the bis(triaza-cyclononane) ligand 2,6-bis(1,4,7-triazacyclonon-1-ylmethyl)-4-methylphenol (bcmp) is reported. [Fe-2(bcmp(-H))(mu-OH)Cl-2]Cl-2 (2) contains two octahedral Fe(III) centers bound to the two triaza-cyclononane rings of bcmp. The coordination sphere is completed by one chlorine, one bridging phenolate oxygen and one bridging hydroxide group. The complex has been characterized by elemental analysis, Mossbauer spectroscopy, UV-Vis spectroscopy, pH potentiometric titration, ESI mass spectrometry and cyclic voltammetry. The complex hydrolyzes the DNA model bis (2,4-dinitrophenyl) phosphate (BDNPP) with a maximum activity a pH 7. Michaelis-Menten behavior is observed with k(cat) = 3.56 x 10(-4)s(-1) and K-m = 0.56 mM (pH 7.0, 40 degrees C). The interaction of 2 with CT DNA was studied by electronic absorption spectroscopy and gel electrophoresis. Notably, the complex relaxes supercoiled pUC19 DNA into the nicked form at low micromolar concentration (10 mu M) in the presence of an external reducing agent (ascorbic acid). Finally, the in vitro antiproliferative activity of 2 was assessed on a panel of human cancer cell lines and results revealed that the complex exhibited a significant cytotoxic effects in particular versus colon LoVo cancer cells, wih IC50 value 2.5 times lower than that shown by the reference metallodrug cisplatin (3.54 versus 8.53 mu M). (C) 2016 Elsevier B.V. All rights reserved.Financial support from the European Commission (Marie Curie FP7-IEF to D.M.); the University of Padova (Grants 60A04-0443, 60A04-3189 and 60A04-4015/15) and Science Foundation Ireland are gratefully acknowledged. T. P. A. thanks the Brazilian Government and CAPES for a Science Without Border Scholarship.peer-reviewed2018-03-0

DNA binding, cleavage and cytotoxicity of a novel dimetallic Fe(III) triaza-cyclononane complex

A novel bimetallic Fe(III) complex with the bis(triaza-cyclononane) ligand 2,6-bis(1,4,7-triazacyclonon-1-ylmethyl)-4-methylphenol (bcmp) is reported. [Fe2{bcmp(-H)}(μ-OH)Cl2]Cl2 (2) contains two octahedral Fe(III) centers bound to the two triaza-cyclononane rings of bcmp. The coordination sphere is completed by one chlorine, one bridging phenolate oxygen and one bridging hydroxide group. The complex has been characterized by elemental analysis, Mössbauer spectroscopy, UV–Vis spectroscopy, pH potentiometric titration, ESI mass spectrometry and cyclic voltammetry. The complex hydrolyzes the DNA model bis(2,4-dinitrophenyl) phosphate (BDNPP) with a maximum activity a pH 7. Michaelis–Menten behavior is observed with kcat = 3.56 × 10−4 s−1 and Km = 0.56 mM (pH 7.0, 40 °C). The interaction of 2 with CT DNA was studied by electronic absorption spectroscopy and gel electrophoresis. Notably, the complex relaxes supercoiled pUC19 DNA into the nicked form at low micromolar concentration (10 μM) in the presence of an external reducing agent (ascorbic acid). Finally, the in vitro antiproliferative activity of 2 was assessed on a panel of human cancer cell lines and results revealed that the complex exhibited a significant cytotoxic effects in particular versus colon LoVo cancer cells, wih IC50 value 2.5 times lower than that shown by the reference metallodrug cisplatin (3.54 versus 8.53 μM)

Reaktionsinduzierte Metall‐Metalloxid‐Wechselwirkungen in Pd‐In₂O₃/ZrO₂ Katalysatoren fördern die selektive und stabile CO₂‐Hydrierung zu Methanol

Ternäre Pd-In₂O₃/ZrO₂ Katalysatoren beweisen technologisches Potenzial für die CO₂-basierte Methanolsynthese, wobei die Entwicklung skalierbarer Systeme und das Verständnis komplexer dynamischer Wechselwirkungen zwischen der aktiven Phase, des Promotors und des Trägers der Schlüssel zur Erreichung einer hohen Produktivität sind. Hier zeigen wir, dass durch einfache Imprägnierung hergestellte Pd-In₂O₃/ZrO₂ Katalysatoren unter CO₂-Hydrierbedingungen eine stabile und selektive Nanoarchitektur bilden, unabhängig von der Reihenfolge der Zugabe von Pd- und In-Komponenten auf den Zirkonoxidträger. Detaillierte operando Charakterisierung und Simulationen deuten auf eine schnelle Umstrukturierung, dessen Treiber die Energie der Metall-Metalloxid-Wechselwirkung ist. Die Nähe von InOₓ-Schichten auf den entstehenden InPdₓ-Partikeln verhindern Leistungsverluste durch Pd-Sinterung. Weiterhin unterstreichen die Ergebnisse die entscheidende Rolle der reaktionsinduzierten Umstrukturierung in komplexem CO₂-Hydrierkatalysatoren und bieten Einblicke in die optimale Integration von Säure-Base- und Redoxfunktionen für die technische Umsetzung.ISSN:1521-3757ISSN:0044-824

Low-nuclearity CuZn ensembles on ZnZrOₓ catalyze methanol synthesis from CO₂

Metal promotion could unlock high performance in zinc-zirconium catalysts, ZnZrOₓ, for CO₂ hydrogenation to methanol. Still, with most efforts devoted to costly palladium, the optimal metal choice and necessary atomic-level architecture remain unclear. Herein, we investigate the promotion of ZnZrOₓ catalysts with small amounts (0.5 mol%) of diverse hydrogenation metals (Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) prepared via a standardized flame spray pyrolysis approach. Cu emerges as the most effective promoter, doubling methanol productivity. Operando X-ray absorption, infrared, and electron paramagnetic resonance spectroscopic analyses and density functional theory simulations reveal that Cu⁰ species form Zn-rich low-nuclearity CuZn clusters on the ZrO₂ surface during reaction, which correlates with the generation of oxygen vacancies in their vicinity. Mechanistic studies demonstrate that this catalytic ensemble promotes the rapid hydrogenation of intermediate formate into methanol while effectively suppressing CO production, showcasing the potential of low-nuclearity metal ensembles in CO₂-based methanol synthesis.ISSN:2041-172