Hybrid CIGS-Cobalt Quaterpyridine Photocathode with Backside Illumination: a New Paradigm for Solar Fuel Production.

Chalcogenide-based thin-film solar cell optimized for rear illumination and used for CO2 reduction is presented. Central to this innovation is a thinner, Cu(In,Ga)S2 chalcopyrite absorber coated with a robust metallic top layer, which potentially surpasses the performance of conventional front-illuminated designs. Using cobalt quaterpyridine molecular catalyst, photocurrent densities for CO2 reduction exceeding 10 mA/cm2 at 0.

Four-electron reduction of CO: from formaldehyde and acetal synthesis to complex transformations.

The expansive and dynamic field of the CO Reduction Reaction (CORR) seeks to harness CO as a sustainable carbon source or energy carrier. While significant progress has been made in two, six, and eight-electron reductions of CO, the four-electron reduction remains understudied. This review fills this gap, comprehensively exploring CO reduction into formaldehyde (HCHO) or acetal-type compounds (EOCHOE, with E = [Si], [B], [Zr], [U], [Y], [Nb], [Ta] or -R) using various CORR systems.

Operando Spectroelectrochemistry Unravels the Mechanism of CO Electrocatalytic Reduction by an Fe Porphyrin.

Iron porphyrins are molecular catalysts recognized for their ability to electrochemically and photochemically reduce carbon dioxide (CO). The main reduction product is carbon monoxide (CO). CO holds significant industrial importance as it serves as a precursor for various valuable chemical products containing either a single carbon atom (C1), like methanol or methane, or multiple carbon atoms (Cn), such as ethanol or ethylene.

Molecular Electrochemical Catalysis of CO-to-Formaldehyde Conversion with a Cobalt Complex.

Formox, a highly energy-intensive process, currently serves as the primary source of formaldehyde (HCHO), for which there is a crucial and steadily growing chemical demand. The alternative electrochemical production of HCHO from C1 carbon sources such as CO and CO is still in its early stages, with even the few identified cases lacking mechanistic rationalization. In this study, we demonstrate that cobalt phthalocyanine (CoPc) immobilized on multiwalled carbon nanotubes (MW-CNTs) constitutes an excellent electrocatalytic system for producing HCHO with productivity through the direct reduction of CO, the two-electron reduction product of CO.

Carbon nanotube heterogenization improves cobalt pyridyldiimine complex CO reduction activity in aqueous carbonate buffer.

We present two novel cobalt pyridyldiimine complexes functionalized with pyrene. Initially modest in homogeneous acetonitrile solution, their electrocatalytic CO reduction performance significantly improves upon immobilization on MWCNTs in an aqueous carbonate buffer. The complexes exhibit outstanding stability, with CO selectivity exceeding 97%, and TON and TOF values reaching up to 10 and above 1.

Backbone Engineering of Polymeric Catalysts for High-Performance CO Reduction in Bipolar Membrane Zero-Gap Electrolyzer.

Bipolar membranes (BPMs) have emerged as a promising solution for mitigating CO losses, salt precipitation and high maintenance costs associated with the commonly used anion-exchange membrane electrode assembly for CO reduction reaction (CORR). However, the industrial implementation of BPM-based zero-gap electrolyzer is hampered by the poor CORR performance, largely attributed to the local acidic environment. Here, we report a backbone engineering strategy to improve the CORR performance of molecular catalysts in BPM-based zero-gap electrolyzers by covalently grafting cobalt tetraaminophthalocyanine onto a positively charged polyfluorene backbone (PF-CoTAPc).

Efficient Visible-Light-Driven Carbon Dioxide Reduction using a Bioinspired Nickel Molecular Catalyst.

Inspired by natural enzymes, this study presents a nickel-based molecular catalyst, [Ni(NS)]Cl (NiNS, NS=2,11-dithia[3,3](2,6)pyridinophane), for the photochemical catalytic reduction of CO under visible light. The catalyst was synthesized and characterized using various techniques, including liquid chromatography-high resolution mass spectrometry (LC-HRMS), UV-Visible spectroscopy, and X-ray crystallography. The crystallographic analysis revealed a slightly distorted octahedral coordination geometry with a mononuclear Ni cation, two nitrogen atoms and two sulfur atoms.

Antenna Effect in Noble Metal-Free Dye-Sensitized Photocatalytic Systems Enhances CO -to-CO Conversion.

Dye-sensitized photocatalytic systems (DSPs) have been extensively investigated for solar-driven hydrogen (H ) evolution. However, their application in carbon dioxide (CO ) reduction remains limited. Furthermore, current solar-driven CO -to-CO DSPs typically employ rhenium complexes as catalysts.

A CuCo cryptate for the visible light-driven reduction of CO.

Among the rare bimetallic complexes known for the reduction of CO, CoCo and ZnCo hexamine cryptates are described as efficient photocatalysts. In close relation to the active sites of natural, CO-reducing enzymes, we recently reported the asymmetric cryptand {NN} ({NN} = N[(CH)SCH(-CH)CHNH(CH)]N) comprising distinct sulphur- and nitrogen-rich binding sites and the corresponding CuM (M = Co, Ni, Cu) complexes. To gain insight into the effect of metals in different oxidation states and sulphur-incorporation on the photocatalytic activity, we herein investigate the CuCo complex of {NN} as catalyst for the visible light-driven reduction of CO.

Visible-Light-Driven CO Reduction with Homobimetallic Complexes. Cooperativity between Metals and Activation of Different Pathways.

Visible-light-driven reduction of CO to both CO and formate (HCOO) was achieved in acetonitrile solutions using a homobimetallic Cu bisquaterpyridine complex. In the presence of a weak acid (water) as coreactant, the reaction rate was enhanced, and a total of ca. 766 TON (turnover number) was reached for the CO reduction, with 60% selectivity for formate and 28% selectivity for CO, using Ru(phen) as a sensitizer and amines as sacrificial electron donors.

1D/2D interface engineering of a CoPc-CN heterostructure for boosting the nitrogen reduction reaction to NH.

Herein, we demonstrate the construction of a 1D/2D heterostructure of cobalt phthalocyanine (CoPc)-carbon nitride (CN) for electrochemical N reduction to NH. Improved performance originates from the higher exposure of active surface sites. The electrochemical NRR performance showed an NH formation rate of 423.

In-situ spectroscopic probe of the intrinsic structure feature of single-atom center in electrochemical CO/CO reduction to methanol.

While exploring the process of CO/CO electroreduction (CORR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of CORR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO to methanol is strongly decreased in CORR.

Controlling the Hydrophilicity of the Electrochemical Interface to Modulate the Oxygen-Atom Transfer in Electrocatalytic Epoxidation Reactions.

The electrocatalytic epoxidation of alkenes at heterogeneous catalysts using water as the sole oxygen source is a promising safe route toward the sustainable synthesis of epoxides, which are essential building blocks in organic chemistry. However, the physicochemical parameters governing the oxygen-atom transfer to the alkene and the impact of the electrolyte structure on the epoxidation reaction are yet to be understood. Here, we study the electrocatalytic epoxidation of cyclooctene at the surface of gold in hybrid organic/aqueous mixtures using acetonitrile (ACN) solvent.

Electrification of a Milstein-type catalyst for alcohol reformation.

Novel energy and atom efficiency processes will be keys to develop the sustainable chemical industry of the future. Electrification could play an important role, by allowing to fine-tune energy input and using the ideal redox agent: the electron. Here we demonstrate that a commercially available Milstein ruthenium catalyst (1) can be used to promote the electrochemical oxidation of ethanol to ethyl acetate and acetate, thus demonstrating the four electron oxidation under preparative conditions.

Electrocatalytic CO Reduction with a Binuclear Bis-Terpyridine Pyrazole-Bridged Cobalt Complex.

A pyrazole-based ligand substituted with terpyridine groups at the 3 and 5 positions has been synthesized to form the dinuclear cobalt complex 1, that electrocatalytically reduces carbon dioxide (CO ) to carbon monoxide (CO) in the presence of Brønsted acids in DMF. Chemical, electrochemical and UV-vis spectro-electrochemical studies under inert atmosphere indicate pairwise reduction processes of complex 1. Infrared spectro-electrochemical studies under CO and CO atmosphere are consistent with a reduced CO-containing dicobalt complex which results from the electroreduction of CO .

Molecular Electrochemical Reductive Splitting of Dinitrogen with a Molybdenum Complex.

Nitrogen reduction under mild conditions (room T and atmospheric P), using a non-fossil source of hydrogen remains a challenge. Molecular metal complexes, notably Mo based, have recently been shown to be active for such nitrogen fixation. We report electrochemical N splitting with a Mo triphosphino complex [(PPP)MoI ], at room temperature and a moderately negative potential.

Obstacles affecting the management innovation process through different actors during the covid-19 crisis: a longitudinal study of Industry 4.0.

Industry 4.0 represents the most advanced stage of organization of industrial companies, allowing them to respond to an uncertain and changing environment, particularly as accentuated by the recent crisis resulting from COVID-19. Management innovation (MI) contributes to this process of permanent adaptation.

On the Existence and Role of Formaldehyde During Aqueous Electrochemical Reduction of Carbon Monoxide to Methanol by Cobalt Phthalocyanine.

A long-time challenge in aqueous CO electrochemical reduction is to catalyze the formation of products beyond carbon monoxide with selectivity. Formaldehyde is the simplest of these products and one of the most relevant due to its broad use in the industry. Paradoxically it is one of the less reported product.

Highly Efficient Photocatalytic Reduction of CO to CO by In Situ Formation of a Hybrid Catalytic System Based on Molecular Iron Quaterpyridine Covalently Linked to Carbon Nitride.

Efficient and selective photocatalytic CO reduction was obtained within a hybrid system that is formed in situ via a Schiff base condensation between a molecular iron quaterpyridine complex bearing an aldehyde function and carbon nitride. Irradiation (blue LED) of an CH CN solution containing 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH), triethylamine (TEA), Feqpy-BA (qpy-BA=4-([2,2':6',2'':6'',2'''-quaterpyridin]-4-yl)benzaldehyde) and C N resulted in CO evolution with a turnover number of 2554 and 95 % selectivity. This hybrid catalytic system unlocks covalent linkage of molecular catalysts with semiconductor photosensitizers via Schiff base reaction for high-efficiency photocatalytic reduction of CO , opening a pathway for diverse photocatalysis.

Taming Electron Transfers: From Breaking Bonds to Creating Molecules.

The electron is the ultimate redox reagent to build and reshape molecular structures. Understanding and controlling the parameters underlying dissociative electron transfer (DET) reactivity and its coupling with proton transfer is crucial for combining selectivity, kinetics and energy efficiency in molecular chemistry. Reactivity understanding and mechanistic elements in DET processes are traced back and key examples of current research efforts are presented, demonstrating a large variety of applications.

Electrocatalytic and Photocatalytic Reduction of Carbon Dioxide by Earth-Abundant Bimetallic Molecular Catalysts.

Converting CO into useful resources by electrocatalysis and photocatalysis is a promising strategy for recycling of the gas and electrification of industries. Numerous studies have shown that multinuclear metal catalysts have higher selectivity and catalytic activity than monometallic catalysts due to the synergistic effects between the metal sites. In this review, we summarize some of the recent progress on the electrocatalytic and photocatalytic reduction of CO by earth-abundant bimetallic molecular catalysts.

Hybridization of Molecular and Graphene Materials for CO Photocatalytic Reduction with Selectivity Control.

In the quest for designing efficient and stable photocatalytic materials for CO reduction, hybridizing a selective noble-metal-free molecular catalyst and carbon-based light-absorbing materials has recently emerged as a fruitful approach. In this work, we report about Co quaterpyridine complexes covalently linked to graphene surfaces functionalized by carboxylic acid groups. The nanostructured materials were characterized by X-ray photoemission spectroscopy, X-ray absorption spectroscopy, IR and Raman spectroscopies, high-resolution transmission electron microscopy and proved to be highly active in the visible-light-driven CO catalytic conversion in acetonitrile solutions.