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Innovative electrolyzers for carbon capture and valorization
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Increasing the Scale of Electrolyzers for Carbon Dioxide Conversion: Solving Problems and Optimizing Parameters
No full textSolar-driven integrated carbon capture and utilization: Coupling CO2 electroreduction toward CO with capture or photovoltaic systems
Full text linkElectrochemical processes have emerged as intriguing strategies for both CO2 capture and valorization, which are needed to combat global warming and climate change. Among other advantages over competing technologies, electrochemical systems can be powered by renewable sources, including solar energy.
This review aims at collecting and analyzing the main works proposed in the literature that study the coupling of electrochemical reactors for the conversion of CO2 into carbon monoxide with 1) electrochemical capture systems or 2) solar cells to power them. In addition to the critical analysis of these articles, a brief discussion of future research directions in this field is proposed
Evaluating Bicarbonate Electrolyzer Configurations for Energy‐Efficient Formate Production
Full text linkReactive carbon capture (RCC) by direct conversion of CO2 capture solutions has emerged as a promising alternative to gas-fed electrolyzers. Leveraging bicarbonate electrolyzers (BEs), RCC eliminates energy-intensive steps such as CO2 regeneration and pressurization. Additionally, BEs prevent failures like carbonate salt deposition common in gas-fed systems. However, intrinsic challenges in BEs, such as higher cell voltages and lower faradaic efficiencies (FEs), result in greater energy consumption during electrolysis compared to gas-fed electrolyzers. To evaluate whether an RCC chain (RCCC) is more energy-efficient for formate production than a gas-fed carbon chain (GFCC), the study optimizes the BE configuration and compares it to a valorization chain requiring a pure, pressurized CO2 stream for gas-fed electrolyzers. This study shows the most efficient BE setup employs a cation exchange membrane paired with a buffer layer, achieving a FE for formate of ≈75% at a current density of 100 mA cm−2 and a cell potential of 3.1 V. Using this optimized BE, the RCCC demonstrates an energetic advantage over GFCCs in scenarios without CO2 recycling. Even with 100% CO2 utilization enabled by recycling systems, RCCC remains competitive. With potential improvements in BE performance, RCCC emerges as a promising strategy for converting CO2 into formate efficiently
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A deeper understanding of flooding dynamics in gas diffusion electrodes for CO2 electrolyzer: how interfacial pressure shapes gas–liquid stability
Full text linkGas-fed CO2 electrolyzers are a promising technology for sustainable fuel and chemical production, but their industrial deployment is limited by the instability of gas diffusion electrodes (GDEs), particularly in microfluidic flow cells (MFCs). A key failure mechanism is electrode flooding, which discontinues CO2 transport and favours hydrogen evolution. Although pressure control across the gas–liquid interface has emerged as a strategy to mitigate flooding, the precise role of differential pressure (ΔP) between gas and liquid side of the GDE remains poorly understood and inconsistently defined in literature. In this work, we systematically explore how gas and liquid pressure management alters the GDE interface, focusing on the understudied “flow-by” regime. Using Cu nanoparticles as a model catalyst and operating at industrially relevant current densities (0.5 A cm−2), we monitor flooding dynamics through real-time pressure readings, product selectivity analysis, electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FE-SEM) in different electrochemical setups with several commercial Gas Diffusion Layers (GDL). Our results demonstrate that a ΔP of 30 mbar can fully suppress flooding, preserving catalyst performance and enabling selective CO2 reduction for over 6 h at 0.5 A cm−2, almost an order-of-magnitude improvement over uncontrolled system. The experimental ΔP value is confirmed by multiphysics simulations, by modelling capillary-driven liquid invasion and gas transport, in which a predicted onset value of 20 mbar is defined as the required value to prevent the flooding. This work provides the first integrated framework combining pressure tuning, diagnostics, and multi-physics simulation to define and optimize flow-by operation, offering actionable insights for designing robust, high-performance CO2 electrolyzers
Optimizing the Performance of Low-Loaded Electrodes for CO2-to-CO Conversion Directly from Capture Medium: A Comprehensive Parameter Analysis
Full text linkGas-fed reactors for CO2 reduction processes are a solid technology to mitigate CO2 accumulation in the atmosphere. However, since it is necessary to feed them with a pure CO2 stream, a highly energy-demanding process is required to separate CO2 from the flue gasses. Recently introduced bicarbonate zero-gap flow reactors are a valid solution to integrate carbon capture and valorization, with them being able to convert the CO2 capture medium (i.e., the bicarbonate solution) into added-value chemicals, such as CO, thus avoiding this expensive separation process. We report here a study on the influence of the electrode structure on the performance of a bicarbonate reactor in terms of Faradaic efficiency, activity, and CO2 utilization. In particular, the effect of catalyst mass loading and electrode permeability on bicarbonate electrolysis was investigated by exploiting three commercial carbon supports, and the results obtained were deepened via electrochemical impedance spectroscopy, which is introduced for the first time in the field of bicarbonate electrolyzers. As an outcome of the study, a novel low-loaded silver-based electrode fabricated via the sputtering deposition technique is proposed. The silver mass loading was optimized by increasing it from 116 μg/cm2 to 565 μg/cm2, thereby obtaining an important enhancement in selectivity (from 55% to 77%) and activity, while a further rise to 1.13 mg/cm2 did not provide significant improvements. The tremendous effect of the electrode permeability on activity and proficiency in releasing CO2 from the bicarbonate solution was shown. Hence, an increase in electrode permeability doubled the activity and boosted the production of in situ CO2 by 40%. The optimized Ag-electrode provided Faradaic efficiencies for CO close to 80% at a cell voltage of 3 V and under ambient conditions, with silver loading of 565 μg/cm2, the lowest value ever reported in the literature so far
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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