Search

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As ammonia continues to gain more and more interest as a promising hydrogen carrier compound, so does the electrochemical ammonia oxidation reaction (AmOR). To avoid the liberation of H2 in a reverse Haber–Bosch reaction under release of the energetically more favorable N2, we propose the oxidation of ammonia to value‐added nitrite (NO2−), which is usually obtained during the Ostwald process. We investigated the anodic oxidation of gaseous ammonia directly supplied to a gas diffusion electrode (GDE) using a variety of compositionally different multi‐metal catalysts coated on Ni foam under the simultaneous formation of H2 at the cathode. This will double the amount of H2 per ammonia molecule while applying a lower overpotential than that required for water electrolysis (1.4–1.8 V vs. RHE at 50 mA ⋅ cm−2). A selectivity study demonstrated that some of the catalyst compositions were able to produce significant amounts of NO2−, and further investigations using the most promising catalyst composition Nif_AlCoCrCuFe integrated within a GDE demonstrated up to 88 % Faradaic efficiency for NO2− at the anode coupled to close to 100 % Faradaic efficiency for the cathodic H2 production. [ABSTRACT FROM AUTHOR]

The investigation delves into the functionality exhibited by ferroelectric BiFe0.95Mn0.05O3 (BFM) nanoparticles (NPs) concerning the hydrogen evolution reaction (HER). The electrocatalytic activity of BFM NPs undergoes a transformative shift as a consequence of mono‐, di‐, and tri‐valent cation substitution. Notably, the strategic engineering of doping at the Bi site within BFM NPs yields a remarkable outcome, namely the conspicuous reduction of the kinetic overpotential prerequisite for HER. This diminished overpotential in doped BFM NPs arises from the confluence of multifarious factors: diminished charge transfer resistance, augmented specific surface area, a discernible distribution of pore sizes ranging from narrow to broad, particles endowed with a shape boasting abundant active facets, and the integration of dopants as novel active sites on the surface. Furthermore, the presence of surface defects, oxygen vacancies, and amplified microstrain within doped BFM NPs contributes to the reduction in overpotential. [ABSTRACT FROM AUTHOR]

Carbon dioxide electroreduction (CO2R) is a promising technology for mitigating industrial CO2 emissions and generating valuable chemicals using renewable energy sources. Recent advances have centered on fine‐tuning catalyst materials and their micro‐environments, stimulating interest within the CO2R community. However, testing novel catalyst materials often occurs under conditions different from those relevant to industrial applications. In this study, we explore the transferability of CO2R results obtained using Ag‐based gas diffusion electrode (GDEs) in an easy to fabricate, assemble and test zero‐gap half‐cell (ZGHC) to a zero‐gap electrolyzer (ZGE). Our investigation reveals that the transferability of results is not only influenced by the reactor design, but also partially dependent on the type of additive used in the catalyst layer of the GDE. Moreover, we show that the humidity of the CO2 is a crucial operational parameter that not only impacts the selectivity of the electrode but also influences its stability during testing in the ZGHC. These findings highlight the importance of comprehensively considering operational conditions as well as reactor designs when comparing results between the ZGHC and ZGE, presenting finally a pathway on how to minimize such differences. [ABSTRACT FROM AUTHOR]

The electrochemical conversion of carbon dioxide by means of renewable electricity holds great promise. However, despite significant progress in current literature, there remains a significant gap between fundamental research and the industrial demands to establish new disruptive technologies in real world applications. This gap primarily arises from a mismatch between performance parameters and requirements in both areas, leading to significant challenges in technology transfer. We herein suggest pathways to bridge this gap and outline current limitations in the field, proposing key parameters and procedures towards accelerated and streamlined technology development. Despite significant progress in CO2 conversion field, there remains a significant gap between fundamental research and the industrial demands. This Comment discusses key performance parameters for industrial applications and outlines current limitations in the field. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of CO2 (CO2RR) has received significant attention since it could provide pathways for renewable energy storage to energy‐dense chemicals and synthetic fuels. We developed a novel CuOx/Cu/C type electrocatalyst via pyrolysis, which we used to convert CO2 at industrially relevantly current densities using gas diffusion electrodes. The influence of the pyrolysis conditions on the electrocatalytic CO2RR activity and selectivity was evaluated. Optimization of the electrode structure to mitigate electrowetting was done by mixing the catalyst with polytetrafluoroethylene (PTFE). We found that mixing the most active catalyst with PTFE in a mass ratio of 1 to 0.25 substantially increased the formation of C2H4 displaying 41% Faradaic efficiency (FE) at –240 mA cm–2. Prolonged CO2RR at different current densities shows that the electrode containing 25 wt.% PTFE in the catalyst layer display FEC2H4 > 40% at –280 mA cm–2 for 2 h. [ABSTRACT FROM AUTHOR]