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Capturing and electrochemically converting carbon dioxide (CO2) from industrial point sources, such as flue gas, is a promising approach to mitigate the greenhouse effect and protect the environment. However, these processes are characterized by high energy consumption and low energy efficiency, which need optimization. This prospective article provides a summary of the current strategies for capturing and electrochemically converting dilute CO2 into valuable products. We will summarize strategies for capture and electrochemical reduction of CO2 in a dilute stream, compare the advantages and disadvantages of using amines, membranes, alkaline solutions, and molten salts for CO2 capture and conversion, and discuss the effects of CO2 concentrations and typical impurities in flue gas (NOx, SOx, and O2) on the performance of electrochemical CO2 conversion. We will also provide an outlook on future opportunities for developing integrated processes for capturing and electrochemically converting CO2 to valuable products. [ABSTRACT FROM AUTHOR]

Designing high‐performance and cost‐effective electrocatalysts for water splitting at high current density is pivotal for practical industrial applications. Herein, it is found that atomic‐level surface engineering of self‐supported nickel phosphide (NiP) nanoarrays via a facile cation‐exchange method can substantially regulate the chemical and physical properties of catalysts by introducing Co atoms. Such surface‐engineered NixCo1–xP endows several aspects of merits: i) rough nanosheet array electrode structure accessible to diffusion of electrolytes and release of gas bubbles, ii) enriched P vacancies companied by Co doping and thus increased active sites, and iii) the synergy of Ni5P4 and NiP2 beneficial to catalytic activity enhancement. By virtue of finely controlling the Co contents, the optimal Ni0.96Co0.04P electrode achieves remarkable bifunctional electrocatalytic performance for overall water splitting at a large current density of 1000 mA cm−2, showing overpotentials of 249.7 mV for hydrogen evolution reaction and 281.7 mV for oxygen evolution reaction. Furthermore, the Ni0.96Co0.04P electrode at 500 mA cm−2 exhibits an ultralow potential (1.71 V) and ultralong durability (500 h) for overall water splitting. This study implies that the atomic‐level surface engineering of the electrode materials offers a viable route for gaining high‐performance catalysts for water splitting at large current density. [ABSTRACT FROM AUTHOR]

Acid environment was found to play a critical role in regulating the catalytic behavior of IrO2 duringthe oxygen evolution reaction ( OER). As demonstrated by Jingguang G. Chen, Ping Liu et al. in their Research Article ( e202409526), the presence of hydronium cation ( H3O+) introduces an internal electric field at the interface. It allows selective bond- tuning of the reaction intermediates and formation of partial surface hydroxylation under the operational conditions, which actively catalyzed the OER. [Extracted from the article]

Direct ethanol fuel cells are one of the most promising electrochemical energy conversion devices for portable electronics and electric vehicles. Highly efficient and robust electrocatalysts for the ethanol oxidation reaction are therefore desired. In this paper, we report a facile approach for synthesizing monodisperse PdSn/SnOx core/shell nanoparticles as high-performance catalysts for electrochemical ethanol oxidation reaction (EOR). The mass current density of PdSn/SnOx reached 3.2 A mgPd−1 at 0.85 V vs. RHE in 1 M KOH solution, which is 3.2 times higher than that of the commercial Pd catalyst. More importantly, these PdSn/SnOx core/shell nanoparticles exhibit enhanced stability compared with the commercial Pd catalyst. Density functional theory calculations suggest that the strong d–p orbital coupling and sp-electron transfer in the PdSn alloy weaken the adsorption of carbonaceous species, e.g., the acetate-evolution intermediate *CH3CO and the poisoning species *CO, at Pd sites. Consequently, the destabilization of these species facilitates their coupling with *OH, leading to enhanced EOR activity and poison resistance. Meanwhile, we found that amorphous SnOx layers possess rich Sn–Sn ensembles with stronger adsorption of *OH, providing a shuttling path of hydroxide ions to surface sites. [ABSTRACT FROM AUTHOR]

The development of active, stable, and more affordable electrocatalysts for acidic oxygen evolution reaction (OER) is of great importance for the practical application of electrolyzers and the advancement of renewable energy conversion technologies. Currently, IrO2 is the only catalyst with high stability and activity, but a high cost. Further optimization of the catalyst is limited by the lack of understanding of catalytic behaviors at the acid-IrO2 interface. Here, in strong interaction with the experiment, we develop an explicit model based on grand-canonical density function theory (GC-DFT) calculations to describe acidic OER over IrO2. Compared to the explicit models reported previously, hydronium cations (H3O+) are introduced at the electrochemical interface in the current model. As a result, a variation in stable IrO2 surface configuration under the OER operating condition from previously proposed complete *O-coverage to a mixture coverage of *OH and *O is revealed, which is well supported by in situ Raman measurements. In addition, the accuracy of predicted overpotential is increased in comparison with the experimentally measured. More importantly, an alteration of the potential limiting step from previously identified *O → *OOH to *OH → *O is observed, which opens new opportunities to advance the IrO2-based catalysts for acidic OER., (© 2024 Wiley‐VCH GmbH.)

Reducing iridium (Ir) catalyst loading for acidic oxygen evolution reaction (OER) is a critical strategy for large-scale hydrogen production via proton exchange membrane (PEM) water electrolysis. However, simultaneously achieving high activity, long-term stability, and reduced material cost remains challenging. To address this challenge, we develop a framework by combining density functional theory (DFT) prediction using model surfaces and proof-of-concept experimental verification using thin films and nanoparticles. DFT results predict that oxidized Ir monolayers over titanium nitride (IrO x /TiN) should display higher OER activity than IrO x while reducing Ir loading. This prediction is verified by depositing Ir monolayers over TiN thin films via physical vapor deposition. The promising thin film results are then extended to commercially viable powder IrO x /TiN catalysts, which demonstrate a lower overpotential and higher mass activity than commercial IrO 2 and long-term stability of 250 h to maintain a current density of 10 mA cm -2 . The superior OER performance of IrO x /TiN is further confirmed using a proton exchange membrane water electrolyzer (PEMWE), which shows a lower cell voltage than commercial IrO 2 to achieve a current density of 1 A cm -2 . Both DFT and in situ X-ray absorption spectroscopy reveal that the high OER performance of IrO x /TiN strongly depends on the IrO x -TiN interaction via direct Ir-Ti bonding. This study highlights the importance of close interaction between theoretical prediction based on mechanistic understanding and experimental verification based on thin film model catalysts to facilitate the development of more practical powder IrO x /TiN catalysts with high activity and stability for acidic OER.

The electrochemical CO 2 reduction reaction (ECO 2 RR) driven by renewable electricity holds promise to store intermittent energy in chemical bonds, while producing value-added chemicals and fuels sustainably. Unfortunately, it remains a grand challenge to simultaneously achieve a high faradaic efficiency (FE), a low overpotential, and a high current density of the ECO 2 RR. Herein, we report the synthesis of heterostructured Bi-Cu 2 S nanocrystals via a one-pot solution-phase method. The epitaxial growth of Cu 2 S on Bi leads to abundant interfacial sites and the resultant heterostructured Bi-Cu 2 S nanocrystals enable highly efficient ECO 2 RR with a largely reduced overpotential (240 mV lower than that of Bi), a near-unity FE (>98%) for formate production, and a high partial current density (2.4- and 5.2-fold higher J HCOO - than Cu 2 S and Bi at -1.0 V vs. reversible hydrogen electrode, RHE). Density functional theory (DFT) calculations show that the electron transfer from Bi to Cu 2 S at the interface leads to the preferential stabilization of the formate-evolution intermediate (*OCHO).