EES catalysis最新文献

The practical deployment of an anion exchange membrane water electrolyzer (AEMWE) relies on the exploration of active and durable electrocatalysts towards the sluggish oxygen evolution reaction (OER). Although amorphous NiFe-based catalysts (a-NiFeO_xH_y) emerge as the competitive candidate due to impressive intrinsic OER activity, their unique defective structure renders the metal sites more susceptible to over-oxidation and dissolution, leading to poor stability. To address this challenge, we incorporate borate groups (BO₃³⁻) into the a-NiFeO_xH_y lattice by occupying the oxygen vacancy sites. The bridged borates not only maintain the structural stability via filling the oxygen vacancies, but also assist electron transfer from Ni to Fe to suppress Fe ion dissolution, thereby enhancing the catalytic stability of a-NiFeO_xH_y. Moreover, the tailored electronic structure of Ni favors electrochemical reconstruction to high-valence Ni active species and optimizes adsorption of oxygen intermediates towards superior OER activity. Therefore, a-B-NiFeO_xH_y integrated into the AEMWE can deliver a noteworthy current density of 4.75 A cm⁻² at a voltage of 2.0 V and maintain stable operation at 0.5 A cm⁻² for 3000 hours. This study not only affords a promising electrocatalyst for the AEMWE, but also paves a new avenue to break the activity-stability trade-off of amorphous materials for the OER.

Electrochemical nitrate reduction (ENR) is an appealing method for remediating nitrate contamination in wastewater and producing ammonia using renewable electricity. However, a mechanistic understanding of coupled mass transfer and electrocatalysis at the electrode–electrolyte interface, which dictates ENR efficiency, is limited. In this study, we develop an experimentally-validated multiphysics model of the Stern, diffuse, and diffusion layers near the surface of a polycrystalline titanium catalyst to investigate the effect of the electric double layer on ENR. The developed model couples the generalized-modified-Nernst–Planck equation with Frumkin–Butler–Volmer kinetics and numerical optimization to quantify the effect of applied potential and bulk electrolyte concentration on the ammonia formation rate. Our results reveal how dynamic driving forces at the polarized interface give rise to experimentally observed trends in ENR. Guided by this insight, we show that a more negative potential-of-zero-charge increases the limiting current density for ammonia synthesis by enabling faster migration of nitrate towards the cathode surface. The results motivate the development of multi-scale models that link transport phenomena with molecular-scale modelling to design and tailor interfaces for efficient ENR.

Water electrolysis hydrogen production technology directly generates high-purity hydrogen through electrochemical water splitting, serving as a key technology for achieving zero-carbon emission hydrogen production. Alkaline water electrolysis demonstrates marked advantages in efficiency and rapidly developing anode catalysts in an alkaline medium. Nevertheless, the sluggish kinetics of the hydrogen evolution reaction (HER) at the cathode in an alkaline environment constitute a fundamental bottleneck that restricts the extensive application of this technology. Platinum, serving as the benchmark catalyst for the HER, is limited in its large-scale development due to its scarcity and high cost. In comparison, carbon-supported platinum-based catalysts exhibit exceptional HER catalytic activity and stability, driven by their unique electronic architecture and the synergistic effect with the support. In this review, we comprehensively examine the latest progress of carbon-supported platinum-based materials for the alkaline HER, summarize the factors contributing to the slow kinetics of the HER in an alkaline environment, and then focus on the strategies for modifying the carbon substrate and synthesizing carbon-supported platinum-based nanomaterials. Finally, the review critically evaluates existing challenges and proposes targeted research directions to advance Pt-based electrocatalysts for practical alkaline hydrogen evolution systems.

The electrosynthesis of adipic acid through the cyclohexanol oxidation reaction (COR) can address the pollution issues associated with the traditional process. However, the complexity of the electrooxidation process and unclear dehydrogenation and oxidation mechanisms limit its application. Herein, we report oxygen vacancy (V_O) modification on NiCo hydroxides for the selective electrosynthesis of adipic acid. In situ IR and DFT calculations revealed significantly enhanced adsorption capacity and an optimized process for the co-adsorption of OH⁻ and organic compounds. The V_O promotes the conversion of ketone intermediates into glycol with the addition of H₂O while inhibiting the formation of ketone alcohols. In situ synchrotron radiation and Raman analyses reveal the reversible remodeling processes of Ni²⁺–OH and Ni³⁺–OOH during the COR. Consequently, V_O-NiCo demonstrated excellent COR performance (1.32 V vs. RHE onset potential) with conversion, adipic acid selectivity, and faradaic efficiency values of 98.4%, 95.6%, and 95.2%, respectively. The system generates 8.2 times more hydrogen compared with pure water splitting at the cathode. This integrated electrocatalytic system shows potential for large-scale production of H₂ and adipic acid, offering new insights for designing advanced electrocatalysts for cost-effective and sustainable energy conversion.

The reverse water–gas shift (RWGS) reaction has been recognized as a promising strategy for CO₂ valorization. However, it faces limitations due to low activity and poor CO selectivity at low temperatures. In this study, we report that plasma can effectively promote the low-temperature RWGS reaction over Ni–In intermetallic catalysts. The formation of the Ni–In intermetallic phases completely suppresses CH₄ formation and achieves 100% CO selectivity. Through in situ transmission infrared spectroscopy (TIR) and in situ X-ray absorption fine-structure (XAFS) analysis, we monitored the changes occurring on the catalyst surface during the plasma reaction. The interaction between redox-active sites present in the Ni–In intermetallic catalysts and plasma-activated species lowers the activation energy, thereby facilitating the RWGS reaction at low temperatures. This study offers fundamental insights into how plasma-activated species enhance catalysis and the underlying mechanisms of low-temperature activation in plasma catalysis.

Plasma catalysis offers a promising alternative to current ammonia production processes, due to the combination of high selectivity of heterogenous catalysis and efficient activation of nitrogen in the plasma. However, the theoretical understanding of how various plasma processes contribute to efficiency improvements remains limited. The pioneering work of Metha et al. (Nat. Catal., 2018, 1, 269) extended the standard formulation of transition state theory by making it vibrational state-specific through the use of the Fridman–Macheret α model. The resulting microkinetic model accounted for vibrational contributions under the non-equilibrium conditions of a plasma reactor. In this work, we critically examine the prototypical chemical process of activated N₂ reactivity on ruthenium through explicit rate coefficient calculations using state-of-the-art molecular dynamics, based on a potential energy surface previously validated against molecular beam experiments. Our findings reveal that vibrational activation is significantly more effective in promoting surface reactivity than predicted by the Fridman–Macheret α model, which fails to capture the full complexity of state-specific contributions. Furthermore, our calculations indicate that vibrational activation is also the primary driver of highly activated thermal catalytic reactions. These results provide a valuable benchmark to guide the development of future state-specific microkinetic models for heterogeneous and plasma catalysis.

The electrochemical reduction of CO₂ to multicarbon (C₂₊) products is attracting attention for the sustainable production of fuel and chemicals. Conventionally, electrolytes containing alkali cations are typically used; however, salt precipitation associated with these cations often hinders stable CO₂ electrolysis. Organic cations are promising alternatives to alkali cations. Herein, we conducted gaseous CO₂ electrolysis in aqueous solutions containing tetraalkylammonium cations in the absence of alkali cations to evaluate the effect of organic cations on C₂₊ formation. When tetramethylammonium cations were present as the only cation species besides protons, the faradaic efficiency for CO₂ reduction exceeded 89% across a broad current density range of 0.1–1 A cm⁻². In particular, C₂₊ formation was efficient under high total current density conditions, reaching a faradaic efficiency of 69.6% and a partial current density of 0.7 A cm⁻². By contrast, the use of larger cations such as tetraethylammonium and tetrapropylammonium cations resulted in lower ethylene selectivity. Numerical simulations based on the generalized modified Poisson–Nernst–Planck model suggested that the size of the tetraalkylammonium cations affects the electric field strength within the electric double layer, with smaller cations forming a stronger field that promotes ethylene formation.

Interfacial water, serving as a subtle yet powerful performance modulator, plays a pivotal role in various electrochemical technologies due to its unique configurations and dynamic properties. Especially in the past decade, advances in electrocatalyst research, experimental characterization and theoretical modeling have significantly deepened the understanding of interfacial water's role in electrocatalytic systems. These as-obtained insights not only elucidate the dynamic behavior and structural properties of interfacial water but also highlight its importance in optimizing reaction pathways and improving electrocatalytic performance. Therefore, the understanding and regulation of interfacial water is an important topic in electrocatalytic research, and motivated us to compile this review. This review starts with a thorough analysis of interfacial water's properties and behaviors relevant to the electrocatalysis including structural types, water networks, rigidity and molecular orientation. Then, the specific roles of interfacial water in electrocatalysis are subsequently analyzed and classified as a co-catalyst, a masking agent, a regulator of reaction intermediates, and an inducer of catalyst reconfiguration. Next, some advanced experimental characterization and computational methods are presented to collectively probe the interfacial water, which is critical to capture accurate structural information. Furthermore, we present a comprehensive overview of key strategies for modulating the properties and behaviors of interfacial water to enhance the electrocatalytic performance of representative reactions at the electrolyte and catalyst levels, with emphasis on the specific mechanisms behind these modulation approaches. Finally, we discuss current challenges and future opportunities in this field, aiming to inspire the design of more advanced electrocatalytic systems.

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Electrochemical valorisation of biomass to value-added chemical feedstocks holds great potential to reduce the reliance on fossil fuels and accelerate the realisation of a sustainable future. In this work, we show that hydrofuroin, an important feedstock for sustainable aviation fuels, can be selectively produced on a zinc (Zn) single-atom catalyst via the electrochemical furfural reduction reaction (FRR). Initial theoretical results show that the weak binding capability of a zinc (Zn) single-atom active center effectively suppresses the parasitic hydrogen evolution reaction (HER) while enabling fast desorption and dimerization of furfural radicals towards hydrofuroin formation, which was proved by our experimental validation. The catalyst, obtained by depositing zinc phthalocyanine on purified multi-walled carbon nanotubes, exhibits near-unity faradaic efficiency for hydrofuroin production in a wide potential window, e.g., −0.5 to −0.8 V_RHE. The kinetic study further provides mechanistic insights into hydrofuroin formation on the single-atom site. This catalyst can be integrated into a flow cell electrolyser to achieve highly efficient furfural conversion to sustainable fuel precursors, which is beneficial for biomass electrovalorisation to value-added green products and chemicals.