EES catalysis最新文献

Co-based perovskite oxides are intensively studied as promising catalysts for electrochemical water splitting in an alkaline environment. However, the increasing Co demand by the battery industry is pushing the search for Co-free alternatives. Here we report a systematic study of the Co-free layered perovskite family RBaCuFeO_5+δ (R = 4f lanthanide), where we uncover the existence of clear correlations between electrochemical properties and several physicochemical descriptors. Using a combination of advanced neutron and X-ray synchrotron techniques with ab initio DFT calculations we demonstrate and rationalize the positive impact of a large R ionic radius in their oxygen evolution reaction (OER) activity. We also reveal that, in these materials, Fe³⁺ is the transition metal cation the most prone to donate electrons. We also show that similar R³⁺/Ba²⁺ ionic radii favor the incorporation and mobility of oxygen in the layered perovskite structure and increase the number of available O diffusion paths, which have an additional, positive impact on both, the electric conductivity and the OER process. An unexpected result is the observation of a clear surface reconstruction exclusively in oxygen-rich samples (δ > 0), a fact that could be related to their superior OER activity. The encouraging intrinsic OER values obtained for the most active electrocatalyst (LaBaCuFeO_5.49), together with the possibility of industrially producing this material in nanocrystalline form should inspire the design of other Co-free oxide catalysts with optimal properties for electrochemical water splitting.

Enzyme biocatalysis is reshaping pharmaceutical synthesis, offering sustainable and efficient pathways for drug discovery and production. This paradigm shift towards eco-friendly methodologies addresses concerns inherent in traditional chemical synthesis. Enzymes, celebrated for their precision and adaptability to mild conditions, are poised as ideal candidates for pharmaceutical applications. Their versatility facilitates the synthesis of diverse pharmaceutical compounds, ensuring precise drug design and minimizing environmental impact. The integration of multidisciplinary approaches, including protein engineering, computational biology, and nanoarchitectonics, holds the potential to propel enzyme biocatalysis even further. Protein engineering utilizes directed evolution and rational design to customize enzymes, enhancing their stability and efficacy. Computational biology aids in deciphering enzymatic mechanisms, while nanoarchitectonics introduces innovative enzyme integration strategies into continuous flow systems. This comprehensive review explores how these multidisciplinary approaches can revolutionize pharmaceutical research and production. The synergy among these disciplines promises to expedite pharmaceutical processes, promote sustainability, optimize efficiency, and elevate precision—aligning perfectly with the evolving requirements of the pharmaceutical industry.

Electrochemical reduction of CO₂ (CO₂RR) is an attractive technology to reintegrate the anthropogenic CO₂ back into the carbon cycle driven by a suitable catalyst. This study employs highly efficient multi-carbon (C₂₊) producing Cu₂O nanocubes (NCs) decorated with CO-selective Au nanoparticles (NPs) to investigate the correlation between a high CO surface concentration microenvironment and the catalytic performance. Structure, morphology and near-surface composition are studied via operando X-ray absorption spectroscopy and surface-enhanced Raman spectroscopy, operando high-energy X-ray diffraction as well as quasi in situ X-ray photoelectron spectroscopy. These operando studies show the continuous evolution of the local structure and chemical environment of our catalysts during reaction conditions. Along with its alloy formation, a CO-rich microenvironment as well as weakened average CO binding on the catalyst surface during CO₂RR is detected. Linking these findings to the catalytic function, a complex compositional interplay between Au and Cu is revealed in which higher Au loadings primarily facilitate CO formation. Nonetheless, the strongest improvement in C₂₊ formation appears for the lowest Au loadings, suggesting a beneficial role of the Au–Cu atomic interaction for the catalytic function in CO₂RR. This study highlights the importance of site engineering and operando investigations to unveil the electrocatalyst's adaptations to the reaction conditions, which is a prerequisite to understand its catalytic behavior.

Photocatalytic technology stands as a promising solution to address the current energy and environmental challenges. Halide perovskites, particularly lead-free double halide perovskites, have garnered recognition as next-generation photocatalysts due to their adjustable bandgap, low binding energy, broad visible light absorption range, and efficient charge carrier transfer. In this review, we explore the utilization of lead-free double halide perovskites characterized by their non-toxic attributes and diverse chemical compositions and properties as photocatalysts for both hydrogen production and carbon dioxide reduction. We commence by presenting an overview of lead-free double halide perovskites, followed by a comprehensive analysis of recent research outcomes pertaining to their application as photocatalysts for hydrogen production and carbon dioxide reduction. Lastly, we discuss the challenges and prospects associated with lead-free double halide perovskite photocatalysts. This review is anticipated to serve as a valuable reference for the development of lead-free double halide perovskite-based photocatalysts, addressing critical aspects in the pursuit of achieving high-efficiency hydrogen generation and carbon dioxide reduction, crucial for our future energy and environmental needs.

Electrochemical CO₂ reduction is an effective pathway to convert CO₂ into valuable fuels and chemicals, which provides a potential alternative to fossil fuel resources and plays a notable role in mitigating environmental issues and energy crises. The feasibility of the CO₂ reduction reaction (CO₂RR) hinges on the development of catalysts that feature high activity, selectivity, and stability. As a new research frontier, single-atom catalysts (SACs) have shown immense potential in the field of CO₂ reduction by virtue of their unique geometric/electronic structures, and have also provided new opportunities for atomic-level understanding of structure–function relationships. Therefore, this review aims to outline recent advances of SACs for CO₂RR. We start by introducing the current research status and general synthesis strategies of SACs, and then shift our focus to analyzing the various regulation strategies and deciphering the structure–function relationships of SACs in the CO₂RR. Finally, we propose future directions and opportunities for CO₂RR-oriented SACs, while also highlighting potential challenges that may be encountered along the way.

Hydrocracking polyolefins using bifunctional metal–zeolite catalysts is a pivotal strategy for the catalytic upcycling of plastic waste to produce value-added fuels. However, the macro-molecular size and stable C–C bond of polyolefins impose major challenges on catalyst design based on noble metal and microporous zeolites. The lack of investigation into the nanoscale proximity between Pt and USY has hindered the development of an evolving generation of catalysts. Herein, we report Pt/USY prepared by colloid-immobilization method with Pt nanoparticles exclusively located on the surface of USY is a superior catalyst (>50% higher activity) compared to its analogues that have Pt inside or away from USY crystalline, reaching a selectivity to gasoline (C_5–12) over 90%. The formation rate of liquid products reaches 6122 g_liquid g_Pt⁻¹ h⁻¹ and 5048 g_liquid g_Pt⁻¹ h⁻¹ in hydrocracking polyethylene (PE) and polypropylene (PP) at 280 °C, respectively. The hydrocracking of model alkanes with different molecular sizes demonstrates the nanoscale Pt-USY proximity as a key criterion in optimizing the accessibility and acidic environment of Pt, and the diffusion distance between metal and acid sites. These findings comprise a significant step forward toward rational catalyst design aiming at upcycling plastic waste for sustainable fuel production.

The electrochemical reduction of carbon dioxide to valuable fossil-free products opens up a way to close the carbon cycle, if based solely on renewable energy sources. Making the process industrially viable, however, needs high CO₂ conversion rates, efficient electrodes, and high selectivity for desired products. To reach this goal, highly catalytically active porous electrodes with maximized surface areas are required. We combined pulsed electrochemical deposition of the Ag foam catalyst with ionomer infiltration of the electrode to produce Ag-based gas diffusion electrodes (GDEs) in a facile and fast production process. Using the dynamic hydrogen bubble templation method (DHBT), we utilized the parasitic hydrogen evolution reaction (HER) to aid the solvent free structuring of the 3D catalyst network and directly manufacture a GDE. Different deposition parameters and in particular pulse-to-pause ratios increased the amount of deposited catalyst and successfully reduced the overpotential during CO₂RR operation. To inhibit electrode flooding and decrease CO₂ mass transport limitations during CO₂RR, we further infiltrated the electrode with a suitable perfluorosulfonic acid ionomer. SEM and EDS analyses showed a homogeneous Ag/F distribution along the cross section of the electrodes. These electrodes catalyzed the conversion of CO₂ to CO at industrially viable current densities of 500 mA cm⁻² with an unprecedented faradaic efficiency up to 76% in 1 M KHCO₃.

Green hydrogen production through water electrolysis is considered the next-generation technology capable of industrial-scale hydrogen production to achieve carbon neutrality. The core of constructing a water electrolyzer lies in designing the membrane electrode assembly (MEA) with optimal integration of the membrane, electrocatalysts, and gas diffusion layer. Among the two representative MEA fabrication methods, catalyst-coated substrates (CCS) and catalyst-coated membranes (CCM), CCM shows great promise due to its catalyst layer/membrane interface contact and scalability. The key factor in the CCM method is the effective application of the powdered catalyst onto the membrane. In this respect, the utilization of single-atom catalysts (SACs) has emerged as a noteworthy focus due to their unprecedented catalytic activity resulting from unique electronic/atomic configurations and high atomic utilization efficiency. Incorporating SACs into CCM–MEA has the potential to be a cutting-edge water electrolysis technology. However, it is still in its infancy due to the instability of the components (SACs, membranes, ionomers, supports) and degradation during the SACs–CCM–MEA fabrication and cell operation. Herein, we outline the representative fabrication method of MEA and provide a comprehensive analysis of SACs applicable to MEA. Then, we discuss the advantages of SACs–CCM–MEA and the challenges for industrial hydrogen production. Finally, this review concludes with future perspectives on the development of single-atom catalyst-coated membranes and the expected achievements.

Currently, computational models based on density functional theory (DFT) are intensively used for the analysis of electrocatalytic reactions and the design of enhanced catalysts. As the accuracy of these models is subjected to the quality of the input data, knowing the intrinsic limitations of DFT is crucial to improve computational predictions. A common pitfall of DFT is the estimation of the total energies of molecules, particularly those containing double and triple bonds. In this review, we show how gas-phase errors permeate thermodynamic and kinetic models of customary use in electrocatalysis, potentially compromising their predictiveness. First, we illustrate how these errors can be identified and provide a list of corrections for common molecules and functional groups. Subsequently, we explain how the errors spread from simple reaction energy calculations to adsorption energies, scaling relations, equilibrium potentials, overpotentials, and Sabatier-type activity plots. Finally, we list the remaining challenges toward an improved assessment of energetics at solid–gas–liquid interfaces.

Ammonia (NH₃) is an indispensable industrial chemical used in fertilizer production and energy carriers. However, its production through the Haber–Bosch process requires high temperature and high pressure, consuming significant energy and releasing large amounts of CO₂, rendering it unsustainable. As a result, sustainable approaches for ammonia synthesis powered by renewable electricity have gained significant attention, such as the electrocatalytic N₂ reduction reaction (N₂RR) and nitrate reduction reaction (NitRR). This review summarizes recent advancements in the design strategies of electrocatalysts for the NitRR, highlighting synthetic methods such as doping, alloying, single-atom engineering, nanoconfinement, size-regulation, and tandem catalysis. These strategies aim to tune the adsorption of reactants and intermediates or enhance proton–electron transfer. Future studies could explore new electrocatalysts for efficient NitRR based on the strategies summarized in this review to improve nitrate pollution removal efficiency and ammonia production rates. Furthermore, the challenging questions raised at the end of the paper, such as optimizing the reaction kinetics of the NitRR and improving catalyst selectivity and stability, can provide new directions and insights for future catalyst design.