Prospects of Single Atom-Based Electrified Membrane for Environmental Applications.

Modification of conductive electrodes with chemically tunable molecular catalysts represents an interesting and relatively unexplored area of photoelectrocatalysis research. Here, we report an investigation of the electrochemical behavior of graphene nanoribbons (GNR) deposited onto a glassy carbon electrode using π−π stacking interactions. Using the bipyrimidine moiety on the nanoribbon edges as a reporter of the proton-coupled electron transfer chemistry, we illustrate that the simple electrochemical treatment of as-deposited nanoribbon generates a hybrid material that is in strong electronic communication with the conductive support.1 This work shows a strategy for modifying the basal plane of carbon materials and provides a potential platform for the incorporation of catalytic metal sites via coordination through the N-functionalities of GNR.We also investigate the coordination of Rh-based hydrogen evolution reaction catalyst onto the edges of GNRs to form metal-nanoribbon catalyst (Rh-GNR).2 The electrocatalytic hydrogen evolution reaction was observed when glassy carbon electrode is modified by Rh-GNR to form Rh-GNR@GC. The catalytic activity is maintained throughout the entire pH region, which contrasts the behavior of the homogeneous (molecular) analog catalyst, which becomes inactive in the basic pH. The Rh K-edge X-ray absorption spectroscopy reveals that the molecular analog and Rh-GNR exhibit identical coordination environment, indicating that the differences in electrochemical behavior do not arise due to functional group differences between the two catalysts. The effect of interfacial electric fields on the catalytic sites was evaluated by monitoring the proton-coupled electron transfer chemistry and in situ X-ray absorption. The results of this work indicate that the catalytic sites are located outside the electric double layer and that the observed catalytic enhancements are not associated with field-driven chemistry. The observed improvements for the immobilized catalyst are instead assigned to the prevention of undesired catalyst aggregation when it is attached to the electrode surface.(1) Zoric, M. R.; Askins, E. J.; Qiao, X.; Glusac, K. D. Strong Electronic Coupling of Graphene Nanoribbons onto Basal Plane of a Glassy Carbon Electrode, ACS Appl. Electron. Mater. 2021, 3 (2), 854-860.(2) Askins, E. J.; Navabi, P.; Kumar, K.; Finkelmeyer, S. J.; Presselt, M.; Cabana, J.; Glusac, K. D. Interfacial Electrochemistry of Catalyst-Coordinated Graphene Nanoribbons, J. Am. Chem Soc. 2024, 146, 32, 22360.

Irreversible inhibition of glucose-6-phosphate dehydrogenase by the coenzyme A conjugate of ketoprofen: A key to oxidative stress induced by non-steroidal anti-inflammatory drugs?

Aeration accounts for 35-51% of the overall energy consumption in wastewater treatment processes and results in an annual energy consumption of 5-7.5 billion kWh. Herein, a solar-powered continuous-flow device was designed for aeration-free in situ Fenton-like reactions to treat wastewater. This system is based on the combination of TiO2-x/W18O49 featuring heterophase oxygen vacancy interactions with floating reduced graphene/polyurethane foam, which produces hydrogen peroxide in situ at the rates of up to 4.2 ppm h-1 with degradation rates of more than 90% for various antibiotics. The heterophase oxygen vacancies play an important role in the stretching of the O-O bond by regulating the d-band center of TiO2-x/W18O49, promoting the hydrogenation of *·O2- or *OOH by H+ enrichment, and accelerating the production of reactive oxygen species by spontaneous adsorption of hydrogen peroxide. Furthermore, the degradation mechanisms of antibiotics and the treatment of actual wastewater were thoroughly investigated. In short, the study provides a meaningful reference for potentially undertaking the "aeration-free" in situ Fenton reaction, which can help reduce or even completely eradicate the aeration costs and energy requirements during the treatment of wastewater.

Photocatalytic conversion of CO2 to value-added chemicals, a potential route to addressing the depletion of fossil fuels and anthropogenic climate change, is greatly limited by the low-efficient semiconductor photocatalyst. The integration of cocatalyst with light-harvesting semiconductor is a promising approach to enhancing the photocatalytic performance in CO2 reduction reaction. The enhancement is greatly determined by the catalytic active sites on the surface of cocatalyst. Herein, we demonstrate that the photocatalytic performance in the CO2 reduction reaction is greatly promoted by twin defects engineered Pd cocatalyst. In this work, Pd nanoicosahedrons with twin defects were in situ grown on C3N4 nanosheets, which effectively improve the photocatalytic performance in reduction of CO2 to CO and CH4 in comparison with Pd nanotetrahedrons without twin defects. It is proposed that the twin boundary (TB) terminations on the surface of Pd cocatalysts are highly catalytic active sites for CO2 reduction reaction. Based on the proposed mechanism, the photocatalytic activity and selectivity in CO2 reduction were further advanced through reducing the size of Pd icosahedral cocatalyst resulted from the increased surface density of TB terminations. The defect engineering on the surface of cocatalyst represents a novel route in realizing high-performance photocatalytic applications.

Heterogeneous catalysis is important in fine-chemical and pharmaceutical manufacture and in petroleum refining1. Many of the catalysts used by these industries are based on aluminosilicates, which combine high stability with excellent activity in acid-mediated reactions2. Within this class of material, zeolites — microporous crystalline aluminosilicates with three-dimensional framework structures — have attracted particular attention: they are significantly more active than the layered structures (clays)3 and mesoporous structures (whose walls are amorphous)4,5, and they impart shape selectivity on the reaction products. The selectivity arises from the fact that the catalytically active acid sites have to be accessed through uniformly sized pores and voids, imposing size constraints on the accessibility to reactants and the nature of the intermediates and products1. Providing access for larger molecules to the catalytic sites would expand the range of reactions that zeolites can catalyse. But attempts to increase the pore size of zeolites6 have met with only limited success. Here we describe an approach in which a layered zeolite precursor7,8 is delaminated, in much the same way as the layered structure of a clay may be unbound. The result is an aluminosilicate whose zeolite-type catalytic sites are contained within thin, readily accessible sheets. Performance tests show that the delamination process improves the accessibility of the catalytic sites without affecting their activity. We expect that our approach could be adapted to other layered zeolite precursors5,7,8,9,10,11, thus paving the way to exfoliated zeolite precursors as a new class of catalysts.

Conventional heterogeneous catalysts for CO2 conversion often face limitations in activity, selectivity, and stability under mild conditions, hindering their practical application and effective utilization of CO2. To address these challenges, this study presents a synergistic strategy integrating defect engineering and postsynthetic modification to fabricate metallized defective porous organic polymers (dPOP-OFe-X, X = 5, 10, 20) as efficient heterogeneous catalysts. Comprehensive characterization confirmed the controlled introduction of missing-linker −NH2 defects, the coexistence of imine and aminal linkages, and the successful anchoring of single-atom Fe3+ sites. Compared to nonmetallized counterparts, the dPOP-OFe-X catalysts exhibited significantly enhanced activity in both CO2/epoxide cycloaddition and CO2-mediated amine N-formylation under mild conditions. Specifically, the optimized dPOP-OFe-10 catalyst achieved a 93% yield of chloropropene carbonate from epichlorohydrin/CO2 (90 °C, 0.1 MPa, 8 h) and a 92% yield of N-methylformanilide from N-methylaniline/CO2 (100 °C, 1.0 MPa, 6 h). Additionally, dPOP-OFe-10 displayed broad substrate compatibility with diverse epoxides and amines, maintained high activity over five catalytic cycles, and retained structural integrity after recycling. Combined theoretical calculations and in situ FT-IR spectroscopy elucidated the interaction modes and energy profiles between catalytic sites and model reactants, revealing the synergistic catalytic mechanism involving multiple active sites in the CO2 cycloaddition reaction. This work establishes a practical and universal approach for designing high-performance catalysts via a defect engineering strategy, paving the way for efficient CO2 utilization.

Defect engineering and interface engineering are two efficient approaches to promote the electrocatalytic performance of transition metal oxides (TMOs) by modulating the local electronic structure and inducing a synergistic effect but usually require costly and complicated processes. Herein, a facile electrochemical etching method is proposed for the controllable tailoring of the defects in a three-dimensional (3D) open nanonetcage CoZnRuOx heterostructure via the in situ electrochemical etching to remove partial ZnO. The highly open 3D nanostructures, numerous defects, and multicomponent heterointerfaces endow the CoZnRuOx nanonetcages with more accessible active sites, moderated local electronic structure, and strong synergistic effect, thereby enabling them to not only deliver an ultralow overpotential (244 mV @ 10 mA cm-2) for oxygen evolution reaction (OER) but also high-performance overall water electrolysis by coupling with commercial Pt/C, with a potential of 1.52 V at 10 mA cm-2. Moreover, experiments and characterizations also reveal that the remaining Zn2+ can facilitate OH- adsorption and charge transfer, which also further improves the electrocatalytic OER performance. This work proposes a promising strategy for creating surface defects in heterostructured TMOs and provides insights to understand the defect- and interface-induced enhancement of OER electrocatalysis.

A “thermal-annealing vacancy-filling” synthesis strategy was developed to engineer cobalt single-atom catalysts (Co-MoS2/RGO) for exceptional hydrogen evolution reaction (HER) performance. By anchoring atomic Co onto Frenkel defect-engineered MoS2 nanosheets supported by reduced graphene oxide (RGO), we achieved simultaneous optimization of catalytic stability, electrical conductivity, and active site accessibility. The optimized Co3-MoS2/RGO hybrid demonstrates remarkable alkaline HER activity, requiring only 94.0 mV overpotential to achieve 10 mA cm−2 current density while maintaining excellent durability over extended operation. The atomically dispersed Co promoted HER kinetics through electronic structure modulation of MoS2 basal planes, creation of catalytic active centers, and defect-mediated synergies. The RGO further contributed to performance enhancement by preventing nanosheet aggregation, facilitating charge transfer, and exposing active sites. This defect engineering strategy provides a facile method for developing cost-effective, stable, and high-performance electrocatalysts for sustainable hydrogen production.

SARS-CoV-2 has aroused drastic effects on the global economy and public health. In response to this, personal protective equipment, hand hygiene, and social distancing have been considered the most important ways to prevent the direct spread of the virus. SARS-CoV-2 would be possible survive in wastewater for a few days, leading to secondary transmission via contact with water and wastewater. Thus, the most economical and practical approaches for decentralized wastewater treatment are renewable energies such as the solar energy disinfestation process. However, as freshwater requirements increase and fossil fuels become unsustainable, renewable energy becomes more attractive for desalination applications. Solar photovoltaic, membrane-based, and electricity desalination technologies are becoming increasingly popular due to their lower energy requirements. Several aquatic environments could be benefitted from solar energy wastewater disinfection. Besides, utilizing solar energy during the day can inactivate SARS-CoV-2 to nearly 90%. However, conventional membrane-based desalination practices have also been integrated, including reverse osmosis (RO) and electrodialysis (ED). Several exciting membrane processes have been developed recently, including membrane distillation (MD), pressure-reduced osmosis (PRO), and reverse electrodialysis (RED). Such operations can produce clean and sustainable electricity from brine and impaired water, generally considered hazardous to the environment. As a result, neither PRO nor RED can produce electricity without mixing a high salinity solution (such as seawater or brine and wastewater, respectively) with a low salinity solution. Herein, we critically review the progress in applying renewable energy such as solar energy and geothermal energy for generating electricity from wastewater treatment and uniquely discuss the effects of these two types of renewable energy on SARS-CoV-2 in air and wastewater treatment. We also highlight the significant process made on the membrane processes utilizing renewable energy and research gaps from the standpoint of producing clean and sustainable energy. The significant points of this review are: (1) among various types of renewable energy, solar energy and geothermal energy have been predominantly studied for wastewater treatment, (2) effects of these two types of renewable energy on SARS-CoV-2 in air and wastewater treatment are critically analyzed, and (3) the knowledge gaps and anticipated future research outlook have been consequently proposed thereof.

The endeavor toward photocatalytic CO2 fixation is largely hampered by the rigid spatial configurations and inadequate orbital overlap between the catalytic site and CO2. Herein, we propose a second-sphere coordination regulation strategy by atomically tailoring the metal-metal coordination of the secondary building unit (SBU). Amorphous metal-organic framework (a-MOF) is constructed as proof-of-concept to achieve creative control over the second coordination sphere. Such architecture transforms rigid trinuclear nodes into flexible dinuclear motifs. This shift can open spatial proximity to access the guest molecules and optimize s-π* overlap by enabling orbital reorientation. Both in situ experiments and theoretical calculations verify second-sphere engineering endows the Lewis base sites with high electron donating capacity and promotes the electron injection into the π* anti-bonding orbitals of the CO2 molecule effectively. Hence, the a-MOF displays approximately double the yield in various photocatalytic CO2 reactions compared with its crystalline counterpart. Moreover, its photo-assisted Li-CO2 battery delivers higher discharging voltage and a fourfold increment of discharge capacity at 200µA cm-2. The unique ability to tailor the secondary coordination sphere performs attractive merits governing the small molecule binding affinity, aiming to manipulate the local microenvironment of open metal sites for efficient CO2 fixation.

Pyrolyzed iron-based platinum group metal (PGM)-free nitrogen-doped single site carbon catalysts (Fe–NC) are possible alternatives to platinum-based carbon catalysts for the oxygen reduction reaction (ORR). Bimetallic PGM-free M1M2–NC catalysts and their active sites, however, have been poorly studied to date. The present study explores the active accessible sites of mono- and bimetallic Fe–NC and FeNi–NC catalysts. Combining CO cryo chemisorption, X-ray absorption and 57Fe Mössbauer spectroscopy, we evaluate the number and chemical state of metal sites at the surface of the catalysts along with an estimate of their dispersion and utilization. Fe L3,2-edge X-ray adsorption spectra, Mössbauer spectra and CO desorption all suggested an essentially identical nature of Fe sites in both monometallic Fe–NC and bimetallic FeNi–NC; however, Ni blocks the formation of active sites during the pyrolysis and thus causes a sharp reduction in the accessible metal site density, while with only a minor direct participation as a catalytic site in the final catalyst. We also use the site density utilization factor, ϕSDsurface/bulk, as a measure of the metal site dispersion in PGM-free ORR catalysts. ϕSDsurface/bulk enables a quantitative evaluation and comparison of distinct catalyst synthesis routes in terms of their ratio of accessible metal sites. It gives guidance for further optimization of the accessible site density of M–NC catalysts.

Advances in nanotechnology have positioned metal nanoparticles, especially gold (Au), iron (Fe) and silver (Ag), at the forefront of innovations in biomedical, environmental and catalytic applications. These qualities have enabled wide-ranging applications in wastewater cleanup, bio sensing, cancer treatment and antibacterial treatment. However, the synthesis method, structural characteristics, surface chemistry and colloidal stability of these nanoparticles significantly impact their performance and safety. This paper covers in detail the mechanics, benefits, drawbacks and environmental effects of both conventional and green synthesis techniques for creating Au, Fe and Ag nanoparticles. To illustrate their significance in determining nanoparticle size, shape, composition and surface functionality, key characterization techniques, including UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), forier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS) and zeta potential, are reviewed. The review also examines these nanoparticles' cytotoxicity to both healthy and malignant cells, as well as their antibacterial mechanisms, including membrane rupture, the production of reactive oxygen species (ROS) and biomolecular interference. Their functions in wastewater treatment are also investigated, with particular attention to catalytic reduction, heavy-metal removal, dye degradation and disinfection procedures. Significant obstacles still exist despite tremendous advancements, such as concerns about the toxicity of nanoparticles, their persistence in the environment, their economic viability and the scalability of green synthesis techniques. This analysis tackles existing gaps and proposes the creation of safer, more sustainable and application-oriented nanomaterials.

The first step of iron biomineralization mediated by ferritin is the oxidation at the ferroxidase active site of two ferrous ions to a diferric oxo/hydroxo species. Metal-loaded ferritin crystals obtained by soaking crystals of frog ferritin in FeSO(4) and CuSO(4) solutions followed by flash freezing provided X-ray crystal structures of the tripositive iron and bipositive copper adducts at 2.7 and 2.8 Å resolution, respectively. At variance with the already available structures, the crystal form used in this study contains 24 independent subunits in the asymmetric unit permitting comparison between them. For the first time, the diferric species at the ferroxidase site is identified in ferritins from higher eukaryotes. Anomalous difference Fourier maps for crystals (iron crystal 1) obtained after long soaking times in FeSO(4) solution invariantly showed diferric species with a Fe-Fe average distance of 3.1 ± 0.1 Å, strongly indicative of the presence of a μ-oxo/hydroxo bridge between the irons; protein ligands for each iron ion (Fe1 and Fe2) were also unequivocally identified and found to be the same in all subunits. For copper bound ferritin, dicopper(II) centers are also observed. While copper at site 1 is essentially in the same position and has the same coordination environment as Fe1, copper at site 2 is displaced toward His54, now acting as a ligand; this results in an increased intermetal distance (4.3 ± 0.4 Å). His54 coordination and longer metal-metal distances might represent peculiar features of divalent cations at the ferroxidase site. This oxidation-dependent structural information may provide key features for the mechanistic pathway in ferritins from higher eukaryotes that drive uptake of bivalent cation and release of ferric products at the catalytic site. This mechanism is supported by the X-ray picture obtained after only 1 min of soaking in FeSO(4) solutions (iron crystal 2) which reasonably contain the metal at different oxidation states. Here two different di-iron species are trapped in the active site, with intermetal distances corresponding to those of the ferric dimer in crystal 1 and of the dicopper centers and corresponding rearrangement of the His54 side chain.

Although various single-atom catalysts have been designed, atomically engineering their coordination environment remains a great challenge. Herein, a one-pot template-sacrificing pyrolysis approach is developed to synthesize well-defined Ni-N4-O catalytic sites on highly porous graphitic carbon for electrocatalytic CO2 reduction to CO with high Faradaic efficiency (maximum of 97.2%) in a wide potential window (-0.56 to -1.06 V vs RHE) and with high stability. In-depth experimental and theoretical studies reveal that the axial Ni-O coordination introduces asymmetry to the catalytic center, leading to lower Gibbs free energy for the rate-limiting step, strengthened binding with *COOH, and a weaker association with *CO. The present results demonstrate the successful atomic-level coordination environment engineering of high-surface-area porous graphitic carbon-supported Ni single-atom catalysts (SACs), and the demonstrated method can be applied to synthesize an array of SACs (metal-N4-O) for various catalysis applications.

<p>Energy systems of the future will be highly renewable, but building the required infrastructure will require vast amounts of materials. Particularly, renewable energy technologies are more copper-intensive than conventional ones and the production of this metal is intensive in energy and emissions. Moreover, as mineral resources are being depleted, more energy is required for their extraction, with subsequent increase in environmental impacts. Highly stressed and uncertain water resources only worsen this situation.</p><p>In this work, we will first provide a comprehensive review of the limited available energy planning approaches on copper mines, including transferrable learnings from other fields. Our second contribution is to compare the influence of different geographical locations on the optimal design of energy systems to supply the world’s main copper mines. For this, we use a linear energy system optimization model, whose main inputs are hourly time series for solar irradiation and power demand, and projections for energy technology costs and ore grade decline. Our third contribution is to propose a multi-vector energy system with novel demand-side management options, specific to copper production processes, including water demand management, illustrated on a case study in Chile (where mining uses a third of the nationwide electricity).</p><p>In the first part, the review, we learned that energy demand models in copper mines have only coarse temporal and operational resolutions, and require major improvements. Also, demand-side management options remain unstudied but could promise large potentials. In general, the models applied in copper energy planning seem overly simplistic when contrasted to available energy decision tools.</p><p>For the second part, we observed that in most locations, using local photovoltaic power not only lowers future electricity costs but also compensates for increased energy demand from ore grade decline. Some regions gain a clear competitive advantage due to extremely favorable climatic conditions.</p><p>In the third and final part, regarding the demand-side management, we saw how the geography and the spatial design of the mines strongly influence the available options and their performance. Jointly planning flexible water and energy supply seems to be particularly attractive. Also, there is space for smart scheduling of maintenance of the production lines, the hardness of the rock feed, oxygen production, and the hauling (rock transport) fleet.</p><p>As an outlook,  we highlight the need for consideration of lifecycle impacts as a design goal, and to further develop demand model’s and their flexibility on the mining side. We expect that implementing these smarter approaches will help secure a cleaner material supply for the global energy transition.</p>