Abstract Oxygen reduction reaction (ORR) is a kinetically sluggish reaction under uncatalyzed conditions. Numerous studies have revealed that mixtures of N-doped moieties in graphene improve ORR activity and selectivity. However, due to the surface heterogeneity of N-doped carbons, identifying the specific groups of the nitrogen moiety responsible for promoting ORR is challenging. In this study, we develop a structurally uniform electrochemical platform with well-defined nitrogen-containing terminal groups, including pyridazine, pyrimidine, pyridine, graphitic nitrogen, and amine. We uncover that pyridazine outperforms other nitrogen moieties in terms of ORR activity and product selectivity in a metal-free scenario, where pyridazine exhibits a 10-fold higher current density than the other nitrogen moieties. Our results demonstrate that ORR activity is greatly influenced by the solution pH and the steric and electronic environment of the nitrogen moiety, while ORR activity is unaffected by alkali and transition metal ions present in solution. This molecularly precise electrochemical model is envisioned to unveil unorthodox design principles that guide the development of new metal-free interfaces that catalyze ORR and other redox reactions involving proton-coupled electron transfer (PCET) steps that are instrumental to realizing a future sustainable society powered by alternative energy conversion schemes.

ABSTRACT Electrocatalytic conversion of C‐ and N‐containing pollutants into value‐added C–N‐bond containing compounds has attracted increasing attention. Specifically, the exploration centers on the generation of oximes featuring C═N bonds, which are essential chemicals with widespread applications in the pharmaceutical and fine chemical fields. Here, we develop an integrated electrocatalytic platform to produce formaldoxime as the target product in a green solvent using metal‐doped MoS 2 as efficient catalysts. Notably, Fe‐doped MoS 2 significantly boosts the Faradaic efficiency and yield rate for H 2 C═NOH to 81.2% and 963 mmol h −1 g −1 , respectively. Mechanistic studies reveal that the Fe dopants enhance the NO 2 – bonding, promoting substrate engagement and subsequently H 2 C═NOH formation in an aqueous medium. Upon incorporating into a flow electrolyzer, the yield rate for H 2 C═NOH electrosynthesis is drastically enhanced to 2630 mmol h −1 g −1 , almost triple that obtained from H‐cell setups. Our techno‐economic analysis estimates that the daily profit of this dual‐upgrading technology reaches $230 000+, highlighting the translational advantage of our strategy. Overall, this work establishes a non‐precious metal‐dopant strategy that upcycles low‐cost C‐ and N‐containing pollutants into valuable organonitrogens, enabling renewable energy synthesis of more valuable and functionally diverse commodities.

We developed a new hybrid bilayer membrane (HBM) platform, Fe(TPY)(CN)3 HBM, incorporating mononuclear Fe complexes chelated by tridentate 2,2':6',2''-terpyridine-4'-oxy-hexane-1-thiol (TPY) ligands and cyanide (CN–) ligands on an Au electrode, forming a stable and robust octahedral complex, covered by a monolayer of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipids, to study the transmembrane diffusion behaviours of monovalent cations, Li+, Na+, K+ and NH4+. The most positive shift in the half-wave potential (E1/2) of Fe3+/2+ redox occurred in presence of Li+, following the descending trend of Li+ > NH4+ > Na+ > K+. On the other hand, the Fe3+/2+ redox exhibited the largest peak separation (ΔE) in presence of Li+, which follows the same descending order. These trends highlight that the transmembrane diffusion mechanism for the monovalent cations studied is governed by interplay of charge density, intermolecular interactions, dehydration energy, and interfacial steric hindrance.

In this work, a laser-assisted nanomaterial preparation (LANP) method is utilized to fabricate Cu nanoparticles (NPs) supported on graphene. Because LANP is performed at room temperature and under ambient pressure, it enables the production of monodispersed Cu NPs supported on a few-layer graphene carbon network. These small Cu NPs (similar to 10 nm) exhibit the catalytic ability to reduce CO2 to HCOOH, CH3OH, CO, CH4, and C2H4. We study the graphene-supported Cu electrocatalysts as a function of the applied potential and find that CH4 is generated in high selectivity (85% Faradaic efficiency) at -2.4 V vs RHE. Furthermore, the selectivity of products can be tuned by the addition of a proton-conducting fluoropolymer (Nafion) overlayer of 2 or 15 mu m. The Cu NPs in conjunction with Nafion enhance C2H4 production through the dimerization of a Nafion-stabilized Cu-CO intermediate. Taken together, these results demonstrate that the LANP method can be used to construct CO2 reduction catalysts with a controlled selectivity.

Oxygen reduction reaction (ORR) plays a critical role in many electrochemical energy conversion devices including low-temperature fuel cells. However, the sluggish nature of ORR has impeded the commercialization of fuel cells with high efficiency and low costs. At present, platinum-based materials are commonly used as ORR electrocatalysts, but the high cost associated with precious metals has prompted researchers to seek alternative catalysts based on earth-abundant metals, such as copper, supported on nitrogen-doped carbon materials. In this work, we investigated the use of a dicopper complex of 3,5-diamino-1,2,4-triazole (CuDAT) as an inorganic-organic nanohybrid electrocatalyst for ORR before and after direct nanosecond pulsed laser augmentation at room temperature under an ambient atmosphere. Compared to the metal-free Vulcan carbon control, the CuDAT electrode after emission-free pulsed laser augmentation (PL-CuDAT) exhibited an increase in onset potential by 120 mV and an increase in product selectivity for H2O by approximately 58% to 97%. This study suggests that solid-to-solid pulsed laser augmentation could be an effective and green approach to improving the catalytic performance of electrocatalysts.

Although the effects of ligand interlocking on specific features of coordinated metal were first reported in 1980s', strategies to precisely control these features through structural modifications of interlocked ligands remains underdeveloped. This limitation has hindered the broader exploitation of this unique class of coordination compounds across various fields of transition metal chemistry. Through a systematic comparison and detail analysis of a series of CuI catenane complexes, we show in this work that the size of the interlocked rings and exocyclic substituents are important structural parameters that regulate the exposure of the metal coordination sphere, which also influences the coordination geometry, electronic structures, spectroscopic, photophysical and electrochemical properties, as well as thermodynamic stability, ligand exchange kinetics, and chemical reactivity of the coordinated metal. Relationship between the structural features of the catenane and the extent of these effects is also revealed. These insights not only faciliate the rational design of a new type of switchable catenane catalyst wherein the interlocked structure is preserved, but also establish new principles for leveraging the unique effects of mechanical interlocking for diverse applications involving coordination complexes.

While earth-abundant metals are green and sustainable alternatives to precious metals for catalytic chemical conversions, the fast ligand exchange involving most of the base metals renders their development into robust, reusable catalysts very challenging. Described in this work is a new type of heterogeneous catalyst derived from a 2D metal-organic layer (MOL) grafted with catenane-coordinated Cu(I) complexes. In addition to the good substrate accessibility, easy functionalization, and other favorable features due to the MOL support, the mechanical bond in the anchored catenane ligands also represents a new mechanism to dynamically confine the coordination environment and kinetically stabilize the coordinated Cu(I) to give a well-defined, active yet stable heterogeneous catalyst. Pilot catalytic studies using a model dehydrogenative C─O cross-coupling reaction showed that the Cu(I) catenane-grafted MOL led to exclusive formation of the C─O coupled product, whereas control catalysis using a similar Cu(I) catalyst supported by non-interlocked macrocyclic ligands was found to also give a C─C coupled by-product, whose formation was found to be mediated by the uncontrolled oxidation of the Cu(I) to Cu(II), highlighting the distinctive roles and untapped potential of the catenane coordination in developing base metal-derived catalysts for challenging catalytic conditions.

Upcycling C- and N-containing pollutants into value-added resources is key to achieving a sustainable society in the near future. In recent years, coelectrolysis powered by renewable energy sources to generate structurally complicated and functionally diverse C-N bonds is highly desirable yet more challenging compared with C-only or N-only reduction reactions. Oximes, which contain C=N bonds, are important precursors in medicine and the fine chemical industry. Previous attempts to coreduce carbon dioxide and nitrate or nitrite yielded formaldoxime (H2C=NOH) as a byproduct with low selectivity. Herein, we demonstrate a new tandem electrocatalytic pathway to produce H2C=NOH as the target product using NiFe layered double hydroxides (LDHs) as efficient catalysts. Upon expanding the interlayer spacing of NiFe LDH using dodecyl-sulfonate as an intercalating anion, this catalyst displays a record-high Faradaic efficiency for H2C=NOH of 31% in aqueous solution at -1.9 V vs reversible hydrogen electrode. Our findings also show that the lengths of alkyl chains can tune the immediate microenvironment surrounding the dual Ni-Fe active sites, thus boosting the C-N coupling yield rate. Kinetic isotopic effect studies and control experiments under H2 are further carried out to interrogate the electrocatalytic mechanism of this tandem C-N bond formation process. Overall, this study offers a compelling approach to form a C-N bond via a green electrosynthesis scheme in an aqueous medium. Furthermore, this study underscores the importance of precisely regulating the electrochemical microenvironment for enhancing the synergy between dual-metal active sites for efficient domino electrosynthesis.

Assembly of DNA nanostructures to sub-millimetre scales is expected to have significant potential for applications in materials science and medicine. One approach to control nanostructure growth is through using acoustic waves to create pressure nodes for clustering. Here, we report a facet-based underlying DNA nanostructure architecture with structural and stability characteristics ideal for acoustic patterning. The architecture comprises only 16 canonical DNA oligonucleotides which self-assemble to form a nested cube, inspired by the four-dimensional hypercube known as a "tesseract." Cryogenic electron microscopy (Cryo-EM) and atomic force microscopy (AFM) analysis revealed a fully formed tesseract structure with exceptional stiffness and a melting temperature of 84°C, significantly higher than other unmodified DNA nanostructures. The DNA tesseract nanostructures could be acoustically shaped into wires spanning over 500 µm, observed after deposition onto an interdigitated electrode (IDE). The wires were shown to be electrically conductive, highlighting unique prospects for application. Simplified bottom-up assembly of a small number of oligonucleotides into a relatively complex and structurally stable DNA nanostructure with characteristics ideal for modular assembly holds promise for applications across bioelectronics and other fields.

Electrocatalytic nitrate reduction reaction (NO3RR) for the selective generation of ammonia (NH3) enables the removal of deleterious nitrate pollutants while simultaneously upcycling them into a value-added fertilizer. The development of nonprecious metal-derived catalysts such as those featuring copper (Cu) as earth-abundant alternatives for the state-of-the-art precious metal catalysts is of urgent need yet suffering from the activity-selectivity-durability trilemma. Rational design of molecular Cu complexes with well-defined coordination structures permitting systematic structure-activity relationship (SAR) investigations is key to addressing the challenge. Here, a series of molecular Cu(I) complexes with [2]catenane ligands are developed as NO3RR electrocatalysts for the first time. By engineering multiple cationic ammoniums on the catenane backbone, acceptance of the anionic nitrate substrate as well as the release of the cationic ammonium product are promoted, thereby facilitating a higher Faradaic efficiency and product selectivity toward ammonia via an 8e- pathway. Of note, the mutual Coulombic repulsion between the multiply charged ligands is overcome by the mechanical interlocking such that the catalyst integrity can be maintained under practical conditions. This report highlights the promise of employing mechanically interlocked ligands as a platform for customizing metal complexes as catalysts for redox processes involving multiple proton-coupled electron transfer steps.

Despite notable advancements in noble metal photocatalysis, improving catalyst efficiency and recyclability remains a key challenge that needs to be addressed to facilitate large-scale synthetic applications. Herein, we have successfully synthesized bisphosphine-protected gold nanoclusters with a distinctive Johnson solid kernel, which serve as efficient and recyclable heterogeneous photocatalysts for visible-light-driven three-component radical couplings in Fukuyama indole synthesis. In contrast to conventional gold complexes, the newly developed cluster-based catalysts can be easily photoexcited to their triplet states by visible light, enabling single-electron transfer with O-acyl oximes, a hitherto unexplored class of electrophiles in gold photocatalysis. Our latest discovery suggests that establishing photocatalytic systems based on atomically precise metal nanoclusters with unique structural and electronic properties represents a promising avenue for advancing chemical synthesis in a sustainable and practical manner.

The conventional synthesis of nitrile requires demanding conditions involving high temperature and pressure with low yield and selectivity, highlighting the need for efficient C≡N formation strategy. Industrial wastes, such as alcohol and NH3, represent abundant and sustainable feedstocks for C–N commodities. Herein, we develop a highly efficient convergent strategy to upcycle C- and N-wastes into nitriles driven by renewable energy using non-precious metal catalyst featuring dual-active-site. An optimal Faradaic efficiency for acetonitrile achieves a record-high 67.9%. The product scope is further expanded to propionitrile, butyronitrile, and 2-(pyridin-3-yl)acetonitrile to demonstrate the broad applicability of our strategy. In addition, the overall electrosynthesis activity is further scaled up to 646.7 mmol⸳h–1⸳m–2 using a continuous-flow electrolyzer, demonstrating the feasibility and downstream translational potential of our strategy. This work pioneers a renewable energy-powered route for co-upgrading C- and N-wastes simultaneously into value-added C≡N platform chemicals, which is central to shifting the paradigm from linear consumption to circular manufacturing.

The traditional synthesis of commodities containing carbon and nitrogen requires high temperature, elevated pressure, and costly substrates, highlighting the need for renewable-energy-driven methods with affordable C,N sources. Food loss and waste (FLW) represents an abundant, nearly zero-cost resource containing readily accessible C-source that remains underutilized. Herein, by using dual-active-site non-precious metal catalyst, we demonstrate a strategy for electrocatalytic conversion of FLW into formamide, a highly sought-after organonitrogen compound containing valuable C–N bond. Initial validation with methanol achieves a Faradaic efficiency of 57.9% for formamide production. The substrate scope is extended to ethylene glycol (a major plastic waste component), glycerol (a biodiesel byproduct), and carbohydrates (from FLW). Based on these results, both solid and liquid wastes are employed into our strategy with promising yield rate (645, 349, and 73 mmol⸳h–1⸳g–1 from spoiled banana, banana peel, and expired milk). In-situ FTIR spectroscopy reveals a key nitrile intermediate, providing a deeper understanding of our FLW-to-feedstock process. This work pioneers a renewable energy-powered route for upgrading FLW to value-added C–N containing products, simultaneously addressing environmental pollution and enabling sustainable chemical synthesis from low-cost domestic and industrial wastes.

At present, over 95 % of H2O2 is produced via the anthraquinone process that requires large infrastructure, generates organic pollution, and poses safety issues. Electrochemical H2O2 generation through oxygen reduction can serve as an alternative, reliable, and decentralized production method if affordable and high-performance electrocatalysts can be developed. Herein, a two-step process is used to prepare an Fe-based complex as a non-precious metal electrocatalyst to facilitate oxygen reduction reaction (ORR) and produce an alkaline H2O2 solution. The Fe complex of benzene-1,3,5-tricarboxylate (FeBTC) is first synthesized using a hydrothermal method and then activated via a pulsed laser treatment process that is optimized via the Taguchi method. The pulse-laser-treated FeBTC (PL-FeBTC) lowers the H2O2 electrosynthesis overpotential by 50 mV at-0.1 mA/cm2 and exhibits a 25 % increase in H2O2 product selectivity at 0.4 V vs. RHE. The experimental results indicate that the O2-to-H2O2 turnover frequency and electrocatalytic yield of the Fe-based metal-organic framework are enhanced simultaneously through solid-to-solid pulsed laser conversion. Through a series of X-ray photoelectron spectroscopy, elemental analysis, Raman spectroscopy, X-ray absorption spectroscopy, and control atmospheric experiments, the origin of the improvement in catalytic performance is rationalized through the formation of an oxo-bridge across the di-Fe active site via an oxygen-doping mechanism, thus providing a systematic laser methodology for precise structure-performance tuning. Beyond H2O2 generation, this study further lays the foundation for the development of cost-effective and scalable electrocatalysts that are central to other commodity manufacturing and sustainable resourcification processes.

Active colloids with the ability to self-propel and collectively organize are emerging as indispensable elements in microrobotics and soft matter physics. For chemically powered colloids, their activity is often induced by gradients of chemical species in the particle's vicinity. The direct manipulation of these gradients, however, presents a considerable challenge, thereby limiting the extent to which active colloids can be controlled. Here, we introduce a series of rationally designed molecules, denoted as chemical auxiliary (CA), that intervene with specific chemical gradients and thus unveil new capabilities for regulating the behaviors of photocatalytic active colloids. We show that CA can alter the diffusiophoretic and osmotic interactions between active colloids and their subsequent self-organization. Also, CA can tune the self-propulsion of active particles, enabling a record high propulsion speed of over 100 μm/s and endowing high salt tolerance. Furthermore, CA is instrumental in establishing dynamic, competing gradients around active particles, which signifies an in situ, noninvasive, and reversible strategy for reconfiguring between modes of colloidal activity.

While Earth abundant metals are green and sustainable alternatives to precious metals for catalytic chemical conversions, the fast ligand exchange involving most of these metals renders their development into robust, reusable catalysts very challenging. Described in this work is a new type of heterogeneous catalyst derived from a 2D metal-organic layer (MOL) grafted with catenane-coordinated Cu(I) complexes. In addition to the good substrate accessibility, easy functionalization and other favorable features due to the MOL support, the anchored catenane ligands also provide a well-defined coordination environment and good kinetic stability to the coordinated Cu(I). Catalytic studies using phenols and bromodicarbonyls as the substrates showed that the Cu(I) catenane-grafted MOL resulted in the exclusive C–O coupling of the substrates, whereas a control catalyst in which the catenanes are replaced by non-interlocked macrocyclic ligands was found to lead to also a C–C coupling due to the uncontrolled formation of oxidized copper active site. The integration of mechanically interlocked catalyst to extended framework support thus represent an unexplored potential of exploiting labile, Earth-abundant metals for sustainable catalysis under challenging conditions.

Iron-sulfur (Fe-S) proteins play vital roles in multiple cellular processes, including mediating redox balance as well as DNA replication and repair. Given the role of Fe-S cofactors in genome maintenance, mutations in such metalloproteins could be associated with cancer. Nevertheless, only a few cancer-associated Fe-S proteins have been identified. In vitro , Fe-S cluster is susceptible to degradation in oxic environment. It could also be replaced by other metal ions during protein purification, mis-labelled as zinc finger or Zn-containing proteins. In silico , bioinorganic Fe-S cluster lacks unique sequence characteristics that distinguish itself from other metal-coordination sites, making motif prediction based solely on protein sequence difficult. Thus, in this study, three traits have been employed to discover putative cancer-associated 4Fe-4S proteins. Here, we have analyzed the human proteome via a three-pronged approach: (i) the presence of a triamino acid motif, (ii) the geometric arrangements of the cysteines, and (iii) the mutations of cancer-associated cysteines. In addition to MUTYH, a known 4Fe-4S human DNA glycosylase, 21 novel proteins were discovered as potential cancer-associated 4Fe-4S proteins. While 6 receptor proteins and 3 growth factors have been identified as potential targets in this study, 5 histone lysine methyltransferases with SET domains were also predicted to contain 4Fe-4S metallocofactors. This work provides insights for rational adjustments in experimental design and novel cancer biomarker discovery.### Competing Interest StatementThe authors have declared no competing interest.

Upon coordination to catenane ligands derived from interlocked macrocycles of different size, gradual deviation of the coordination structure of the resulting 4-coordinate copper(I) complexes from the preferred tetrahedral geometry is resulted, and such structural distortion represents a new mechanism for modulating the thermodynamic, kinetic, photophysical and electrochemical properties of the transition metal complexes via ligand mechanical interlocking. Results from this study hence not only first demonstrate that the extend of catenand effect on metal coordination properties can be tuned by a physical attribute characteristic to mechanical interlocking, but also are implicated in the reactivity and potential applications of a distinct, rarely studied class of transition metal complexes supported by mechanically bonded ligands.