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Single-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO 2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN 2 O 2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO 2 to CH 4 with current density of 40 mA·cm -2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN 2 O 2 active sites are due to the proper elevated CH 4 and H 2 energy barrier and fine-tuned electronic structure of Cu active sites. Single-atom catalysts (SACs) are promising candidates to catalyze CO 2 reduction for the formation of high value hydrocarbons but most of the reactions yield CO. Here, the authors show a low-temperature calcining process to fabricate a carbon-dots-based SAC to efficiently convert CO 2 to methane.

The electroreduction of CO 2 is a promising technology for carbon utilization. Although electrolysis of CO 2 or CO 2 -derived CO can generate important industrial multicarbon feedstocks such as ethylene, ethanol, n -propanol and acetate, most efforts have been devoted to promoting C–C bond formation. Here, we demonstrate that C–N bonds can be formed through co-electrolysis of CO and NH 3 with acetamide selectivity of nearly 40% at industrially relevant reaction rates. Full-solvent quantum mechanical calculations show that acetamide forms through nucleophilic addition of NH 3 to a surface-bound ketene intermediate, a step that is in competition with OH – addition, which leads to acetate. The C–N formation mechanism was successfully extended to a series of amide products through amine nucleophilic attack on the ketene intermediate. This strategy enables us to form carbon–heteroatom bonds through the electroreduction of CO, expanding the scope of products available from CO 2 reduction. The electroreduction of CO 2 -derived CO is a promising technology for the sustainable production of value-added chemicals. Now, it is shown how C–N bonds can be formed electrochemically through CO electroreduction on a Cu surface in the presence of amines. The formation of acetamides is observed through nucleophilic addition to a ketene intermediate.

Direct converting low concentration CO 2 in industrial exhaust gases to high-value multi-carbon products via renewable-energy-powered electrochemical catalysis provides a sustainable strategy for CO 2 utilization with minimized CO 2 separation and purification capital and energy cost. Nonetheless, the electrocatalytic conversion of dilute CO 2 into value-added chemicals (C 2+ products, e.g., ethylene) is frequently impeded by low CO 2 conversion rate and weak carbon intermediates’ surface adsorption strength. Here, we fabricate a range of Cu catalysts comprising fine-tuned Cu(111)/Cu 2 O(111) interface boundary density crystal structures aimed at optimizing rate-determining step and decreasing the thermodynamic barriers of intermediates’ adsorption. Utilizing interface boundary engineering, we attain a Faradaic efficiency of (51.9 ± 2.8) % and a partial current density of (34.5 ± 6.4) mA·cm −2 for C 2+ products at a dilute CO 2 feed condition (5% CO 2 v/v), comparing to the state-of-art low concentration CO 2 electrolysis. In contrast to the prevailing belief that the CO 2 activation step ( C O 2 + e − + * → C O 2 − * ) governs the reaction rate, we discover that, under dilute CO 2 feed conditions, the rate-determining step shifts to the generation of *COOH ( C O 2 − * + H 2 O → C * O O H + O H − ( a q ) ) at the Cu 0 /Cu 1+ interface boundary, resulting in a better C 2+ production performance. The development of catalysts that operate under low concentration CO 2 resembling industrial waste gases holds promise for CO 2 reduction. Here, the authors report a vacuum calcination approach for regulating the Cu 0 /Cu 1+ density on Cu-based catalysts that can electro-catalyze low-concentration CO 2 .

C–C coupling is of utmost importance in the electrocatalytic reduction of CO 2 , as it governs the selectivity of diverse product formation. Nevertheless, the difficulties to directly observe C–C coupling pathways at a specific nanocavity hinder the advances in catalysts and electrolyzer design for efficient high-value hydrocarbon production. Here we develop a nano-confined Raman technology to elucidate the influence of the local electric field on the evolution of C–C coupling intermediates. Through precise adjustments to the Debye length in nanocavities of a copper catalyst, the overlapping of electrical double layers drives a transition in the C–C coupling pathway at a specific nanocavity from *CHO–*CO coupling to the direct dimerization of *CO species. Experimental evidence and simulations validate that a reduced potential drop across the compact layer promotes a higher yield of CO and promotes the direct dimerization of *CO species. Our findings provide insights for the development of highly selective catalyst materials tailored to promote specific products. Precisely tunning the C–C coupling pathway through local microenvironments remains somewhat unclear. Here, the authors developed a nano-confined Raman spectroscopic strategy to uncover how the local electric field regulates the evolution of C–C coupling intermediates at a specific nanocavity.

Mathematical modelling is an indispensable tool to support water resource recovery facility (WRRF) operators and engineers with the ambition of creating a truly circular economy and assuring a sustainable future. Despite the successful application of mechanistic models in the water sector, they show some important limitations and do not fully profit from the increasing digitalisation of systems and processes. Recent advances in data-driven methods have provided options for harnessing the power of Industry 4.0, but they are often limited by the lack of interpretability and extrapolation capabilities. Hybrid modelling (HM) combines these two modelling paradigms and aims to leverage both the rapidly increasing volumes of data collected, as well as the continued pursuit of greater process understanding. Despite the potential of HM in a sector that is undergoing a significant digital and cultural transformation, the application of hybrid models remains vague. This article presents an overview of HM methodologies applied to WRRFs and aims to stimulate the wider adoption and development of HM. We also highlight challenges and research needs for HM design and architecture, good modelling practice, data assurance, and software compatibility. HM is a paradigm for WRRF modelling to transition towards a more resource-efficient, resilient, and sustainable future.

HighlightsCovalent organic frameworks (COFs) show enormous potential for building high-performance electrochemical sensors due to their high porosity, large specific surface areas, stable rigid topology, ordered structures, and tunable pore microenvironments.The basic properties, monomers, and general synthesis methods of COFs in the electroanalytical chemistry field are introduced, with special emphasis on their usages in the fabrication of chemical sensors, ions sensors, immunosensors, and aptasensors.The emerged COFs in the electrochemiluminescence realm are thoroughly covered along with their preliminary applications.Covalent organic frameworks (COFs), a rapidly developing category of crystalline conjugated organic polymers, possess highly ordered structures, large specific surface areas, stable chemical properties, and tunable pore microenvironments. Since the first report of boroxine/boronate ester-linked COFs in 2005, COFs have rapidly gained popularity, showing important application prospects in various fields, such as sensing, catalysis, separation, and energy storage. Among them, COFs-based electrochemical (EC) sensors with upgraded analytical performance are arousing extensive interest. In this review, therefore, we summarize the basic properties and the general synthesis methods of COFs used in the field of electroanalytical chemistry, with special emphasis on their usages in the fabrication of chemical sensors, ions sensors, immunosensors, and aptasensors. Notably, the emerged COFs in the electrochemiluminescence (ECL) realm are thoroughly covered along with their preliminary applications. Additionally, final conclusions on state-of-the-art COFs are provided in terms of EC and ECL sensors, as well as challenges and prospects for extending and improving the research and applications of COFs in electroanalytical chemistry.

Stimuli-responsive biomaterials that contain logic gates hold great potential for detecting and responding to pathological markers as part of clinical therapies. However, a major barrier is the lack of a generalized system that can be used to easily assemble different ligand-responsive units to form programmable nanodevices for advanced biocomputation. Here we develop a programmable polymer library by including responsive units in building blocks with similar structure and reactivity. Using these polymers, we have developed a series of smart nanocarriers with hierarchical structures containing logic gates linked to self-immolative motifs. Designed with disease biomarkers as inputs, our logic devices showed site-specific release of multiple therapeutics (including kinase inhibitors, drugs and short interfering RNA) in vitro and in vivo. We expect that this ‘plug and play’ platform will be expanded towards smart biomaterial engineering for therapeutic delivery, precision medicine, tissue engineering and stem cell therapy.A programmable polymer library that responds to external and internal stimuli has been developed and used to fabricate a series of nanocarriers for drug release. The carriers respond to disease biomarkers, triggering self-immolative motifs and leading to the site-specific release of therapeutics both in vitro and in vivo.

The recognition of cancer cells is a key for cancer diagnosis and therapy, but the specificity highly relies on the use of biorecognition molecules particularly antibodies. Because biorecognition molecules suffer from some apparent disadvantages, such as hard to prepare and poor storage stability, novel alternatives that can overcome these disadvantages are highly important. Here we present monosaccharide-imprinted fluorescent nanoparticles (NPs) for targeting and imaging of cancer cells. The molecularly imprinted polymer (MIP) probe was fluorescein isothiocyanate (FITC) doped silica NPs with a shell imprinted with sialic acid, fucose or mannose as the template. The monosaccharide-imprinted NPs exhibited high specificity toward the target monosaccharides. As the template monosaccharides used are over-expressed on cancer cells, these monosaccharide-imprinted NPs allowed for specific targeting cancer cells over normal cells. Fluorescence imaging of human hepatoma carcinoma cells (HepG-2) over normal hepatic cells (L-02) and mammary cancer cells (MCF-7) over normal mammary epithelial cells (MCF-10A) by these NPs was demonstrated. As the imprinting approach employed herein is generally applicable and highly efficient, monosaccharide-imprinted NPs can be promising probes for targeting cancer cells.

Surface‐enhanced Raman scattering (SERS) is among the most widely applied analytical techniques due to its easy execution and extreme sensitivity. Target molecules can be detected and distinguished based upon the fingerprint spectra that arise when absorbed on the SERS substrates surface, particularly on the SERS‐active hotspots. Thus, rational fabricating the enhancing substrates plays a key role in broadening SERS application. Programmable DNA functionalized plasmonic nanoassemblies, where DNA acts as both structure basis and functional unit, combine the specificity of DNA recognition, and modulate the assembly of plasmonic nanoparticles (NPs). Specifically designed DNA not only improves the selectivity to target molecules but also promotes the sensitivity of the optical signals through precisely regulating the distance between the molecule and the substrate. A variety of DNA‐functionalized SERS sensors have been reported and obtained well performance in the analysis of heavy metal ions in water, toxins, pesticide residues, antibiotics, hormones, illicit drugs, or other small molecules. This review places an emphasis on the design and sensing strategies of the DNA‐functionalized plasmonic nanoassemblies, as well as basic principles of Raman enhancement, and recent advances for environmental analysis. The current challenges and potential trends in the development of DNA‐functionalized SERS sensors for environmental pollutant monitoring in complicated scenarios are subsequently discussed. This review places an emphasis on the introduction of the programmable DNA‐functionalized plasmonic nanoassemblies as SERS sensors for environmental analysis, where the specifically designed DNA acts as both structure basis and functional unit, combining the specificity of DNA recognition and the sensitivity of SERS detection via modulating the assembly of plasmonic nanoparticles.

Electrochemiluminescence (ECL) analysis has become a powerful tool in recent biomarker detection and clinic diagnosis due to its high sensitivity and broad linear range. To improve the analytical performance of ECL biosensors, various advanced nanomaterials have been introduced to regulate the ECL signal such as graphene, gold nanomaterials, and quantum dots. Among these nanomaterials, some plasmonic nanostructures play important roles in the fabrication of ECL biosensors. The plasmon effect for the ECL signal includes ECL quenching by resonant energy transfer, ECL enhancement by surface plasmon resonance enhancement, and a change in the polarized angle of ECL emission. The influence can be regulated by the distance between ECL emitters and plasmonic materials, and the characteristics of polarization angle-dependent surface plasmon coupling. This paper outlines the recent advances of plasmonic based ECL biosensors involving various plasmonic materials including noble metals and semiconductor nanomaterials. The detection targets in these biosensors range from small molecules, proteins, nucleic acids, and cells thanks to the plasmonic effect. In addition to ECL biosensors, ECL microscopy analysis with plasmonic materials is also highlighted because of the enhanced ECL image quality by the plasmonic effect. Finally, the future opportunities and challenges are discussed if more plasmonic effects are introduced into the ECL realm.