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Solar‐driven photocatalysis employing particulate semiconductors represents a promising approach for sustainable production of valuable chemical feedstock. Metal poly(heptazine imide) (MPHI), a novel 2D ionic carbon nitride, has been recognized as an emerging photocatalyst with distinctive properties. In this minireview, we first delineate the forefront innovations of MPHI photocatalysts, spanning from synthetic strategies and solving structures to the exploration of novel properties. We place special emphasis on the structural design principles aimed at developing high‐performance MPHI systems toward photocatalytic solar fuel production such as H2 evolution, H2O oxidation, H2O2 production and CO2 reduction. Finally, we discuss crucial insights and challenges in leveraging highly active MPHIs for efficient solar‐to‐chemical energy conversion. [ABSTRACT FROM AUTHOR]

Solar‐driven photocatalysis employing particulate semiconductors represents a promising approach for sustainable production of valuable chemical feedstock. Metal poly(heptazine imide) (MPHI), a novel 2D ionic carbon nitride, has been recognized as an emerging photocatalyst with distinctive properties. In this minireview, we first delineate the forefront innovations of MPHI photocatalysts, spanning from synthetic strategies and solving structures to the exploration of novel properties. We place special emphasis on the structural design principles aimed at developing high‐performance MPHI systems toward photocatalytic solar fuel production such as H2 evolution, H2O oxidation, H2O2 production and CO2 reduction. Finally, we discuss crucial insights and challenges in leveraging highly active MPHIs for efficient solar‐to‐chemical energy conversion. [ABSTRACT FROM AUTHOR]

Controlled radical polymerization corresponds to variety of synthetic strategies that aim the generation of precise macromolecular architectures. Iodine transfer polymerization (ITP) is one of the oldest methods to conduct controlled radical polymerization; however, it seems to have lost visibility compared to other popular techniques. It relies on utilization of iodine species in reversible deactivation kinetics, and it has some significant advantages compared to other methods. Its simplicity, minimized toxicity, metal‐free nature, no coloring on final product, and ease of purification provide widespread applicability, even in industry. In this perspective, the basics of ITP are re‐introduced, and emerging technologies (heterophase polymerization, photoinitiation, and sustainability) in ITP are discussed. [ABSTRACT FROM AUTHOR]

A recent study published in the journal Nature has provided new insights into the charge-transfer processes that occur in photocatalytic reactions. The researchers used unique methods involving time-resolved and spatiotemporally resolved measurements to monitor these processes in Cu2O semiconductors. They found that quasi-ballistic inter-facet electron transfer and spatially selective trapping are the predominant processes that facilitate efficient charge separation in photocatalysts. This knowledge could lead to the development of high-performance semiconductors for various applications. The study utilized surface photovoltage microscopy and time-resolved photoemission electron microscopy to observe the charge-transfer processes spatially and temporally. [Extracted from the article]

Interfacial tension‐driven formation of intricate microparticle geometries from complex emulsions is presented in this work. Emulsion‐templating is a reliable platform for the generation of a diverse set of microparticles. Here, water‐in‐styrene‐in‐water complex emulsions undergo reproducible metamorphosis, i.e., from liquid state emulsions to solid structured microparticles are employed. In contrast to the traditional usage of glass‐based microfluidics, polydimethylsiloxane (PDMS) swelling behavior is employed to generate complex emulsions with multiple inner cores. In the presence of block copolymer surfactant, these emulsions undergo gravity‐driven dewetting of styrene, to transform into membranous structures with compartments. Further polymerization of styrene skeletal remains resulted in microparticles with interesting geometries and intact membranes. Mechanical and confocal microscopic studies prove the absence of polystyrene within these membranes. Using osmotic pressure, membrane rupture and release of encapsulated gold nanoparticles from such polymerized emulsions leading up to applications in cargo delivery and membrane transport are promoted. Even after membrane rupture, the structured microparticles have shown interesting light‐scattering behavior for applications in structural coloring and biosensing. Thereby, proving PDMS‐based swelling as a potential methodology for reproducible production of complex emulsions with a potential to be transformed into membranous emulsions or solid microparticles with intricate structures and multiple applications. [ABSTRACT FROM AUTHOR]

Sodium lignosulfonate (LS) was valorized to low molecular weight (Mw) fractions by combining solvothermal (SF) and catalytic hydrogenolysis/hydrogenation fragmentation (SHF) in a continuous flow system. This was achieved in either alcohol/H2O (EtOH/H2O or MeOH/H2O) or H2O as a solvent and Ni on nitrogen-doped carbon as a catalyst. The tunability according to the temperature of both SF and catalytic SHF of LS has been separately investigated at 150 °C, 200 °C, and 250 °C. In SF, the minimal Mw was 2994 g mol−1 at 250 °C with a dispersity (Đ) of 5.3 using MeOH/H2O. In catalytic SHF using MeOH/H2O, extremely low Mw was found (433 mg gLS−1) with a Đ of 1.2 combined with 34 mg gLS−1. The monomer yield was improved to 42 mg gLS−1 using dual catalytic beds. These results provide direct evidence that lignin is an unstable polymer at elevated temperatures and could be efficiently deconstructed under hydrothermal conditions with and without a catalyst. [ABSTRACT FROM AUTHOR]

Conductive polymers find key applications ranging from optoelectronics and OLEDs to conductive composite materials. The synthesis of conductive polymers from monomers, such as thiophene derivatives, pyrroles and aniline, mainly relies on oxidative polymerization, and the processing of so‐formed (insoluble) polymers is a major issue that needs to be addressed. In the present work, oxidative photopolymerization of 3,4‐ethylenedioxythiophene (EDOT) by visible light employing the metal‐free semiconductor graphitic carbon nitride (g‐CN) is presented. Two main reaction pathways based on g‐CN content are described, and the formation of processable oligo‐EDOT is demonstrated. [ABSTRACT FROM AUTHOR]

Natural polymers are attractive sustainable materials for production of fibers and composite materials. Cotton and flux are traditional plants used to produce textiles with comforting properties while technologies like Viscose, Lyocell and Ioncell-F allowed to extent fiber use into regenerated cellulose from wood. Neither natural nor man-made fibers completely satisfy the needs for cellulose based fabrics boosting development of new approaches to bring more sustainability into the fashion. Technologies like Spinnova are arising based on the spinning of mechanically pretreated cellulose materials with a lower environmental impact though challenged by the fiber quality and strength related to the inconsistency of the mechanical fibers. Nanoscaled cellulose is an excellent solution to improve the consistency of spin fibers, but charges introduced by traditional chemical treatments prevent rebuilding native hydrogen bonding and compromise the mechanical properties especially in wet conditions. We used nanocellulose with low surface charge isolated using reactive eutectic media to spin fibers able to restore the native hydrogen bonding and enable constitutional mechanical strength of cellulose. We performed un-optimized spinning to reveal the intrinsic properties of the fibers and confirmed the preserved strength of wet fibers compliant with the low surface charge enabling further engineering towards cotton-like fabric from wood. [ABSTRACT FROM AUTHOR]

A network of aqueous emulsion droplets that exhibits programmed and directional chemical inter-droplet communication is described. A non-reciprocal transfer of substrates between enzyme-containing aqueous emulsion droplets is realized by (biochemically) induced osmolarity gradients and concomitant concentration gradients are used to direct a multistep enzymatic cascade reaction across multiple droplets. [ABSTRACT FROM AUTHOR]

Complex aqueous emulsions represent a promising material platform for the encapsulation of cells, pharmaceuticals, or nutrients, for the fabrication of structured particles, as well as for mimicking the barrier-free compartmentalization of biomolecules found in living cells. Herein, we report a novel, simple, and scalable method of creating multicomponent aqueous droplets with highly uniform internal droplet morphologies that can be controllably altered after emulsification by making use of a thermal phase separation approach. Specifically, temperature-induced phase separation inside as-formed emulsion droplets comprising aqueous mixtures of two or more hydrophilic polymers allows for the generation of Janus and Cerberus emulsion droplets with adjustable internal morphologies that are solely controlled by a balance of interfacial tensions. We demonstrate our approach by applying both, microfluidic and scalable batch production, and present a detailed model study with predictive capabilities that enables fine-tuning and dynamically altering the droplet morphology as a function of types, molecular weights, and hydrophilicities of the polymers as well as the surfactant hydrophilic-lipophilic balance. The ability to rationally design complex aqueous emulsion droplets with previously unattainable dynamic control over their morphologies after emulsification entails the potential to design new responsive soft materials with implications for a variety of applications beyond encapsulation, including the design of complex adaptive and self-regulating materials, e.g. for chemical and biological sensing applications. [ABSTRACT FROM AUTHOR]

The year 2020 marks the 100th anniversary of the first article on polymerization, published by Hermann Staudinger. It is Staudinger who realized that polymers consist of long chains of covalently linked building blocks. Polymers have had a tremendous impact on the society ever since this initial publication. People live in a world that is almost impossible to imagine without synthetic polymers. But what does the future hold for polymer science? In this article, the editors and advisory board of Macromolecular Chemistry and Physics reflect on this question. [ABSTRACT FROM AUTHOR]

Humic acid, as a natural organic matter, is widely distributed in surface soil, oceans, rivers, and other ecological environments throughout the whole earth ecosystem. Humic acid provides abundant organic carbon and helps to maintain a hydrated, pH and redox buffered environment hosting the soil microbiome. Humic acid is however also a largely ignored polymer material full of exciting functional properties, and its scale is enormous. This perspective article discusses its synthesis and management as a tool to tackle parts of the climate crisis as well its use in technological applications, as made by chemical conversion of agricultural side products to artificial humic acids. [ABSTRACT FROM AUTHOR]

Molecular photoredox complexes from the platinum group paved the way of organic photocatalysis. However, high price and difficulties related to removal and recycling hamper application of such complexes on the larger scale. Carbon nitride semiconductor photocatalysts are deprived at large extent of such limitations. Herein, we summarize application of ionic carbon nitrides in photocatalysis. A salt‐like structure of ionic carbon nitrides comprising negatively charged poly(heptazine imide) anion and positively charged alkali metal cations gives rise to a number of unique properties and high activity in photocatalysis. The performance of ionic carbon nitrides in H2 generation is up to 100 times higher compared with the covalent graphitic carbon nitrides. Eleven photocatalytic reactions mediated by ionic carbon nitrides and their long‐lived radicals are reviewed. Economy of using carbon nitride photocatalysts in comparison with the photoredox complexes from the platinum group has been analyzed. [ABSTRACT FROM AUTHOR]

Abstract: A cost‐effective, straightforward, and environmentally benign alcohol iodination procedure with broad substrate scope is reported herein. In this reaction system, visible light and iodoform are employed as the energy source and iodination reagent, respectively. The reaction begins with the homolytic fission of the C–I bond in iodoform induced by visible‐light irradiation, producing active radicals. The following steps involve radical trapping by DMF (dimethylformamide), nucleophilic substitution, Vilsmeier‐type reagent formation, and the final iodination of the alcohol. The excellent performance of the model reaction in the flow photoreactor demonstrates the potential of this system for practical application. [ABSTRACT FROM AUTHOR]

Abstract: Water splitting to its elements, either by electrochemistry or by solar light, is among the most covered areas in nanostructured functional materials. This personal account article analyzes potential downstream translation problems and reviews alternative chemistries with a potential higher return. Liberation of oxygen for accepting the holes is a kinetically demanding half reaction afflicted with kinetic hindrances and high overpotentials, while at the same time no marketable value is created (atmospheric oxygen is free to use). In spite of exciting science created, application in real industrial set‐ups is currently impossible, and possible funding promises to contribute to a sustainable society become a debt difficult to return. We discuss possible alternative targets of (photo)electrochemistry as entry points where chemical value products and technical oxidants are created, with partially greater ease, lower losses, and higher benefits. [ABSTRACT FROM AUTHOR]

Abstract: A series of salt‐templated carbons with gradually changed pore structure and their corresponding nitrogen‐doped analogues are synthesized and applied as model systems to thoroughly study the ion migration dynamics and energy storage mechanism in hierarchical pore structures with different surface functionalization in electric double‐layer capacitors with a model ionic liquid electrolyte (1‐ethyl‐3‐methylimidazolium tetrafluoroborate). Ion conformation and phase variation during the charging/discharging process and their contribution to the energy storage mechanism are investigated. A significant contribution of structural changes in the bulk of the ionic liquid electrolyte strengthening charge storage in the electric double‐layer beyond the usual expectations is uncovered. Furthermore, a quantitative model of the structure–dynamics relationship is proposed, in which the optimal ratio of mesopores to micropores is determined to be 3:1 in pore volume. Below this ratio, the ion dynamics can be promoted by increasing mesopore content and/or doping with nitrogen, while those parameters show only minor influence when the ratio is surpassing 3:1. Nitrogen doping in this system improves the rate capability (due to the enhanced ion transport dynamics) rather than the amount of energy stored. [ABSTRACT FROM AUTHOR]

A facile route to synthesize hydrophilically or hydrophobically grafted graphitic carbon nitride (g-CN) is reported. For this purpose, functionalized olefinic molecules with a low polymerization tendency are utilized for grafting onto the surface to preserve the features of g-CN while improving its dispersibility. One-pot, visible light-induced grafting yields highly dispersible g-CNs either in aqueous or organic media. Moreover, functional groups such as amines can be introduced, which yields pH-dependent dispersibility in aqueous media. Compared with unfunctionalized g-CN, low sonication times are sufficient to redisperse g-CN. In addition, because of increased dispersion stability, higher amounts of functionalized g-CN can be dispersed (up to 10% in aqueous dispersion and 2% in organic dispersion) when compared to unfunctionalized g-CN. [ABSTRACT FROM AUTHOR]

The abundant carbohydrate fructose is converted into two biofuel molecules, namely 2,5-dimethylfuran (DMF) and ethyl levulinate (EL) in a simple cascade flow reactor. With an overall yield of 85% (38.5% of 2,5-dimethylfuran and 47% of ethyl levulinate), the main remainder is unconverted fructose. The two column flow reactor set-up enables the adjustment of temperatures and reaction times in such a way that the reactive intermediate hydroxymethylfurfural (5-HMF) is generated in optimal yields and converted into the stable DMF immediately. The process is so simple and fast (＜20 min) that economic and sustainable production of these fuels and platform chemicals can be envisioned. A remaining minor char formation is regarded to be the major problem which has to be addressed by catalyst development. [ABSTRACT FROM AUTHOR]

Photocatalytic Diels–Alder (D–A) reactions with electron rich olefins are realized by graphitic carbon nitride (g- C3N4) under visible-light irradiation and aerobic conditions. This heterogeneous photoredox reaction system is highly efficient, and the apparent quantum yield reaches a remarkable value of 47% for the model reaction. Dioxygen plays a critical role as electron mediator, which is distinct from the previous reports in the homogeneous RuII complex photoredox system. Moreover, the reaction intermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate. [ABSTRACT FROM AUTHOR]

Photocatalytic Diels-Alder (D-A) reactions with electron rich olefins are realized by graphitic carbon nitride (g-C3N4) under visible-light irradiation and aerobic conditions. This heterogeneous photoredox reaction system is highly efficient, and the apparent quantum yield reaches a remarkable value of 47 % for the model reaction. Dioxygen plays a critical role as electron mediator, which is distinct from the previous reports in the homogeneous RuII complex photoredox system. Moreover, the reaction intermediate vinylcyclobutane is captured and monitored during the reaction, serving as a direct evidence for the proposed reaction mechanism. The cycloaddition process is thereby determined to be the combination of direct [4+2] cycloaddition and [2+2] cycloaddition followed by photocatalytic rearrangement of the vinylcyclobutane intermediate. [ABSTRACT FROM AUTHOR]

CO2 capture is a pressing global environmental issue that drives scientists to develop creative strategies for tackling this challenge. The concept in this contribution is to produce site-specific nitrogen doping in microporous carbon fibers. Following this approach a carbon/carbon heterojunction is created by using a poly(ionic liquid) (PIL) as a 'soft' activation agent that deposits nitrogen species exclusively on the surface of commercial microporous carbon fibers. This type of carbon-based biphasic heterojunction amplifies the interaction between carbon fiber and CO2 molecule for unusually high CO2 uptake and resistive sensing. [ABSTRACT FROM AUTHOR]

CO2 capture is a pressing global environmental issue that drives scientists to develop creative strategies for tackling this challenge. The concept in this contribution is to produce site-specific nitrogen doping in microporous carbon fibers. Following this approach a carbon/carbon heterojunction is created by using a poly(ionic liquid) (PIL) as a 'soft' activation agent that deposits nitrogen species exclusively on the surface of commercial microporous carbon fibers. This type of carbon-based biphasic heterojunction amplifies the interaction between carbon fiber and CO2 molecule for unusually high CO2 uptake and resistive sensing. [ABSTRACT FROM AUTHOR]

To extend fossil oil supplies, sustainable feed stocks for the production of useful reagents and polymers should be harnessed. In this regard, chemicals derived from plants are excellent candidates. While the vast majority of plant sources used for polymer science only contain C x H y O z , alkaloids such as caffeine, nicotine, and theophylline possess nitrogen functionality that can provide new functions for bioderived polymers and their synthesis. In this context, the chemistry of theophylline, a natural product found in chocolate and tea, is exploited to create a cationic 'poly(theophylline)' in a straightforward fashion for the first time. This work demonstrates how this new polymer can be synthesized and used for the creation of narrowly disperse cationic microspheres. [ABSTRACT FROM AUTHOR]

The past decade has witnessed rapid progress in the synthesis of nanoporous organic networks or polymer frameworks for various potential applications. Generally speaking, functionalization of porous networks to add extra properties and enhance materials performance could be achieved either during the pore formation (thus a concurrent approach) or by post-synthetic modification (a sequential approach). Nanoporous organic networks which include ion pairs bound in a covalent manner are of special importance and possess extreme application profiles. Within these nanoporous ionic organic networks (NIONs), here with a pore size in the range from sub-1 nm to 100 nm, we observe a synergistic coupling of the electrostatic interaction of charges, the nanoconfinement within pores and the addressable functional units in soft matter resulting in a wide variety of functions and applications, above all catalysis, energy storage and conversion, as well as environment-related operations. This review aims to highlight the recent progress in this area, and seeks to raise original perspectives that will stimulate future advancements at both the fundamental and applied level. [ABSTRACT FROM AUTHOR]

Carbon nitride (g-CN) has attracted significant interest in the last years as a robust, low-cost alternative to metal-based materials in different fields due to its low price, environmentally benign character, simple synthesis and tunable properties. In particular, g-CN demonstrates promising activity in energy-related applications such as photo and heterogeneous catalysis, batteries and electrolysis. However, while g-CN is already well-established as a photocatalyst, its utilization in (opto)electronic devices is still at an early stage. This Focus Review concentrates on the utilization of g-CN in solar and photoelectrochemical cells, electrolyzers and light emitting diode alongside the recap of new synthetic approaches. This review is expected to provide useful insights into the design and fabrication of g-CN based photoelectronic devices as well as g-CN working principles, including the main challenges toward its integration in optoelectronic devices. [ABSTRACT FROM AUTHOR]

This review discusses different strategies for the upgrading of biomass into sustainable monomers and building blocks as scaffolds for the preparation of green polymers and materials. [ABSTRACT FROM AUTHOR]

Carbon nitrides with the increased surface areas (≈90 m2 g−1) were prepared by the heat-treatment of melamine-[Al(NO3)3]⋅9 H2O complexes. Here, [Al(NO3)3] ⋅9 H2O was successfully used as a 'green template' and a hydrogen-bonding partner of melamine, simultaneously providing a distinct porosity and defined particle morphology for the resulting carbon nitrides. The influence of the solvent and precursors ratio on the stoichiometry of the complexes, as well as the morphology, optical properties, and photocatalytic activity of resulting products for Rhodamine B degradation and sacrificial hydrogen evolution were investigated. We also studied the temperature-induced transformations of the starting complex to access the reaction mechanism. The developed synthesis procedure results in a significantly increased photocatalytic activity (up to 20-fold) compared with that of the ground reference material. [ABSTRACT FROM AUTHOR]

A facile and sustainable synthetic strategy based on the coordination of natural polyphenols with metal ions is developed for the textural engineering of mesocrystals and hierarchical carbon nanomaterials. The desired control of coordination between ellagic acid and zinc ions enables the macroscopic self-assembly behavior of crystalline nanoplatelets to be tailored into round and elongated "peanut"-like micron-sized mesostructured particles. Direct carbonization of these mesocrystals generates hierarchically porous carbon particles in good yields, possessing bimodal micro- and mesoporous architecture along with a well-preserved macroscopic structure. The pore system provides both small storage sites, demonstrated by high CO2 uptake, and transport channels also accessible by larger molecules. [ABSTRACT FROM AUTHOR]

Eine Kombination aus Ionothermalsynthese und Heißinjektionstechnik führte zu aus Lösungsmitteln erzeugten neuartigen Kohlenstoffnanostrukturen. Bei kontrollierter Zugabe von gewöhnlichen Lösungsmitteln zu heißer Zinkchloridschmelze entstanden sphärische, schichtartige oder verzweigt-nanofaserige Nanopartikel mit erstaunlich hoher Kohlenstoffeffizienz. Die Verwendung Heteroatom-haltiger Lösungsmittel hatte die Herstellung von Kohlen mit Dotierungsgraden von bis zu 14 Gew.-% Stickstoff und 13 Gew.-% Schwefel zur Folge. Hohe Oberflächen und große Porenvolumina der Lösungsmittelkohlen von >1666 m2 g−1 und 2.80 cm3 g−1 sowie CO2-Absorptionskapazitäten von 4.13 mmol g−1 bei 273 K und 1 bar konnten erhalten werden. Die neuartige Methode ließ sich nicht nur auf reine Kohlen anwenden, sondern wurde zudem auf die Herstellung von Nanokompositmaterialien aus Kohlenstoff und anorganischen Verbindungen ausgeweitet. ZnS@C, Ni@C und Co@C wurden erfolgreich mit der 'kinderleichten' Methode hergestellt. Das Ni@C-Nanokomposit eignet sich zur elektrokatalytischen Wasserspaltung, vergleichbar zu kommerziellen Edelmetallkatalysatoren. [ABSTRACT FROM AUTHOR]

A combination of ionothermal synthesis and hot-injection techniques leads to novel nanocarbons made from organic solvents. Controlled addition of commonly used organic solvents into a hot ZnCl2 melt gives rise to spherical, sheetlike, and branched nanofibrous carbon nanoparticles with surprisingly high carbon efficiency. When heteroatom-containing solvents were used, the doping levels reach up to 14 wt. % nitrogen and 13 wt. % sulfur. Materials with high surface areas and large pore volumes of solvent carbons as high as 1666 m2 g−1 and 2.80 cm3 g−1 in addition to CO2 adsorption capacities of 4.13 mmol g−1 at 273 K and 1 bar can be obtained. The new method works not only for pure carbon materials, but was also extended for the synthesis of carbon/inorganic nanocomposites. ZnS@C, Ni@C, and Co@C were successfully prepared with this straightforward procedure. The obtained Ni@C nanocomposites perform well in the electrocatalytic water oxidation, comparable with commercial noble-metal catalysts. [ABSTRACT FROM AUTHOR]

An efficient water splitting electrocatalyst is presented. Cheap and sustainable cellulose filter paper, infiltrated with nickel acetate as the nickel source, and phenanthroline as a ligand and nitrogen source are carbonized together. Nitrogen functionalities turn out to be crucial coordination sites for the supported Ni/NiO(OH) particles. This simple and scalable one step procedure leads to powders, but also to complete membranes made of ≈10 wt% Ni, supported on nitrogen functionalized carbon. The non-noble catalyst shows a low onset potential (330 mV vs reversible hydrogen electrode), high current density (e.g., j > 25 mA cm−­2 at η = 430 mV), excellent kinetics (Tafel slope of 44 mV dec−1), and a very favorable stability (<5% decay after 10 h electrolysis) in the oxygen evolution. The performance is similar or even better compared to state-of-the-art noble metal catalysts (e.g., IrO2, Ir/C, Ru/C, and Pt/C). Because of the simple, cheap, and scalable preparation procedure the catalyst is highly promising for practical low price/tech applications. Interestingly, the system is also active in the hydrogen evolution reaction, leading to a promising bifunctional catalyst. The benchmark characteristics are η10 = 390 mV for oxygen evolution and η10 = 190 mV for hydrogen evolution, that is, an overall efficiency of 68% at 10 mA current density. [ABSTRACT FROM AUTHOR]

A simple, versatile and cheap synthetic route is demonstrated for the preparation of Co3O4 decorated blood powder derived heteroatom doped porous carbon (BDHC). The inorganic hybrid performs well as an advanced bifunctional non-precious metal electrocatalyst. The hybridization of Co3O4 with the blood-derived carbon results in improved activities not only towards the oxygen reduction reaction (ORR), but also in the reverse oxygen evolution reaction (OER). An improved ORR activity and a tuned four electron transfer selectivity can be assigned to a synergistic catalytic effect due the intimate contact between Co3O­4 particles and the highly conductive heteroatom doped carbon support, mediated by cobalt-nitrogen or cobalt-phosphorous coordination sites. This heterojunction may facilitate the electron transfer by preventing an accumulation of electron density within the Co3O­4 particles. The straight-forward and cheap synthesis of the highly active and durable electrocatalyst make it a promising candidate for a next-generation bifunctional electrocatalyst for applications such as reversible fuel cells/electrolyzers or metal air batteries. [ABSTRACT FROM AUTHOR]

In recent years, the simple synthesis of artificial humic substances (A-HS) by alkaline hydrothermal processing of waste biomass was described. This A-HS was shown to support water and mineral binding, to change soil structure, to avoid fertilizer mineralization, and to support plant growth. Many of the observed macroscopic effects could, however, not be directly related to the minute amounts of A-HS which have been added, and an A-HS stimulated microbiome was found to be the key for understanding. In this review, we describe such anthropogenic soil in the language of the modern concept of living engineered materials and identify natural and artificial HS as the enabler to set up the interactive microbial system along the interfaces of the mineral grains. In that, old chemical concepts as surface activity, redox mediation, and pH buffering are the base of the system structure build-up and the complex self-adaptability of biological systems. The resulting chemical/biological hybrid system has the potential to address world problems as soil fertility, nutrition of a growing world population, and climate change. [ABSTRACT FROM AUTHOR]

MXenes, a rapidly growing family of 2D transition metal carbides, carbonitrides, and nitrides, are one of the most promising high‐rate electrode materials for energy storage. Despite the significant progress achieved, the MXene synthesis process is still burdensome, involving several procedures including preparation of MAX, etching of MAX to MXene, and delamination. Here, a one‐pot molten salt electrochemical etching (E) method is proposed to achieve Ti2C MXene directly from elemental substances (Ti, Al, and C), which greatly simplifies the preparation process. In this work, different carbon sources, such as carbon nanotubes (CNT) and reduced graphene oxide (rGO), are reacted with Ti and Al micro‐powders to prepare Ti2AlC MAX with 1D and 2D tuned morphology followed by in situ electrochemical etching from Ti2AlC MAX to Ti2CTx MXene in low‐cost LiCl‐KCl. The introduction of the O surface group via further ammonium persulfate (APS) treatment can act in concert with Cl termination to activate the pseudocapacitive redox reaction of Ti2CClyOz in the non‐aqueous electrolyte, resulting in a Li+ storage capacity of up to 857 C g−1 (240 mAh g−1) with a high rate (86 mAh g−1 at 120 C) capability, which makes it promising for use as an anode material for fast‐charging batteries or hybrid devices in a non‐aqueous energy storage application. [ABSTRACT FROM AUTHOR]

The unique properties of 2D MXenes, such as metal‐like electrical conductivity and versatile surface chemistry, make them appealing for various applications, including energy storage. While surface terminations of 2D MXene are expected to have a key influence on their electrochemical properties, the conventional HF‐etching method limits the surface functional groups to F, OH, and O. In this study, O‐free, Cl‐terminated MXenes (noted as Ti3C2Clx) are first synthesized by a molten salt (FeCl2) etching route. Then, a substitution of surface termination from Cl to N is performed via post‐thermal treatment of Ti3C2Clx in Li3N containing molten salt electrolytes. While the Cl‐terminated pristine material does not show electrochemical activity, the surface‐modified, N‐containing Ti3C2Tx exhibits a unique capacitive‐like electrochemical signature in sulfuric acid aqueous electrolyte with rate performance—more than 300 F g−1 (84 mAh g−1) at 2 V s−1. These results show that control of the MXene surface chemistry enables the preparation of high‐performance electrodes in a previously not accessed limit of energy storage. [ABSTRACT FROM AUTHOR]

Direct ink writing is especially relevant to the biomedical field due to the customizable extrusion and the possibility of creating pre‐designed architectures. Abundant natural polymers are sustainable and biocompatible alternatives to synthetic and persistent polymers. The printing of pure nanocellulose suspensions proves difficult due to low solid loadings, high shrinkage, as well as non‐fitting rheology. Emulsion gels (emulgel) alternatives gain attention in the field owing to their favorable viscoelastic properties and the possibility of creating multiphase systems. The authors’ sulfur‐free cationic cellulose nanocrystals (CNC) of low degree of substitution enable straightforward deployment in Pickering emulsions. An emulgel ink co‐stabilized by cationic CNC and α‐cyclodextrin is introduced as an interfacial inclusion complex. All ink components are natural and biodegradable compounds. The produced emulgel inks allow for high fidelity printing and minimum shrinkage upon drying that relaxes the need for supports, even in complex overhanging structures. A low yield stress (230–270 Pa) facilitates the inclusion of cells for biomedical applications into the formulation. The emulgel can be tuned to the desired rheological properties and be equipped with both polar and apolar compounds due to the biphasic system, making it a promising platform for biocompatible additive manufacturing. [ABSTRACT FROM AUTHOR]

Copper (Cu)‐based catalysts have established their unique capability for yielding wide value‐added products from CO2. Herein, we demonstrate that the pathways of the electrocatalytic CO2 reduction reaction (CO2RR) can be rationally altered toward C1 or C2+ products by simply optimizing the coordination of Cu with O‐containing organic species (squaric acid (H2C4O4) and cyclohexanehexaone (C6O6)). It is revealed that the strength of Cu−O bonds can significantly affect the morphologies and electronic structures of derived Cu catalysts, resulting in the distinct behaviors during CO2RR. Specifically, the C6O6−Cu catalysts made up from organized nanodomains shows a dominant C1 pathway with a total Faradaic efficiency (FE) of 63.7 % at −0.6 V (versus reversible hydrogen electrode, RHE). In comparison, the C4O4−Cu with an about perfect crystalline structure results in uniformly dispersed Cu‐atoms, showing a notable FE of 65.8 % for C2+ products with enhanced capability of C−C coupling. The latter system also shows stable operation over at least 10 h with a high current density of 205.1 mA cm−2 at −1.0 VRHE, i.e. is already at the boarder of practical relevance. This study sheds light on the rational design of Cu‐based catalysts for directing the CO2RR reaction pathway. [ABSTRACT FROM AUTHOR]

Copper (Cu)‐based catalysts have established their unique capability for yielding wide value‐added products from CO2. Herein, we demonstrate that the pathways of the electrocatalytic CO2 reduction reaction (CO2RR) can be rationally altered toward C1 or C2+ products by simply optimizing the coordination of Cu with O‐containing organic species (squaric acid (H2C4O4) and cyclohexanehexaone (C6O6)). It is revealed that the strength of Cu−O bonds can significantly affect the morphologies and electronic structures of derived Cu catalysts, resulting in the distinct behaviors during CO2RR. Specifically, the C6O6−Cu catalysts made up from organized nanodomains shows a dominant C1 pathway with a total Faradaic efficiency (FE) of 63.7 % at −0.6 V (versus reversible hydrogen electrode, RHE). In comparison, the C4O4−Cu with an about perfect crystalline structure results in uniformly dispersed Cu‐atoms, showing a notable FE of 65.8 % for C2+ products with enhanced capability of C−C coupling. The latter system also shows stable operation over at least 10 h with a high current density of 205.1 mA cm−2 at −1.0 VRHE, i.e. is already at the boarder of practical relevance. This study sheds light on the rational design of Cu‐based catalysts for directing the CO2RR reaction pathway. [ABSTRACT FROM AUTHOR]

The metal-free, polymeric semiconductor graphitic carbon nitride (g-CN) family is an emerging class of materials and has striking advantages compared to other semiconductors, i.e. ease of tunability, low cost and synthesis from abundant precursors in a chemical environment. Efforts have been done to improve the properties of g-CN, such as photocatalytic efficiency, designing novel composites, processability and scalability towards discovering novel applications as a remedy for the problems that we are facing today. Despite the fact that the main efforts to improve g-CN come from a catalysis perspective, many fundamental possibilities arise from the special colloidal properties of carbon nitride particles, from synthesis to applications. This review will display how typical colloid chemistry tools can be employed to make 'better g-CNs' and how up to now overseen properties can be levered by integrating a colloid and interface perspective into materials chemistry. Establishing a knowledge on the origins of colloidal behavior of g-CN will be the core of the review. Unlabelled Image • Establishing a colloidal background for carbon nitride science is targeted. • Colloidal aspects of carbon nitride synthesis will be reviewed. • The role of colloid chemistry and interfaces for hybrid formation will be revealed. • Carbon nitride as Pickering stabilizer will be discussed. • Carbon nitride-polymer-colloid relation will be established. [ABSTRACT FROM AUTHOR]

Humic Acid is a natural polymer with high functionality which is omnipresent in Nature, but was up to now hardly considered as an object of polymer synthesis. We review the known structural properties of natural humic acids which are remarkably uniform, independent of source and origin and environment. We then present its simple retrosynthesis in the lab based on a hydrothermal polycondensation process. The for a polymer very unusual properties of Humic Acid, such as pH and redox buffering, strong ion binding, but also its ability to bind and carry both hydrophobic and very hydrophilic molecules make artificial humic acid also an exciting choice as a functional polymer for technical purposes. [ABSTRACT FROM AUTHOR]

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen‐containing molecules. Here, we report the sustainable production of amino acids from biomass‐derived hydroxy acids with high activity under visible‐light irradiation and mild conditions, using atomic ruthenium‐promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu−1 ⋅ h−1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O−H bond dissociation of the α‐hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH−OH and CH3−CH−OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine. [ABSTRACT FROM AUTHOR]

Amino acids are the building blocks of proteins and are widely used as important ingredients for other nitrogen‐containing molecules. Here, we report the sustainable production of amino acids from biomass‐derived hydroxy acids with high activity under visible‐light irradiation and mild conditions, using atomic ruthenium‐promoted cadmium sulfide (Ru1/CdS). On a metal basis, the optimized Ru1/CdS exhibits a maximal alanine formation rate of 26.0 molAla ⋅ gRu−1 ⋅ h−1, which is 1.7 times and more than two orders of magnitude higher than that of its nanoparticle counterpart and the conventional thermocatalytic process, respectively. Integrated spectroscopic analysis and density functional theory calculations attribute the high performance of Ru1/CdS to the facilitated charge separation and O−H bond dissociation of the α‐hydroxy group, here of lactic acid. The operando nuclear magnetic resonance further infers a unique "double activation" mechanism of both the CH−OH and CH3−CH−OH structures in lactic acid, which significantly accelerates its photocatalytic amination toward alanine. [ABSTRACT FROM AUTHOR]

Cross-coupling reactions play a vital role in modern organic synthesis, enabling the construction of necessary C–C or C–(het)atom bonds for synthetic transformations. Although C(sp2)–C and C(sp2)–N cross-coupling reactions have received significant attention, recent advancements have also highlighted the significance of C(sp2)–S cross-coupling reactions. These reactions lead to the synthesis of valuable compounds, including pharmaceuticals and materials. In a recent report, we introduced Adaptive Dynamic Homogeneous Catalysis (AD-HoC) as an efficient method for C(sp2)–S cross-coupling reactions. This method operates without the need for any ligands, base, or additional additives, relying solely on essential parameters. In this report, we discuss the use of mesoporous graphitic carbon nitride (mpg-CN) as an all-organic heterogeneous photocatalyst in such transformations. The versatility and robustness of the reaction are showcased with fifty synthetic examples, achieving up to a 98% yield. The use of mpg-CN as a catalyst additionally enables the easy recovery of the photocatalyst from the reaction mixture and facilitates the sequential execution of multiple cross-coupling reactions with consistent yields of the desired products using a simple setup. This approach is a significant advancement in the field, both in terms of operational simplicity and environmental impact, traits that we all envision for sustainability. [ABSTRACT FROM AUTHOR]

According to the principles of chemical thermodynamics, the catalytic activation of small molecules (like N2 in air and CO2 in flue gas) generally exhibits a negative activity dependence on O2 owning to the competitive oxygen reduction reaction (ORR). Nevertheless, some catalysts can show positive activity dependence for N2 electrofixation, an important route to produce ammonia under ambient condition. Here we report that the positive activity dependence on O2 of (Ni0.20Co0.20Fe0.20Mn0.19Mo0.21)3S4 catalyst arises from high‐entropy mechanism. Through experimental and theoretical studies, we demonstrate that under the reaction condition in the mixed N2/O2, the adsorption of O2 on high‐entropy catalyst contributes to activating N2 molecules characteristic of elongated N≡N bond lengths. As comparison to the low‐ and medium‐entropy counterparts, high entropy can play the second role of attenuating competitive ORR by displaying a negative exponential entropy‐ORR activity relationship. Accordingly, benefiting from the O2, the system for direct air electrofixation has demonstrated an ammonia yield rate of 47.70 μg h−1 cm−2, which is even 1.5 times of pure N2 feedstock (31.92 μg h−1 cm−2), overtaking all previous reports for this reaction. We expect the present finding providing an additional dimension to high entropy that leverages systems beyond the constraint of traditional rules. [ABSTRACT FROM AUTHOR]

According to the principles of chemical thermodynamics, the catalytic activation of small molecules (like N2 in air and CO2 in flue gas) generally exhibits a negative activity dependence on O2 owning to the competitive oxygen reduction reaction (ORR). Nevertheless, some catalysts can show positive activity dependence for N2 electrofixation, an important route to produce ammonia under ambient condition. Here we report that the positive activity dependence on O2 of (Ni0.20Co0.20Fe0.20Mn0.19Mo0.21)3S4 catalyst arises from high‐entropy mechanism. Through experimental and theoretical studies, we demonstrate that under the reaction condition in the mixed N2/O2, the adsorption of O2 on high‐entropy catalyst contributes to activating N2 molecules characteristic of elongated N≡N bond lengths. As comparison to the low‐ and medium‐entropy counterparts, high entropy can play the second role of attenuating competitive ORR by displaying a negative exponential entropy‐ORR activity relationship. Accordingly, benefiting from the O2, the system for direct air electrofixation has demonstrated an ammonia yield rate of 47.70 μg h−1 cm−2, which is even 1.5 times of pure N2 feedstock (31.92 μg h−1 cm−2), overtaking all previous reports for this reaction. We expect the present finding providing an additional dimension to high entropy that leverages systems beyond the constraint of traditional rules. [ABSTRACT FROM AUTHOR]