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The electrocatalytic reduction of CO2 (ECO2RR) to syngas with tunable CO/H2 ratios offers a promising route for sustainable energy conversion and chemical production. Here, we report a series of N-doped carbon black (NCBx) catalysts with tailored nitrogen species that enable precise control over the composition of syngas. Among the catalysts, NCB3 exhibits the optimal performance, achieving high CO selectivity (64.14%) and activity (1.9 mA cm−2) in an H-type cell at −0.9 V. Furthermore, NCB3 produces syngas with a wide range of CO/H2 ratios (0.52 to 4.77) across the applied potentials (−0.5 to −1.0 V). Stability tests confirm the robust durability of NCB3, which maintains consistent activity and selectivity over prolonged electrolysis. This work demonstrates the critical role of nitrogen species in tuning ECO2RR pathways and establishes a strategy for designing efficient and stable carbon-based catalysts for CO2 utilization and syngas production.

The rise in diabetes and obesity worldwide has created an urgent demand for low-sugar, nutrient-dense foods with appealing flavors. This study established an endogenous and “rapid validation–stable production” platform to enhance the flavor of edible tomato fruits by integrating two key technologies in the MicroTom cherry tomato: (1) TRV viral vector-mediated transient expression and (2) Agrobacterium-mediated stable genetic transformation. We employed the human sweet taste receptor TAS1R2 for in vitro functional validation and objectively demonstrated that tomato-derived recombinant thaumatin II exhibits receptor-binding activity equivalent to that of the native protein, overcoming the limitations of traditional sensory evaluation. Non-targeted metabolomic analysis (covering 1236 metabolites) confirmed that thaumatin II expression did not significantly alter the profiles of sugars, organic acids, or key flavor compounds in tomato fruits. This provides safety data supporting the development of “ready-to-eat sugar-substitute fruits.” Our strategy offers a solution and theoretical technical support for the development of low-sugar, high-nutrient foods.

The electrocatalytic reduction of CO[sub.2] (ECO[sub.2]RR) to syngas with tunable CO/H[sub.2] ratios offers a promising route for sustainable energy conversion and chemical production. Here, we report a series of N-doped carbon black (NCBx) catalysts with tailored nitrogen species that enable precise control over the composition of syngas. Among the catalysts, NCB3 exhibits the optimal performance, achieving high CO selectivity (64.14%) and activity (1.9 mA cm[sup.−2]) in an H-type cell at −0.9 V. Furthermore, NCB3 produces syngas with a wide range of CO/H[sub.2] ratios (0.52 to 4.77) across the applied potentials (−0.5 to −1.0 V). Stability tests confirm the robust durability of NCB3, which maintains consistent activity and selectivity over prolonged electrolysis. This work demonstrates the critical role of nitrogen species in tuning ECO[sub.2]RR pathways and establishes a strategy for designing efficient and stable carbon-based catalysts for CO[sub.2] utilization and syngas production.

The electrocatalytic reduction of CO (ECO RR) to syngas with tunable CO/H ratios offers a promising route for sustainable energy conversion and chemical production. Here, we report a series of N-doped carbon black (NCBx) catalysts with tailored nitrogen species that enable precise control over the composition of syngas. Among the catalysts, NCB3 exhibits the optimal performance, achieving high CO selectivity (64.14%) and activity (1.9 mA cm ) in an H-type cell at -0.9 V. Furthermore, NCB3 produces syngas with a wide range of CO/H ratios (0.52 to 4.77) across the applied potentials (-0.5 to -1.0 V). Stability tests confirm the robust durability of NCB3, which maintains consistent activity and selectivity over prolonged electrolysis. This work demonstrates the critical role of nitrogen species in tuning ECO RR pathways and establishes a strategy for designing efficient and stable carbon-based catalysts for CO utilization and syngas production.

Carbon–carbon (C–C) bonds make up the skeletons of most organic molecules. The selective manipulation of C–C bonds offers a direct approach to editing molecular scaffolds but remains challenging. The kinetic inertness of C–C bonds can be overcome with transition-metal catalysis, which, nevertheless, relies on a substrate being highly strained or bearing a permanent directing group (DG). The driving force for C–C activation in these cases is strain relief and the formation of a stable metallocycle, respectively. Over the past two decades, a strategy has emerged that uses temporary or removable DGs to effect C–C activation of more common and less strained compounds. A variety of C–C bonds in less strained organic molecules are converted into more reactive transition-metal–carbon (M–C) bonds, enabling downstream transformations as part of diverse synthetic methods. This Review highlights catalytic approaches using temporary or removable DGs to help activate unstrained C–C bonds. The content is organized according to the temporary or removable nature of the DGs and includes applications in the synthesis of natural products or bioactive molecules. Selective manipulation of carbon–carbon bonds provides a direct approach to editing organic scaffolds. This Review describes the catalytic activation of unstrained carbon–carbon bonds enabled by temporary or removable directing groups.

Alkylation of carbonyl compounds is a commonly used carbon-carbon bond–forming reaction. However, the conventional enolate alkylation approach remains problematic due to lack of regioselectivity, risk of overalkylation, and the need for strongly basic conditions and expensive alkyl halide reagents. Here, we describe development of a ketone-alkylation strategy using simple olefins as the alkylating agents. This strategy employs a bifunctional catalyst comprising a secondary amine and a low-valent rhodium complex capable of activating ketones and olefins simultaneously. Both cyclic and acyclic ketones can be mono-α-alkylated with simple terminal olefins, such as ethylene, propylene, 1-hexene, and styrene, selectively at the less hindered site; a large number of functional groups are tolerated. The pH/redox neutral and byproduct-free nature of this dual-activation approach shows promise for large-scale syntheses.

HighlightsThe eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method.Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel.Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition..Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

HighlightsA flexible and lightweight microwave absorber was prepared by a vacuum filtration method.The remarkable microwave absorbency makes the absorber paper attractive in wireless wearable electronics field.Developing a flexible, lightweight and effective electromagnetic (EM) absorber remains challenging despite being on increasing demand as more wearable devices and portable electronics are commercialized. Herein, we report a flexible and lightweight hybrid paper by a facile vacuum-filtration-induced self-assembly process, in which cotton-derived carbon fibers serve as flexible skeletons, compactly surrounded by other microwave-attenuating components (reduced graphene oxide and Fe3O4@C nanowires). Owing to its unique architecture and synergy of the three components, the as-prepared hybrid paper exhibits flexible and lightweight features as well as superb microwave absorption performance. Maximum absorption intensity with reflection loss as low as − 63 dB can be achieved, and its broadest frequency absorption bandwidth of 5.8 GHz almost covers the entire Ku band. Such a hybrid paper is promising to cope with ever-increasing EM interference. The work also paves the way to develop low-cost and flexible EM wave absorber from biomass through a facile method.

While metathesis reactions involving carbon–carbon double bonds, namely olefin metathesis, have been well established with broad utility in organic synthesis and materials science, direct metathesis of kinetically less accessible C–C single bonds is extremely rare. Here we report a ruthenium-catalysed reversible C–C single-bond metathesis reaction that allows redox- and pH-neutral biaryl synthesis. Assisted by directing groups, unstrained homo-biaryl compounds undergo aryl exchanges to generate cross-biaryl products, catalysed by a well-defined air-stable ruthenium(II) complex. Functional groups reactive under typical cross-coupling reactions, such as halogen, silyl and boronate moieties, are compatible under the metathesis conditions. Mechanistic studies disclose an intriguing ‘olefin-metathesis-like’ pathway that involves an unexpected heptacoordinated, 18-electron closed-shell intermediate. The distinct reaction mode discovered here is expected to inspire the development of more general C–C single-bond metathesis and orthogonal cross-coupling reactions.Metathesis reactions involving carbon–carbon double bonds have been well established, but direct metathesis of carbon–carbon single bonds is extremely rare. Now, a ruthenium-catalysed carbon–carbon single-bond metathesis reaction has been developed with unstrained homo-biaryl substrates. The reaction shows wide functional group tolerance and operates via an ‘olefin-metathesis-like’ mechanism.

In the chemical industry, it is often necessary to activate carbon–carbon bonds in order to synthesize complex organic molecules, but this is challenging when starting with simple five- or six-membered carbon rings; a new method uses a rhodium pre-catalyst and an amino-pyridine co-catalyst, enabling an overall energetically favourable reaction that involves activation of carbon–carbon bonds plus activation of carbon–hydrogen bonds. Access to tetralones Most molecules of interest to organic chemists are primarily made up of carbon skeletons, so carbon–carbon bond activation is of prime importance in making and modifying such molecules. Transition-metal-mediated carbon–carbon bond activation of cyclic carbon species is a versatile approach, but challenging for five- and six-membered rings because the lack of ring strain provides an insufficient driving force for the reaction. Now, Guangbin Dong and co-workers demonstrate a rhodium-catalysed activation of phenyl-functionalized unstrained cyclopentanones, giving rapid access to tetralones. In the chemical industry, molecules of interest are based primarily on carbon skeletons. When synthesizing such molecules, the activation of carbon–carbon single bonds (C–C bonds) in simple substrates is strategically important: it offers a way of disconnecting such inert bonds, forming more active linkages (for example, between carbon and a transition metal) and eventually producing more versatile scaffolds 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 . The challenge in achieving such activation is the kinetic inertness of C–C bonds and the relative weakness of newly formed carbon–metal bonds 6 , 14 . The most common tactic starts with a three- or four-membered carbon-ring system 9 , 10 , 11 , 12 , 13 , in which strain release provides a crucial thermodynamic driving force. However, broadly useful methods that are based on catalytic activation of unstrained C–C bonds have proven elusive, because the cleavage process is much less energetically favourable. Here we report a general approach to the catalytic activation of C–C bonds in simple cyclopentanones and some cyclohexanones. The key to our success is the combination of a rhodium pre-catalyst, an N -heterocyclic carbene ligand and an amino-pyridine co-catalyst. When an aryl group is present in the C3 position of cyclopentanone, the less strained C–C bond can be activated; this is followed by activation of a carbon–hydrogen bond in the aryl group, leading to efficient synthesis of functionalized α-tetralones—a common structural motif and versatile building block in organic synthesis. Furthermore, this method can substantially enhance the efficiency of the enantioselective synthesis of some natural products of terpenoids. Density functional theory calculations reveal a mechanism involving an intriguing rhodium-bridged bicyclic intermediate.