The electrocatalytic nitrogen reduction reaction (NRR) on metal-free catalysts is an attractive alternative to the industrial Haber-Bosch process. However, the state-of-the-art metal-free electrocatalysts still suffer from low Faraday efficiencies and low ammonia yields. Herein, we present a molecular design strategy to develop a defective boron carbon nitride (BCN) catalyst with the abundant unsaturated B and N atoms as Lewis acid and base sites, which upgrades the catalyst from a single "Lewis acid catalysis" to "frustrated Lewis pairs (FLPs) catalysis." N / N exchange experiments and density functional theory (DFT) calculations reveal that FLPs can adsorb an N molecule to form a six-membered ring intermediate, which enables the cleavage of N via a pull-pull effect, thereby significantly reducing the energy barrier to -0.28 eV. Impressively, BCN achieves a high Faraday efficiency of 18.9 %, an ammonia yield of 20.9 μg h mg , and long-term durability.
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http://dx.doi.org/10.1002/anie.202207807 | DOI Listing |
J Am Chem Soc
January 2025
College of Chemical Engineering, Xiangtan University, Xiangtan 411105, China.
The development of all-solid-state frustrated Lewis pairs (FLPs) metal-free hydrogenation catalysts with excellent activity and stability remains a significant challenge. In this work, B, N codoped FLPs catalysts (De-rGO-NB) were prepared by the strategy of fabricating carbon defects and heteroatom doping on the surface of reduced graphene oxide and applied in the selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols. It was found that electron-rich pyridine-N (Lewis base) and adjacent electron-deficient B-N (Lewis acid) sites could be constructed on the surface of reduced graphene oxide using dicyandiamide and metaboric acid as N and B sources, thus forming FLPs sites.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
Controlling materials' composition and structure to selectively adsorb rare earth elements (REE) is critical for better separations. Understanding how local electric potentials affect REE adsorption and how they can be modified via chemical substitution is of fundamental importance. We present calculated mean inner potentials for muscovite and phlogopite micas in excellent agreement with measured values of +10.
View Article and Find Full Text PDFAm J Clin Nutr
January 2025
Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA. Electronic address:
Background: While healthy dietary and lifestyle factors have been individually linked to lower colorectal cancer (CRC) risks, recommendations for whole diet-lifestyle patterns remained unestablished due to limited studies and inconsistent pattern definitions.
Objective: This updated review synthesized literature on dietary-lifestyle patterns and CRC risk/mortality.
Methods: PubMed and Embase were searched through 31 March 2023 for randomized controlled trials and prospective cohort studies examining adulthood dietary patterns combined with modifiable lifestyle factors such as adiposity, smoking, alcohol consumption, physical activity, and/or others.
Angew Chem Int Ed Engl
January 2025
Department of Chemistry, University of North Texas CHEM 305D. 1508 W Mulberry St, Denton, Texas, 76201, United States.
Converting CO to high-value fine chemicals represents one of the most promising approaches to combat global warming and subsequently achieve a sustainable carbon cycle. Herein, we contribute an organoboron functionalized ultra-thin metal-organic nanosheet (MON), termed TCPB-Zr-NS, featuring an abundance of exposed Lewis acidic B and formate sites, which can effectively promote CO conversion upon the addition of Lewis basic o-phenylenediamines. Compared with the prototypical 3D analogue TCPB-Zr-3D, the resultant TCPB-Zr-NS showcases dramatically improved catalytic activity for the cyclization of o-phenylenediamine as a result of the highly exposed active sites and efficient substrates/products diffusion.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
The bifunctional mechanism, involving multiactive compositions to simultaneously dissociate water molecules and optimize intermediate adsorption, has been widely used in the design of catalysts to boost water electrolysis for sustainable hydrogen energy production but remains debatable due to difficulties in accurately identifying the reaction process. Here, we proposed the concept of well-defined Lewis pairs in single-atom catalysts, with a unique acid-base nature, to comprehensively understand the exact role of multiactive compositions in an alkaline hydrogen evolution reaction. By facilely adjusting active moieties, the induced synergistic effect between Lewis pairs (M-P/S/Cr pairs, M = Ru, Ir, Pt) can significantly facilitate the cleavage of the H-OH bond and accelerate the removal of intermediates, thereby switching the rate-determining step from the Volmer step to the Heyrovsky step.
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