The last few years have witnessed a wonderful technological renaissance that boosted the development of carbon-based nanomaterials (CNMs) doped with light heteroelements and featuring hierarchical porous architectures as valuable metal-free catalysts for a number of key industrial transformations. To date, several approaches to their synthesis have been developed, although many of them lack any real control of the final doping and composition. In contrast, chemical functionalization offers a unique and powerful tool to tailor CNMs' chemical and electronic surface properties as a function of their downstream application in catalysis. Different catalytic processes (hydrolysis/esterification/transesterification reactions, C-C bond forming reactions, CO2 derivatization into products of added value and electrochemical oxygen reduction reactions (ORR)) can be conveniently promoted by these materials. In addition, selected examples from this series offer a valuable platform for the in-depth comprehension of the underlying reaction mechanisms. This perspective article offers an overview on the main examples of ad hoc chemically decorated CNMs successfully exploited as metal-free catalysts, highlighting at the same time the importance of the surface chemistry control for the design of more active, metal-free and single-phase heterogeneous catalysts.
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http://dx.doi.org/10.2533/chimia.2017.568 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Graduate School of Environmental Science, Hokkaido University, N10, W5, Sapporo 060-0810, Japan.
We present a versatile approach to designing and utilizing high-performance nonmetal near-infrared (NIR) organic photocatalysts based on aromatic sulfones. Current NIR photocatalysts are mainly metal complexes and inorganic materials, while the few reported nonmetal organic NIR photocatalysts primarily use photosensitization to produce active species such as singlet oxygen. Our sulfone-rosamine-based redox photocatalyst demonstrates exceptional capabilities, including high ability for metal-free photo-oxidative bromination, intrinsically oxygen-independent redox reactions, and remarkable photostability with a turnover number (TON) exceeding 2800.
View Article and Find Full Text PDFChem Rev
January 2025
Department of Chemistry, Northeast Normal University, Changchun 130024, China.
-Sulfonyl hydrazones have been extensively used as operationally safe carbene precursors in modern organic synthesis due to their ready availability, facile functionalization, and environmental benignity. Over the past two decades, there has been tremendous progress in the carbene chemistry of -sulfonyl hydrazones in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Many carbene transfer reactions of -sulfonyl hydrazones are unique and cannot be achieved by any alternative methods.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, Faculty of Science, University of Kurdistan, Pasdaran Boulevard, Sanandaj 66177-15175, Iran.
Water splitting by an electrochemical method to generate hydrogen gas is an economic and green approach to resolve the looming energy and environmental crisis. Designing a composite electrocatalyst having integrated multichannel charge separation, robust stability, and low-cost facile scalability could be considered to address the issue of electrochemical hydrogen evolution. Herein, we report a superhydrophilic, noble-metal-free bimetallic nanostructure TiO/NiP coated on graphitic polyacrylonitrile carbon fibers (g-C/TiO/NiP) using a facile hydrothermal method followed by phosphorylation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Catalysis & Fine Chemicals, CSIR- Indian Institute of Chemical Technology, Uppal Road, Hyderabad, Telangana State 500007, India.
Photoassisted CO reduction employing a metal-free system is both challenging and fascinating. In our study, we present a structural engineering strategy to tune the potential energy barrier, which, in turn, affects the photoreduction ability. A series of porphyrin-based porous organic polymers () were hydrothermally synthesized and the influence of keto-enol tautomerization on the CO photoreduction potential has been rigorously investigated.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Science and Technology of China, National Synchrotron Radiation Laboratory, 42#, South Road of HeZuoHua, 230029, Hefei, CHINA.
Fe-N-C catalysts, with a planar D4h symmetric FeN4 structure, show promising as noble metal-free oxygen reduction reaction catalysts. Nonetheless, the highly symmetric structure restricts the effective manipulation of its geometric and electronic structures, impeding further enhancements in oxygen reduction reaction performance. Here, a high proportion of asymmetric edge-carbon was successfully introduced into Fe-N-C catalysts through morphology engineering, enabling the precise modulation of the FeN4 active site.
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