Metal‐Free Carbonaceous Materials as Promising Heterogeneous Catalysts

Abstract

Metal‐free carbonaceous materials have attracted considerable interests as heterogeneous catalysts owing to their superior physiochemical properties over metal‐based catalysts, such as low cost, no pollution, chemical and thermal stabilities, as well as readily tailorable porous structure and surface chemistry. This review article provides an overview of the fundamentals and recent advances in the field of metal‐free carbon catalysts, including graphenes, carbon nanotubes, mesoporous carbons, graphitic carbon nitrides, and related composites. Special focus is placed on their controllable preparation and applications in gas phase, liquid phase, electrochemical, and photocatalytic reactions, as well as defect and surface chemistry related catalytic activities of carbon materials. Some perspectives are highlighted on the development of more efficient metal‐free carbonaceous catalysts featuring high stability, low cost, optimized structures, and enhanced performance, which are the key factors to accelerate the designed preparation and commercialization of carbocatalysts.

ZnO Nanoclusters Supported on Dealuminated Zeolite β as a Novel Catalyst for Direct Dehydrogenation of Propane to Propylene

“…[28,36] The 29 Si MAS NMR spectra of the selected samples are shown in Figure 2b. The spectrum of raw Hβ zeolite shows the peaks centered at À 103, À 106 and À 110 ppm, corresponding to the framework Si(OSi) 3 (OH), Si (OSi) 3 (OAl) and Si(OSi) 4 , respectively. [42] Upon the dealumination, the peak at À 103 ppm has no obvious change while the peak at À 106 ppm almost disappears, further evidencing the removal of Al atoms from the framework.…”

“…Propylene is a vital building block in petrochemical industry, which can synthesize numerous high-valued chemical products such as polypropylene, acrylic acid, acrylonitrile and so on. [1,2,3,4] The traditional ways of producing propylene, including steam cracking and fluid catalytic cracking (FCC), cannot produce enough propylene to meet with the market demand ascribed to the depletion of petroleum. Due to the rich source of propane and the great price gap between propane and propylene, direct dehydrogenation of propane to propylene (PDH) has been regarded as one of the most effective ways.…”

Graphene Quantum‐Dot‐Modified Hexagonal Tubular Carbon Nitride for Visible‐Light Photocatalytic Hydrogen Evolution

“…Allo ft he samples exhibited multiple broad peaks in the 3000-3600 cm À1 region assigned to residual NÀHg roups and OÀHb ands, which originatedf rom uncondensed amino groups ands urface-adsorbed H 2 Om olecules. 15 (Figure 2b), which is contributed to blue photoluminescence emitted by GQDs anchored on its surface. [29] The morphologies and microstructures of BCN, P-TCN, the GQD solution and P-TCN/GQDs-0.…”

Layer Stacked Iodine and Phosphorus Co‐doped C3N4 for Enhanced Visible‐Light Photocatalytic Hydrogen Evolution

“…Figure (a) shows the X‐ray diffraction (XRD) patterns of I/P‐CN‐1 to I/P‐CN‐4 and bulk C 3 N 4 (CN). Two characteristic peaks of graphite‐like carbon nitride are observed in all five samples, a small peak at 13.1° corresponding to (1 0 0) and a strong peak around 27.2° corresponding to (0 0 2) of g‐C 3 N 4 . To observe the structural changes in detail of carbon nitride after the element doping process, the enlargement image of (0 0 2) peak (inset of Figure (a)) shows that the peak position decreases from 27.28° to 27.17° compared with undoped CN, signifying an increase in the interlayer spaces of carbon nitride.…”