Chemical Approaches to Carbon‐Based Metal‐Free Catalysts

Abstract

Highly active and durable catalysts play a key role in clean energy technologies. However, the high cost, low reserves, and poor stability of noble‐metal‐based catalysts have hindered the large‐scale development of renewable energy. Owing to their low cost, earth abundance, high activity, and excellent stability, carbon‐based metal‐free catalysts (CMFCs) are promising alternatives to precious‐metal‐based catalysts. Although many synthetic methods based on solution, surface/interface, solid state, and noncovalent chemistries have been developed for producing numerous CMFCs with diverse structures and functionalities, there is still a lack of effective approaches to precisely control the structures of active sites. Therefore, novel chemical approaches are needed for the development of highly active and durable CMFCs that are capable of replacing precious‐metal catalysts for large‐scale applications. Herein, a comprehensive and critical review on chemical approaches to CMFCs is given by summarizing important advancements, current challenges, and future perspectives in this emerging field. Through such a critical review, our understanding of CMFCs and the associated synthetic processes will be significantly increased.

Carbon science perspective in 2020: Current research and future challenges

“…MOFs/COFs and some other ordered organic structures can be used as self-sacrificing templates/precursors to synthesize carbon catalysts, exhibiting advantages in terms of tailorable morphologies, hierarchical porosity and facile functionalization with other heteroatoms and metal/metal oxides [71]. A critical issue in carbon catalysis is the difficulty of precisely controlling their physical and chemical structures using standard organic/inorganic templates or precursors [72]. The key challenge during the carbonization of MOFs/ COFs lies in the careful control of their physical and chemical properties, which vary during pyrolysis or thermal annealing.…”

Metal-free carbocatalysis for electrochemical oxygen reduction reaction: Activity origin and mechanism

“…However, the durability issue, originated from the platinum degradation especially at a relatively high current density, acts as one of the primary limiting factors preventing large-scale commercialization of fuel cells. In the past decade, with the rapid development of metal-free carbon-based nanomaterials [4][5][6] , the effort s on ORR cat alyst s have been vit alized in terms of substituting platinum by carbon [7][8][9][10] . For fundamental researches, the ORR electrode kinetics on classical carbon materials has been well studied for decades, including graphite, glassy carbon, activated carbon, and so forth [11 , 12] .…”

Voltammetric Detection of Nitrite Anions Employing Imidazole Functionalized Reduced Graphene Oxide as an Electrocatalyst

“…Through electrode modifiers, metal free composites with electrocatalytic activity are very promising because of their high durability, lack of impurity poisoning, being environment friendly and commercialization capability [18]. These electrocatalysts are generally prepared by doping heteroatoms such as nitrogen, oxygen, phosphorus and sulfur into carbon nanostructures or physically and chemically functionalizing their surface with various functional groups and subsequently are widely used in energy conversion and storage devices and electrochemical sensors [19][20][21]. For instance Li et al introduced a novel N-doped graphene quantum dots decorated N-doped carbon nanofibers composite to determine nitrite ions present in sausage, pickle, lake water and tap water [22].…”