Guiding Principles for Designing Highly Efficient Metal‐Free Carbon Catalysts

Abstract

Carbon nanomaterials are promising metal-free catalysts for energy conversion and storage, but the catalysts are usually developed via traditional trial-and-error methods. To rationally design and accelerate the search for the highly-efficient catalysts, it is necessary to establish design principles for the carbon-based catalysts. This review focuses on the theoretical analysis and material design of the metal-free carbon nanomaterials as efficient photo-/electro-catalysts to facilitate the critical chemical reactions in clean and sustainable energy technologies, including oxygen reduction reaction in fuel cells, oxygen evolution reaction in metal-air batteries, iodine reduction reaction in dye-sensitized solar cells, hydrogen evolution reaction in water splitting, and carbon dioxide reduction in artificial photosynthesis. Basic catalytic principles, computationally guided design approaches and intrinsic descriptors, catalytic material design strategies, and future directions are discussed for the rational design and synthesis of highly efficient carbon-based catalysts for clean energy technologies.

Detrimental Effects and Prevention of Acidic Electrolytes on Oxygen Reduction Reaction Catalytic Performance of Heteroatom-Doped Graphene Catalysts

“…(3) The acid anions can be segregated from the active sites as much as possible. For example, design multi-scale hierarchical porous structure 2019; Zhang L. et al, 2019), which could block the acid anions approaching to the reactive sites but not influence the transfer of reactants, products and reaction intermediates. (4) Defective graphene structure could be designed to make the active sites locate at the central part, not the edge of the graphene, because the acid anions prefer to aggregate at the edge of the graphene.…”

“…The doped heteroatoms (X = N, B, P) locating at the zigzag edges are favorable to boost the ORR catalytic activity (Jiang et al, 2007;Li et al, 2014;He et al, 2016). We mainly focus on nitrogen-doped graphene with pyridinic-N, which is considered to be the origin of catalytic activity (Li et al, 2014;Guo et al, 2016;Zhang L. et al, 2019). The GRs were constructed with periodic boundary condition in x-direction.…”

“…As mentioned above, the acid anion is one of the main factors that affect the catalytic activity of N-GR in acidic medium. The perchloric acid and sulfuric acid are the two most common acids used as acidic electrolytes in fuel cells (Mamtani et al, 2018;Sun et al, 2018;Mun et al, 2019;Zhang L. et al, 2019). In order to study the effects of acid anions on the catalytic activity of N-GR, we introduced acid anions (including ClO − 4 , SO 2− 4 , and HSO − 4 ) near the N-GR structures, and calculated the overpotential and reaction pathways.…”

“…Density functional theory (DFT) simulation is an effective theoretical approach to study the ORR mechanisms (Kulkarni et al, 2018;Wang et al, 2018b;Zhang L. et al, 2019). The direct interactions between the surface of catalysts and the intermediate radicals of ORR in vacuum have been broadly studied by the simulation methods Xue et al, 2018;Yang et al, 2018).…”

Atomic Modulation, Structural Design, and Systematic Optimization for Efficient Electrochemical Nitrogen Reduction

“…The development of electrochemical nitrogen reduction methods has been rather sluggish over the past several decades. However, significant progress in the fields of hydrogen/oxygen/carbon dioxide electrocatalysis, and advanced nanotechnologies have been made recently, serving as a solid foundation foreshadowing the nitrogen electroreduction field. Consequently, numerous electrocatalysts matching with a specific electrocatalytic system for nitrogen electroreduction have emerged in recent years.…”