Recent Advancements in the Synthesis and Application of Carbon-Based Catalysts in the ORR

Abstract

Fuel cells are a promising alternative to non-renewable energy production industries such as petroleum and natural gas. The cathodic oxygen reduction reaction (ORR), which makes fuel cell technology possible, is sluggish under normal conditions. Thus, catalysts must be used to allow fuel cells to operate efficiently. Traditionally, platinum (Pt) catalysts are often utilized as they exhibit a highly efficient ORR with low overpotential values. However, Pt is an expensive and precious metal, posing economic problems for commercialization. Herein, advances in carbon-based catalysts are reviewed for their application in ORRs due to their abundance and low-cost syntheses. Various synthetic methods from different renewable sources are presented, and their catalytic properties are compared. Likewise, the effects of heteroatom and non-precious metal doping, surface area, and porosity on their performance are investigated. Carbon-based support materials are discussed in relation to their physical properties and the subsequent effect on Pt ORR performance. Lastly, advances in fuel cell electrolytes for various fuel cell types are presented. This review aims to provide valuable insight into current challenges in fuel cell performance and how they can be overcome using carbon-based materials and next generation electrolytes.

Organic aerogel as electro‐catalytic support in low‐temperature fuel cell

“…21 The texture and pore size resulting in the synthesis method plays a significant role in providing robust catalytic support for fuel cell applications. 22 Alegre et al 18 demonstrated that it is possible to minimize the rate of mass transfer at the catalyst layer based on the special pore texture of the modifiable carbon. The potential uses of organic aerogels have led to studies linked to their synthesis and use in the commercial and scientific.…”

“…Interestingly, almost all of the outcomes of research revealed that organic aerogels used as catalyst supports in low‐temperature fuel cell applications stabilize nano‐sized metal particles, resulting in a strong catalytic action 21 . The texture and pore size resulting in the synthesis method plays a significant role in providing robust catalytic support for fuel cell applications 22 . Alegre et al 18 demonstrated that it is possible to minimize the rate of mass transfer at the catalyst layer based on the special pore texture of the modifiable carbon.…”

The Effect of an External Magnetic Field on the Electrocatalytic Activity of Heat-Treated Cyanometallate Complexes towards the Oxygen Reduction Reaction in an Alkaline Medium

“…The synthesized catalytic material exhibited a broad diffraction peak at 2θ = 24.7 • , which corresponded to the (111) reflection plane, which is characteristic of the rGO_COOH carbon support [45]. After pyrolysis, the diffraction patterns of the catalyst (NFeC@rGO-COOH) appeared at angles of 17 210), (301), and (131) reflections, respectively, confirming the partial decomposition of PB during calcination, as well as the presence of additional coexisting phases Fe x C with the PB [46]. The obtained diffraction peaks are narrow, indicating the system's crystalline structure and the considerably large sizes of PB.…”

“…Sadly, the scarce resources, high prices, and decreased activity of Pt in the presence of small organic compounds (crossover effect in applications towards alcohol fuel cells) make them difficult to use in commercial applications. As a consequence, it is still challenging to develop efficient non-precious metal or metal-free catalysts for ORR [10][11][12][13][14][15][16][17][18].…”

Rationalizing Structural Hierarchy in the Design of Fuel Cell Electrode and Electrolyte Materials Derived from Metal-Organic Frameworks

“…The past few years have witnessed H 2 /O 2 fuel cells gaining increasing popularity as a result of their high efficiency and environmental friendliness. However, a potential problem is associated with the slow kinetics of the ORR [73,74] that can be a hindrance for practical applications. In order to commercialize ORR technologies in the future, it is vital to develop efficient catalysts.…”