Metal-Free Ketjenblack Incorporated Nitrogen-Doped Carbon Sheets Derived from Gelatin as Oxygen Reduction Catalysts

Abstract

Electrocatalysts facilitating oxygen reduction reaction (ORR) are vital components in advanced fuel cells and metal-air batteries. Here we report Ketjenblack incorporated nitrogen-doped carbon sheets derived from gelatin and apply these easily scalable materials as metal-free electrocatalysts for ORR. These carbon nanosheets demonstrate highly comparable catalytic activity for ORR as well as better durability than commercial Vulcan carbon supported Pt catalysts in alkaline media. Physico-chemical characterization and theoretical calculations suggest that proper combination of graphitic and pyridinic nitrogen species with more exposed edge sites effectively facilitates a formation of superoxide, [O2(ad)](-), via one-electron transfer, thus increasing catalytic activities for ORR. Our results demonstrate a novel strategy to expose more nitrogen doped edge sites by irregular stacked small sheets in developing better electrocatalysts for Zn-air batteries. These desirable architectures are embodied by an amphiphlilic gelatin mediated compatible synthetic strategy between hydrophobic carbon and aqueous water.

An Advanced Nitrogen‐Doped Graphene/Cobalt‐Embedded Porous Carbon Polyhedron Hybrid for Efficient Catalysis of Oxygen Reduction and Water Splitting

“…Assuming that the electrical conductivity of N/Co-doped PCP with RGO or NRGO is comparable (due to the small amount of N-doping), the difference was caused by the increase of structure defects in the hybrid originating from the N-doping of RGO sheets. Those defects (such as CN x structures) can serve as additional active sites to contribute to the improvement of catalytic activity, [ 34 ] which is in accordance with theoretical studies that the substitution of carbon by N atoms could result in the formation of disordered carbon nanostructures, and incorporation of N-donated electrons to carbon, [ 35 ] thus facilitating the ORR. Notably, there is increasing evidence suggesting that N doping into carbon is critical to enhancing catalytic activity for the ORR, HER, and OER.…”

Hydrothermal Synthesis of Boron and Nitrogen Codoped Hollow Graphene Microspheres with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

“…[19][20][21][22][23] The experimental observations and quantum mechanics calculations have attributed the high electrocatalytic activity of nitrogen doped carbon to the electron accepting ability of the nitrogen atoms, which created a net negative charge on the adjacent carbon atoms, facilitating the adsorption of oxygen and attraction of electrons from the anode for the reduction of oxygen. [24][25][26] Recent work has also address the use of boron doped carbon as the electrocatalyst for the ORR. [27][28][29] The larger difference between the electronegativity of oxygen and boron atoms makes 4 the adsorption of oxygen on boron dopants much easier.…”

Dual-site polydopamine spheres/CoFe layered double hydroxides for electrocatalytic oxygen reduction reaction

“…Although platinum-based material can meet the requirement of high ORR activity, the high cost and scarcity of platinum limit their practical applications [3]. Therefore, many non-precious catalysts have been designed, mainly including metal-free doped carbon materials with N [4,5], B [6], S [7] or F heteroatoms [8], M-N-C catalysts (M: Fe and/or Co) [9,10], and latest developments strongly coupled transition metal oxides/carbon (TMO/C) hybrids [11][12][13][14].…”