Red Blood Cells-Derived Iron Self–Doped 3D Porous Carbon Networks for Efficient Oxygen Reduction

Zicong Zhang,Xiaoli Yang,Lin Yang,Xiangli Ru,Zhengyu Bai

doi:10.3390/catal12030273

Abstract

In addition to C, H and O, some biomass is also rich in mineral elements. The recovery and utilization of special mineral elements is of great significance to prepare functional materials and alleviate the current energy shortage. Herein, we describe a facile strategy for making full use of the chemical composition (C, Fe) and special structure of red blood cells (RBCs) from waste pig blood to fabricate a dual metal (Fe, Co)-nitrogen (N)-doped porous carbon catalyst by pyrolysis of a mixture of RBCs biomass, cobaltous acetate, and melamine. The porous catalyst displays a comparable activity for oxygen reduction reaction (ORR) to that of commercial Pt/C catalyst, with a half-wave potential of 0.821 VvsRHE in alkaline media and 0.672 VvsRHE in acid electrolyte. Especially, the as-prepared catalyst shows excellent methanol tolerance and stability in both acidic and alkaline electrolytes, which is superior to commercial Pt/C catalysts. The excellent ORR activity of FeCo-N/C(RBC) can be ascribed to the porous morphology and the cooperation between metal and nitrogen species. This work provides a novel idea of exploiting the composition of renewable biomass to modulate the activity and stability of carbon-based ORR catalysts.

Highlights

As the cathode catalytic reaction of metal–air batteries and fuel cells, oxygen reduction reaction (ORR) is an important process since it determines the efficiency of the relevant electrochemical energy conversion devices [9]
We find cobalt acetate and melamine play a critical role in the formation of the porous RBCshaped structure
The results demonstrate that the introduction of Co and N increases the concentration of catalyst defect sites, but reduces the degree of Catalysts 2022, 12, x FOR PEER REVIEW

Summary

Introduction

With the depletion of traditional energy and the environmental crisis, the demand for renewable and green energy is becoming more and more urgent [1–4]. The onset potential, half-wave potential and limiting current density of FeCo-N/C(RBC) is 0.958 VvsRHE, 0.831 VvsRHE and 5.547 mA cm−2 (Figure S4), respectively, and the half-wave potential is only 44 mV lower than that of 20 wt% Pt/C, indicating that FeCo-N/C(RBC) has excellent ORR activity This high ORR catalytic activity can be attributed to its unique porous structure constructed by the acetate volatilization and increased conductivity constructed by nitrogen doping, which causes a large specific surface area, exposing more active sites. The current density of commercial Pt/C goes down instantaneously, only 36.76% current density could be retained after the signal is steady These results demonstrate that FeCo-N/C(RBC) is the best ORR catalyst among the four as-prepared catalysts, which is contributed to by its more accessible catalytic active sites and the cooperation between metal and nitrogen species. The fixed RBCs were dried at 60 ◦C for 24 h

Preparation of Catalysts

Physical Characterization

Electrochemical Measurements

Findings

Conclusions