Metal–Organic Frameworks-Derived Core/Shell Porous Carbon Materials Interconnected by Reduced Graphene Oxide as Effective Cathode Catalysts for Microbial Fuel Cells

Abstract

Microbial fuel cells (MFCs) are highly appealing for recovering electricity from organic matter, with the help of electrogenic bacteria. However, the lack of cost-efficient oxygen reduction reaction (ORR) catalysts is the main limitation for the performance of MFCs, and the development of highly electrocatalytic active ORR catalysts for MFCs remains very challenging. Here, core/shell carbon materials doped with Co and N (NC@CoNC) are prepared from bimetallic metal–organic frameworks (MOFs) via a facile pyrolysis method. After being interconnected by reduced graphene oxide (rGO), this unique NC@CoNC/rGO composite exhibits excellent electrocatalytic activity when used as the cathode catalyst in MFCs. The as-fabricated NC@CoNC/rGO catalyst facilitates favorable four-electron ORR, which can be due to the uniform distribution of Co nanoparticles, high N content, large surface area, and conductive graphene framework. Furthermore, the optimized NC@CoNC/rGO achieves a maximum power density of 2350 mW m–2, which is even higher than that generated with commercial Pt/C (2002 mW m–2). This work demonstrates that the nonprecious metal catalyst NC@CoNC/rGO can be considered to be an good alternative in MFCs.

Co-N-Doped Directional Multichannel PAN/CA-Based Electrospun Carbon Nanofibers as High-Efficiency Bifunctional Oxygen Electrocatalysts for Zn–Air Batteries

“…The sp 3 hybridization ratio in Co-N@PCNFs-0.2 (28.22 at%) is significantly more than that in Co-N/C (20.13 at%), indicating that Co-N@PCNFs-0.2 has more defective carbons (Figure a). The defective carbon structure is thought to produce more electrocatalytic active sites . The high-resolution N 1s spectra show four different types of peaks, which are graphitized N (401.6 eV), pyrrolic N (400.8 eV), Co-N (399.2 eV), and pyridinic N (398.4 eV), respectively (Figure b).…”

“…The defective carbon structure is thought to produce more electrocatalytic active sites. 46 The high-resolution N 1s spectra show four different types of peaks, which are graphitized N (401.6 eV), pyrrolic N (400.8 eV), Co-N (399.2 eV), and pyridinic N (398.4 eV), respectively (Figure 4b). Among them, the Co-N component in Co-N@PCNFs-0.2 (23.14 at%) is more than that in Co-N/C (17.17 at%), which will optimize the bond strength between the Co center and ORR intermediates and result in the subsequent reduction of O 2 via a four-electron-dominated process.…”

Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

“…Nanohybrids of Zn/Co bimetallic metal–organic frameworks (MOFs) on GO (MOF@GO) with a sandwich structure were prepared by a simple in-situ growth method [ 190 , 191 , 192 , 193 , 194 , 195 ]. To achieve the homogeneous growth of MOFs on the GO layers, a new approach of adjusting the ratio of Zn and Co sources was proposed to effectively control the size and distribution of the grown MOFs ( Figure 27 ) [ 195 ].…”

Core–Shell MOFs@MOFs: Diverse Designability and Enhanced Selectivity

“…Extensive efforts have been made in the construction of MOFs-based catalysts; , in particular, MOFs@MOFs with diverse structures and tunable properties have shown great potential in the field of catalysis, and various MOFs@MOFs composites and their derivatives have been applied in organocatalysis, − photocatalysis, ,, and electrocatalysis − with enhanced catalytic performance compared with individual MOF systems due to the synergistic effect and emerging properties after the integration of MOFs. Here, we focus on the enhanced selectivity of MOFs@MOFs-based catalysts; the emergence of MOFs@MOFs has provided a new and promising platform for selective catalysis due to the flexible integration of various MOFs with ideal and controllable properties.…”