Hierarchically Porous N-Doped Carbon Nanotubes/Reduced Graphene Oxide Composite for Promoting Flavin-Based Interfacial Electron Transfer in Microbial Fuel Cells

Abstract

Interfacial electron transfer between an electroactive biofilm and an electrode is a crucial step for microbial fuel cells (MFCs) and other bio-electrochemical systems. Here, a hierarchically porous nitrogen-doped carbon nanotubes (CNTs)/reduced graphene oxide (rGO) composite with polyaniline as the nitrogen source has been developed for the MFC anode. This composite possesses a nitrogen atom-doped surface for improved flavin redox reaction and a three-dimensional hierarchically porous structure for rich bacterial biofilm growth. The maximum power density achieved with the N-CNTs/rGO anode in S. putrefaciens CN32 MFCs is 1137 mW m, which is 8.9 times compared with that of the carbon cloth anode and also higher than those of N-CNTs (731.17 mW m), N-rGO (442.26 mW m), and the CNTs/rGO (779.9 mW m) composite without nitrogen doping. The greatly improved bio-electrocatalysis could be attributed to the enhanced adsorption of flavins on the N-doped surface and the high density of biofilm adhesion for fast interfacial electron transfer. This work reveals a synergistic effect from pore structure tailoring and surface chemistry designing to boost both the bio- and electrocatalysis in MFCs, which also provide insights for the bioelectrode design in other bio-electrochemical systems.

Cellulose Aerogel Derived Hierarchical Porous Carbon for Enhancing Flavin-Based Interfacial Electron Transfer in Microbial Fuel Cells

“…The XPS results (Figure 3c) show that the CPC-9 and CPC-12 possessed a little bit higher oxygen and nitrogen content than that of CPC-6, which reveals that increase of urea in precursor could promote the doping of nitrogen in the porous carbon. As the nitrogen doped carbon electrodes often exhibited superior performance in the MFC anode [27], the CPC-9 may achieve better bioelectrocatalysis performance than that of CPC-6 in MFCs. To evaluate the electrochemical behavior of flavins on the CPC electrodes, the cyclic voltammograms (CVs), differential pulse voltammograms (DPVs) and electrochemical impedance spectra (EIS) were measured in 0.1 M phosphate buffer with 2 μM FMN.…”

Ruthenium oxide/tungsten oxide composite nanofibers as anode catalysts for the green energy generation of Chlorella vulgaris mediated biophotovoltaic cells

“…The morphological features of 1D RuO 2 /WO 3 composite nanofibers afford abundant pores and cavities, which are beneficial for the large accessible active area for the efficient utilization and accommodation of microalgae, promoting the efficient diffusion of microalgae adhesion and growth . Furthermore, the continuous and interconnected nanofiber networks ensure the unobstructed channels for rapid and continuous electron transportation . The densely and uniformly decorated metal nanoparticles (RuO 2 /WO 3 ) create the considerable microporous structure on the surface of nanofibers that improves the light harvesting efficiency via penetrating the light energy into the bulk of the composite .…”

“…In general, the considerable electrons and hole pairs are formed at the surface of photocatalysts upon the light illumination. However, the photogenerated charge carriers endure recombination process under the nonexistence of electron transfer process . It is effectively tackled with RuO 2 /WO 3 nanofibers, in which the excited charge carriers display improved lifetime along with the elevated photoelectrochemical and catalytic processes with the aid of an efficient charge transfer phenomena, which substantiate the maximum BPV performance.…”

In Situ Silver-based Electrochemical Bioreactor In Vivo

“…Despite sharing similar structures with grapheme oxide (GO) ( Supplementary Fig. S4), rGO is preferred to promote electron separation and H 2 O 2 disproportionation due to its much higher catalytic activity [21][22][23] .…”

“…rGO is a well-accepted drug carrier [18][19][20] , which can accommodate Ag + -DNA. In addition, rGO features few oxygen-containing groups on its surface, and therefore bene ts rapid electron transfer [21][22][23] , which enables the rapid reduction of Ag + by H 2 O 2 in the tumor. Notably, DNA-Ag + conjugate prodrug is obtained via the coordination interaction, wherein DNA is highlighted to stabilize Ag + , manipulate Ag + loading content, avoid self-driven Ag+ nucleation and growth, improve biosafety via reducing Ag+ leakage and supply rich binding sites for the subsequent chitosan (CS) coating.…”