Spontaneously producing syngas from MFC-MEC coupling system based on biocompatible bifunctional metal-free electrocatalyst

Abstract

The preparation of high-value fuels and chemicals through the electrochemical carbon dioxide reduction reaction (CDRR) is of great significance to the virtuous cycle of carbon dioxide. However, due to the high overpotential involved in this reaction, high power consumption and highcost noble-metal-based catalysts are required for driving this process. Herein, the electrochemical CDRR was achieved on biocompatible metal-free nitrogen, phosphorus co-doped carbon-based materials (NP-C) in the microbial fuel cellmicrobial electrolysis cell (MFC-MEC) coupling system. As the bioelectrochemistry in MFC supplied power to drive the electrocatalysis in MEC, syngas was spontaneously produced from this coupling system without external energy input. With the NP-C materials as the excellent bifunctional electrocatalyst for the CDRR and oxygen reduction reaction (ORR), the current density of the MEC reached −0.52 mA cm −2 , and the Faradaic efficiencies (FEs) of CO and H 2 were 60% and 40%, respectively, at a load resistance of 10 Ω. Moreover, the CO/H 2 product ratio can be changed by adjusting the load resistance, which will widely meet various demand of syngas usage in further reactions. This study provides a spontaneous and tunable production of syngas in biogas digesters via a electrochemical strategy.

Renewable Power for Electrocatalytic Generation of Syngas: Tuning the Syngas Ratio by Manipulating the Active Sites and System Design

“…[165] The activity of carbon supports has also been altered through doping with non-metal elements, such as N and P. For example, Wang et al have developed a metal-free, N,P-doped carbon catalyst (by pyrolyzing microcrystalline cellulose, urea, and phytic acid) for use in a microbial fuel cell. [166] By adjusting the electrical resistance, the syngas ratio could be varied from 0.4 to 4.3, with N and P heteroatoms likely active for CO 2 RR and HER, respectively. N and P doping has similarly been employed to generate syngas in metal-free Se, B, N doped carbon catalysts.…”