Effect of Mo2C-functionalized electrode interface on enhancing microbial cathode electrocatalysis: Beyond electrochemical hydrogen evolution. (1st March 2023)

• Record Type: Journal Article
• Authors: Zhu, Qi; Peng, Jiaxin; Huang, Yunhong; Ni, Haiyan; Long, Zhong-er; Zou, Long
• Is Part Of: Electrochimica acta. Volume 443(2023)
• Publication Date: 2023-03-01
• Subjects: Microbial electrocatalysis -- Extracellular electron transfer -- Molybdenum carbide -- Electrode interface -- Shewanella; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2023.141924
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: Mo2 C-functionalized interface enhances microbial cathode electrocatalysis. Electric reduction of fumarate by shewanella has thermodynamic precedence over HER. The current consumption density of Mo2 C-modified cathode is increased by 3 times. The mechanism of Mo2 C accelerating microbial cathode reaction is elucidated. Abstract: Mo2 C has recently been introduced into microbial cathode electrocatalysis due to its well-known catalytic activity for hydrogen evolution reaction (HER), but a low electrode potential (i.e., a high energy input) is required usually. However, in the range of potential where HER cannot occur, its effect on microorganism/cathode interfacial kinetics remains unknown. Herein, an active Mo2 C interface is constructed on conventional carbon cloth electrode to investigate its impact on electric-driven fumarate reduction by a typical electroactive microorganism ( Shewanella oneidensis MR-1) at a potential of −0.36 V (vs . standard hydrogen electrode) that cannot meet the HER requirement. The Mo2 C-functionalized electrode achieves a greatly increased current consumption density of ∼0.041 mA cm −2, about three times that of the control, indicating a faster fumarate reduction rate. This substantially proves that the enhancement of microbial electrocatalytic kinetics at Mo2 C-functionalized interface is not confined to the induced hydrogen evolution. By analyzing its interaction with extracellular electron transfer mediators (e.g., c -type cytochromes and riboflavin), a robust inward extracellular electron transfer process based on the rapid electrochemical reaction of riboflavin at the Mo2 C-functionalized interface is elaborated. This work provides a new understanding of the mechanism by which the nanostructured Mo2 C interface enhances microbial cathode electrocatalysis.