Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej A novel MXene-coated biocathode for enhanced microbial electrosynthesis performance Khurram Tahir a,b , Waheed Miran c , Jiseon Jang d , Asif Shahzad a , Mokrema Moztahida a , Bolam Kim a , Dae Sung Lee a, ⁎ a Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea b Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, 1.5 KM Defence Road, Off Raiwind Road, Lahore 54000, Pakistan c International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan d R&D Institute of Radioactive Wastes, Korea Radioactive Waste Agency, 174 Gajeong-ro, Yuseong-gu, Daejeon 34129, Republic of Korea HIGHLIGHTS • A novel MXene-coated CF cathode was fabricated using a facile dip-and-dry method. • The MXene@CF biocathode exhibited excellent microbial electrosynthesis performance. • A 2.9-fold increase in average current density was observed using the mod- ified cathode. • The MXene@CF biocathode produced a more continuous and electroactive biofilm. GRAPHICAL ABSTRACT ARTICLE INFO Keywords: Microbial electrosynthesis Ti 3 C 2 T X MXene Volatile fatty acids Cathode ABSTRACT Microbial electrosynthesis (MES) is a promising bioelectrochemical technology for the simultaneous consump- tion of carbon dioxide/bicarbonate and generation of useful chemical products. However, low current densities and a narrow product range with an inadequate production rate are bottlenecks in current MES technologies. In response to this, cathode modification has been suggested as a strategy to improve MES performance. Titanium carbide (Ti 3 C 2 T X MXene), a recently discovered 2D material, has a multilayered structure, high surface area, and excellent conductivity, which are prerequisites for an excellent cathode material. In this study, a novel MXene- coated carbon felt electrode (MXene@CF) was fabricated and investigated for use in MES. The modified cathode material exhibited excellent current generation and volatile fatty acid production. The availability of more active sites and sufficient space for microbial growth enhanced the mass transfer between the microbes and the sub- strate, resulting in a 1.6-, 1.1-, and 1.7-fold increase in the concentration of acetic, butyric, and propionic acid, respectively, compared to uncoated carbon felt. Scanning electron microscopy, electrochemical, and microbial community analyses revealed that the MXene-coated cathode promoted the formation and enrichment of bio- film. Thus, these results demonstrate that MXene@CF is a promising cathode material for MES. https://doi.org/10.1016/j.cej.2019.122687 Received 2 July 2019; Received in revised form 28 August 2019; Accepted 31 August 2019 ⁎ Corresponding author. E-mail address: daesung@knu.ac.kr (D.S. Lee). Chemical Engineering Journal 381 (2020) 122687 Available online 03 September 2019 1385-8947/ © 2019 Elsevier B.V. All rights reserved. T