Multimodal chemo-/magneto-/phototaxis of 3G CNT-bots to power fuel cells

作     者：Shirsendu Mitra Nirmal Roy Surjendu Maity Dipankar Bandyopadhyay Shirsendu Mitra;Nirmal Roy;Surjendu Maity;Dipankar Bandyopadhyay

作者机构：Department of Chemical EngineeringIndian Institute of Technology GuwahatiGuwahatiAssam 781039India Centre for NanotechnologyIndian Institute of Technology GuwahatiGuwahatiAssam 781039India 

出 版 物：《Microsystems & Nanoengineering》 (微系统与纳米工程（英文）)

年 卷 期：2020年第6卷第1期

页      面：1149-1160页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080202[工学-机械电子工程] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0811[工学-控制科学与工程] 0702[理学-物理学] 

基　　金：We thank DST SERB,Grant no.EMR/2016/001824 MeitY-grant no.5(9)/2012-NANO the MHRD IMPRINT Project 8058,government of India,for financial support. 

主　　题：alkali dioxide gases 

摘      要：We report the development of a 3G microswimmer,namely,CNT-bot,capable of undergoing acid-,alkali-,magneto-and phototaxis inside acidic or alkaline baths of peroxide fuel and/or water.The use of carboxyl-functionalised multi-walled carbon nanotubes(MWCNTs)facilitated the propulsion of CNT-bots in an alkaline-water solution by ejecting carbon-dioxide bubbles.Furthermore,doping of magnetite nanoparticles(FeONPs),ferrous ions(Fe^(2+))and titanium dioxide nanoparticles(TiONPs)induces magnetic,chemical and photonic modes of propulsion.While FeONPs stimulated magnetotaxis at a rate of up to~10 body lengths per second under the influence of a bar magnet,chemotaxis of a similar speed in a peroxide fuel was achieved by bubble-propulsion of oxygen gas originating from the Fenton reaction.In addition,the light-stimulated photo-Fenton reaction led to phototaxis of CNT-bots.A thin coating of magnesium imparted a half-faced Janus appearance to the CNT-bots,which facilitated motion in normal or acidic water media through the ejection of hydrogen gas bubbles.This chemotaxis could be transformed into pH-stimulated directional motion by establishing an acid or alkali concentration gradient across the peroxide and/or water baths.The capacity of CNT-bots to produce oxygen(hydrogen)bubbles in peroxide(acidic water)fuel was exploited to power a PEM fuel cell to generate electricity.The pure oxygen and hydrogen gases generated by CNT-bots in separate chambers were fed directly into the fuel cell in which the incessant motions of the particle facilitated the creation and release of the pure gases to achieve on-demand electricity generation.The motor could also induce dye degradation through advanced oxidation owing to the production of intermediate hydroxyl radicals during the Fenton reaction.