Classical chemical production using exothermic reactions is often faced with challenges of energy efficiency and selectivity. Electrochemical production using a fuel cell based reactor could provide a solution for energy saving (by cogeneration of electricity) and for selectivity (by using the optimal electrocatalyst). A novel fuel cell design, the co-laminar flow cell [1], can remove some of the limitations of classical fuel cell reactors as this reactor can operate without the need of an expensive membrane. The electrochemical reactions also benefit from the high surface-to-volume ratio due to the small dimensions of the reactor. The proof-of-concept for cogeneration in this type of fuel cell has been given in [2].

In this work, the reactor operation of the cogeneration microreactor is studied. The electrochemical hydrogenation of nitrobenzene is taken as a case study. This reaction is capable of producing many valuable chemicals, e.g., aniline, p-aminophenol and azoxybenzene. As a counter reaction, the methanol oxidation is used. The performance tested by spontaneous operation of the fuel cell reactor, applying electrical loads of 100Ω and 1000Ω. During operation, the cell, working electrode and counter electrode potentials are continuously monitored. After the experiment, the products that are formed in the reactor are studied in detail by analysing the solution at the outlet. Combining the electrochemical and chemical results, the reactor performance can be interpreted in detail: they provide information on both the efficiency of the process, and on which reactions take place on the electrodes.

Results show that the reactor is capable of conversions up to 64%, and power densities up to 0.299mW cm-2. Higher flow rates have a negative influence on the conversion while having a positive effect on the power density. Both mass transport and crossover phenomena seem to have a substantial influence on the reactor performance. Indeed, it is found that nitrosobenzene is generated in the reactor by cogeneration while aniline is produced at the anode due to oxidant crossover, reducing cogeneration efficiency. The results of this study pave the way for further optimisation of cogeneration microfluidic reactors for the production of fine chemicals.


[1] Ferrigno, R, Stroock, A.D., Clack, T.D, Mayer, M. and Whitesides, G.M., J. Am. Chem. Soc. 124 (2002) 12930-12931
[2] Wouters, B., Hereijgers J., De Malsche W., Breugelmans T., Hubin A., Electrochim. Acta 210 (2016) 337-345
Original languageEnglish
StatePublished - 29 Aug 2017
Event68th Annual Meeting of the International Society of Electrochemistry - Rhode Island Convention Center, Providence, United States
Duration: 27 Aug 20171 Sep 2017
http://annual68.ise-online.org/

Conference

Conference68th Annual Meeting of the International Society of Electrochemistry
CountryUnited States
CityProvidence
Period27/08/171/09/17
Internet address

ID: 35099511