An Interface‐Controlled Redox Switch for Wastewater Remediation

Abstract

Bipolar junction transistors (BJTs) can function as electrically reversible switches; nevertheless, triggering such circuits requires a distinct voltage bias at the base terminal. Here, we show a proof‐of‐concept of an electrochemical switching device equipped with a redox electrode whose bi‐stable interfacial chemistry, reliant on hydronium ion strength, can provide distinct logic HIGH (1) and logic LOW (0) levels of operation, enabling it to control and command an electronic circuit without the aid of any external voltage input. Electrochemical impedance spectroscopy, quartz crystal microbalance studies, and UV/Vis spectroscopy demonstrate that discrete logic levels are controlled by the solvent‐mediated charge injection/ejection kinetics at the redox‐active half‐cell electrode, leading to a chemically reversible switch with a response time of approximately 1 s and an operating speed of 225 cycles per hour. We demonstrate that the logic HIGH level of the interfacial twin states is actuated when exposed to acid‐contaminated wastewater, automatically triggering the command for remediation.

Current perspectives, challenges, and future directions in the electrochemical detection of microplastics

“…79,80 Chemical sensors are generally designed by combining an electrochemical transducer with embedded identication elements and a sensing substance. 81,82 A chemical or physical change happens when a target molecule interacts with the sensor surface because of the analyte's covalent or non-covalent binding. The target can be either qualitatively or quantitatively detected, owing to the translation of this binding into a readable signal that can be electrochemically tested.…”

Design Strategies and Redox-Dependent Applications of Insoluble Viologen-Based Covalent Organic Polymers

“…This property has been utilized for the preparation of actuators, 19 sensors, 20 drug delivery systems, 21 electrochemical devices, 22 and for environmental applications such as dye, iodine and oxoanion removal. 23 Some of the most extensively studied redox molecular switches are derivatives of 4,4′-bipyridine, also known as viologens. As synthesized, they are positively charged, capable of being reversibly reduced to a radical cationic or neutral species by means of chemical or electrical reductions (Scheme 1).…”

“…A common type of molecular switch incorporated into COPs is a redox switch, which can be altered by a change in the redox potential of its environment. This property has been utilized for the preparation of actuators, sensors, drug delivery systems, electrochemical devices, and for environmental applications such as dye, iodine and oxoanion removal . Some of the most extensively studied redox molecular switches are derivatives of 4,4′-bipyridine, also known as viologens.…”