Miniaturized Carbon Fiber Paper Electrodes for In Situ High Resolution NMR Analyses

Abstract

Combining spectroscopic techniques with electrochemistry is a promising strategy, as it allows the detailed investigation of the species that are consumed and produced by the reaction in real time. However, as with any in situ coupling technique, the junction between NMR and electrochemistry presents some challenges, notably the distortion of NMR signals due to the placement of electrodes close to or within the detection region. In this work, miniaturized electrodes made of carbon fiber paper were developed and later modified with platinum. Platinum decoration by cathodic deposition was chosen, as platinum is a prominent element in electrocatalysis, able to catalyze a large variety of reactions. To evaluate the efficiency of this electrochemical system, the oxidation of ascorbic acid was used as a model reaction. It was observed that the electrodes caused substantial signal distortion when placed within the detection region (full width at half-maximum equal to 1.46 Hz), whereas no distortion was observed when the electrodes were placed 1 mm above the detection region (full width at half-maximum equal to 0.95 Hz). With this system, it was also possible to monitor the magnetoelectrolysis effect, caused by the interaction of the magnetic field with the flowing ions, leading to a doubling of the ascorbic acid oxidation rate, compared to the reaction performed without a magnetic field. In addition to its low cost and simplicity in preparation, the developed electrode system allows the electrode surface to be easily modified with other suitable catalysts.

Compact In Situ Electrochemical NMR with Wireless and Anti-interference Strategy in Multiscenario Applications

“…Many efforts, including our own, have been dedicated to making real-time NMR measurement of electrochemical reactions accessible, − and full cycle monitoring has been successfully accomplished, , contributing to a deeper understanding of electrochemical processes. However, despite well-designed shielding setups, NMR still faces challenges such as increased noise and susceptibility to external radio frequency (RF) signals, including those from broadcasting and mobile radio communication within the defined frequency ranges, after introducing the electrodes with additional and external connections into the magnet. , Moreover, realizing the full potential of NMR for in vitro and in vivo methodologies within practical matrices has not yet been fully achieved in this context …”