The electrochemical reduction of carbon dioxide (CO 2 ) is investigated in acetonitrile with tetrabutylammonium perchlorate as an electrolyte using a lead cathode and a sacrificial zinc anode, and the product under such a setup is insoluble zinc oxalate at potentials between −2.2 and −2.8 V vs. Ag rod electrode. Preelectrolysis is an effective method to remove the water in the electrolyte, which makes a distinct reduction peak of CO 2 appear at −2.6 V vs. Ag on cyclic voltammogram. Even trace amounts of water in the electrolyte can interfere with the faradaic efficiency of reduction of CO 2 to oxalate, and the product could be β-ZnC 2 O 4 (in anhydrous solution) or ZnC 2 O 4 · 2H 2 O (if water exists). The faradaic efficiency for oxalate production also depends on the cathode potential and the temperature, and the maximum is 96.8 % at −2.6 V vs. Ag and 5 °C. This is the highest value of CO 2 electrochemical reduction found in the literature under ambient pressure.
In this paper, the feasibility of electrolysis of Cu2S and FeS in sulfur-containing carbon saturated iron melt aided by liquid lead cathode is studied by cyclic voltammetry and potentiostatic electrolysis at 1300 °C. The Cu2S and FeS are electro-reduced on the lead cathode and the product copper dissolve into the liquid lead while the product iron dissolves into iron melt due to the difference of solubility. An insert graphite rod in iron melt was used as the anode, on which the S2− is oxidized to S. This finding provides a new way for refining sulfide impurities in iron-based melt.
Tianqi Wang,Qi Wang,Guangqi Hu,Kaihui Liu,Jianguo Gu,Changmei Zhang,Dinghai Wang,Bin-dong Li
The scalable electrochemical reduction of nitroaromatics to anilines remains challenging for industrial implementation. This work addresses this limitation through the design and optimization of three continuous-flow microreactors: sink-type, one-channel, and multi-channel series flow cells. Employing a CuSn7Pb15 cathode and acidic methanol/water electrolyte, the multi-channel series flow cell achieved exceptional performance under optimized conditions (200 mM substrate, 30 mA cm −2 , 25 mL min −1 flow rate), attaining 97 % yield, 85 % Faradaic efficiency (FE), and a remarkable space-time yield (STY) of 146 g·L −3 ·h −1 —30-fold higher than a batch reactor. Kinetic studies revealed a diffusion-controlled, two-step first-order mechanism at high current density, but a two-step zero-order mechanism at low current density. Computational fluid dynamics (CFD) and residence time distribution (RTD) analyses confirmed superior flow uniformity and thinner boundary layers in this design. Hammett studies demonstrated accelerated kinetics for electron-deficient nitroaromatics. Scalability was proven via a decagram-scale synthesis of 3-(trifluoromethyl)aniline (95 % yield, 72 % FE). This work establishes flow electroreduction as a safe, efficient, and industrially viable route to anilines.
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