Amikam Gidon, Fridman-Bishop Noga, Gendel Youri
Faculty of Civil and Environmental Engineering, The Technion-Israel Institute of Technology, Yitzhak Rabin Building, r625l, Technion City, Haifa 32000, Israel.
ACS Omega. 2020 Dec 7;5(49):31908-31917. doi: 10.1021/acsomega.0c04820. eCollection 2020 Dec 15.
The biochar-assisted water electrolysis process for hydrogen gas production is reported. The H generation is performed in a divided electrolysis cell in which the hydrogen evolution reaction occurs on a cathode and ferrous iron oxidation on an anode. Electrochemically produced Fe(III) species are reduced back to ferrous form in a reaction with biochar concentrated in a packed-bed column through which an acidic anolyte (FeCl) solution is continuously recirculated. During the operation of the proposed process with commercial charcoal, the oxidation of carbon resulted in an accumulation of oxygen-containing groups on the carbon surface that leads to charcoal deactivation. Thermal treatment of the charcoal at 250, 350, and 450 °C in a nitrogen atmosphere resulted in reactivation of carbon, and the best results (≈80% reactivation) were achieved after 3 h of treatment at 450 °C. Nine successful cycles of electrolysis-charcoal regeneration were performed in this study. A ≈98% current efficiency for hydrogen production was achieved at a current density of 50 mA/cm. Much higher current densities can be obtained using the proposed technique as the anodic process of ferrous iron oxidation is decoupled from the carbon oxidation process. The CO production rate achieved in this study was up to 98% of a stoichiometric value proposed for the iron-mediated carbon-assisted water electrolysis process.
报道了用于制氢的生物炭辅助水电解工艺。氢气生成在一个分隔的电解槽中进行，其中析氢反应发生在阴极，亚铁氧化发生在阳极。通过与填充床柱中浓缩的生物炭反应，电化学产生的Fe(III)物种被还原回亚铁形式，酸性阳极电解液（FeCl）溶液通过该填充床柱持续循环。在使用商业木炭的拟议工艺运行过程中，碳的氧化导致碳表面含氧基团的积累，从而导致木炭失活。在氮气气氛中于250、350和450°C对木炭进行热处理导致碳重新活化，在450°C处理3小时后获得了最佳结果（≈80%的再活化率）。本研究进行了9次成功的电解 - 木炭再生循环。在电流密度为50 mA/cm²时，制氢的电流效率达到≈98%。由于亚铁氧化的阳极过程与碳氧化过程解耦，使用该拟议技术可以获得更高的电流密度。本研究中实现的CO生成速率高达铁介导的碳辅助水电解工艺理论值的98%。
