Badreldin Ahmed, Youssef Karim, El Ghenymy Abdellatif, Wubulikasimu Yiming, Ghouri Zafar Khan, Elsaid Khaled, Kumar Dharmesh, Abdel-Wahab Ahmed
Chemical Engineering Program, Texas A&M University at Qatar, P.O. 23874 Doha, Qatar.
Qatar Shell Service Company W.L.L., P.O. Box 3747 Doha, Qatar.
ACS Omega. 2022 Feb 2;7(6):5521-5536. doi: 10.1021/acsomega.1c06968. eCollection 2022 Feb 15.
Green hydrogen presents itself as a clean energy vector, which can be produced by electrolysis of water by utilizing renewable energy such as solar or wind. While current technologies are sufficient to support commercial deployment of fresh water electrolyzers, there remain a few well-defined challenges in the path of commercializing direct seawater electrolyzers, predominantly related to the sluggish oxygen evolution reaction (OER) kinetics and the competing chlorine evolution reaction (CER) at the anode. Herein, we report the facile and swift fabrication of an S,B-codoped CoFe oxyhydroxide via solution combustion synthesis for the OER with apparent CER suppression abilities. The as-prepared S,B-(CoFe)OOH-H attained ultralow overpotentials of 161 and 278 mV for achieving current densities of 10 and 1000 mA cm, respectively, in an alkaline saline (1 M KOH + 0.5 M NaCl) electrolyte, with a low Tafel slope of 46.7 mV dec. Chronoamperometry testing of the codoped bimetallic oxyhydroxides showed very stable behavior in harsh alkaline saline and in neutral pH saline environments. S,B-(CoFe)OOH-H oxyhydroxide showed a notable decrease in CER production in comparison to the other S,B-codoped counterparts. Selectivity measurements through online FE calculations showed high OER selectivity in alkaline (FE ∼ 97%) and neutral (FE ∼ 91%) pH saline conditions under standard 10 mA cm operation. Moreover, systematic testing in electrolytes at pH values of 14 to 7 yielded promising results, thus bringing direct seawater electrolysis at near-neutral pH conditions closer to realization.
绿色氢能是一种清洁能源载体，可通过利用太阳能或风能等可再生能源对水进行电解来制取。虽然目前的技术足以支持淡水电解槽的商业部署，但在直接海水电解槽商业化的道路上仍存在一些明确的挑战，主要与阳极上缓慢的析氧反应（OER）动力学和竞争性的析氯反应（CER）有关。在此，我们报告了通过溶液燃烧合成法简便快速地制备出一种具有明显抑制CER能力的S、B共掺杂的氢氧化钴铁用于OER。所制备的S、B-(CoFe)OOH-H在碱性盐水（1 M KOH + 0.5 M NaCl）电解液中，分别实现10和1000 mA cm电流密度时的过电位超低，仅为161和278 mV，塔菲尔斜率低至46.7 mV dec。对共掺杂双金属氢氧化物的计时电流法测试表明，在苛刻的碱性盐水和中性pH盐水环境中其行为非常稳定。与其他S、B共掺杂的同类物相比，S、B-(CoFe)OOH-H氢氧化物的CER生成量显著降低。通过在线法拉第效率（FE）计算进行的选择性测量表明，在标准10 mA cm运行条件下，在碱性（FE ∼ 97%）和中性（FE ∼ 91%）pH盐水条件下具有高OER选择性。此外，在pH值为14至7的电解液中进行的系统测试取得了有希望的结果，从而使接近中性pH条件下的直接海水电解更接近实现。
