Ho James, Hershey Matthew, Swearer Dayne F
Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA.
Department of Chemistry, Northwestern University, Evanston, IL, USA.
Phys Chem Chem Phys. 2025 Aug 7;27(31):16435-16446. doi: 10.1039/d5cp01196e.
Mineralization of carbon dioxide is of interest for developing net-negative carbon technologies that mimic natural carbon cycles by removing and sequestering atmospheric carbon dioxide (CO). This study investigates plasma-liquid interactions (PLI) and the impact of modifying electron temperatures of nonthermal CO plasmas to influence the nucleation and growth kinetics of calcium carbonate (CaCO). Through optimization of plasma discharge parameters, we show that plasma-liquid interactions can direct the formation of a pure vaterite phase of CaCO over the more thermodynamically stable calcite phase under certain conditions. By varying the mole fraction of the discharge between a mixture of CO/Ar in the plasma bubbles, we show that increasing electron temperature enhances CO capture, nucleation rate, and CaCO yields. Increasing the electron temperature of the plasma by varying the Ar mole fraction in the flow increases CO conversion nearly tenfold compared to pure CO yet increases the competitive formation of carbon monoxide through CO dissociation. When average electron energies were ∼1 eV, the greatest selectivity toward CaCO was observed. Our results support a mechanistic picture in which CO mineralization is driven concurrently through gas-phase vibrational excitation of CO and at the plasma-liquid interface by generating reactive hydroxyl species from plasma-activated water splitting. These plasma-generated species react to produce HCO, which is the rate-determining step in CO mineralization. By demonstrating accelerated mineralization kinetics and polymorphic control of solid carbonate formation at plasma-liquid interfaces, this study could have broader relevance for engineering net-negative carbon sequestration technologies into solid forms for long-duration storage.
二氧化碳矿化对于开发净负碳技术具有重要意义，这些技术通过去除和封存大气中的二氧化碳（CO₂）来模拟自然碳循环。本研究调查了等离子体-液体相互作用（PLI）以及改变非热CO₂等离子体电子温度对碳酸钙（CaCO₃）成核和生长动力学的影响。通过优化等离子体放电参数，我们表明在某些条件下，等离子体-液体相互作用可以引导形成纯球霰石相的CaCO₃，而不是热力学上更稳定的方解石相。通过改变等离子体气泡中CO₂/Ar混合物放电的摩尔分数，我们表明提高电子温度可增强CO₂捕获、成核速率和CaCO₃产率。通过改变气流中Ar的摩尔分数来提高等离子体的电子温度，与纯CO₂相比，CO₂转化率提高了近十倍，但通过CO₂离解增加了一氧化碳的竞争性形成。当平均电子能量约为1eV时，观察到对CaCO₃的选择性最高。我们的结果支持一种机制，其中CO₂矿化是通过CO₂的气相振动激发以及在等离子体-液体界面通过等离子体激活的水分解产生反应性羟基物种同时驱动的。这些等离子体产生的物种反应生成HCO₃⁻，这是CO₂矿化的速率决定步骤。通过证明在等离子体-液体界面加速矿化动力学和固体碳酸盐形成的多晶型控制，本研究对于将净负碳封存技术工程化为固体形式以进行长期储存可能具有更广泛的相关性。
