Liu Yongpeng, Webb Sophie, Moreno-García Pavel, Kulkarni Amogh, Maroni Plinio, Broekmann Peter, Milton Ross D
Department of Inorganic and Analytical Chemistry, University of Geneva, Faculty of Sciences, Quai Ernest-Ansermet 30, Geneva 4 1211, Switzerland.
National Centre of Competence in Research (NCCR) Catalysis, University of Geneva, Quai Ernest-Ansermet 30, Geneva 4 1211, Switzerland.
JACS Au. 2023 Jan 12;3(1):124-130. doi: 10.1021/jacsau.2c00551. eCollection 2023 Jan 23.
Enzymatic electrocatalysis holds promise for new biotechnological approaches to produce chemical commodities such as molecular hydrogen (H). However, typical inhibitory limitations include low stability and/or low electrocatalytic currents (low product yields). Here we report a facile single-step electrode preparation procedure using indium-tin oxide nanoparticles on carbon electrodes. The subsequent immobilization of a model [FeFe]-hydrogenase from ("CpI") on the functionalized carbon electrode permits comparatively large quantities of H to be produced in a stable manner. Specifically, we observe current densities of >8 mA/cm at -0.8 V vs the standard hydrogen electrode (SHE) by direct electron transfer (DET) from cyclic voltammetry, with an onset potential for H production close to its standard potential at pH 7 (approximately -0.4 V vs. SHE). Importantly, hydrogenase-modified electrodes show high stability retaining ∼92% of their electrocatalytic current after 120 h of continuous potentiostatic H production at -0.6 V vs. SHE; gas chromatography confirmed ∼100% Faradaic efficiency. As the bioelectrode preparation method balances simplicity, performance, and stability, it paves the way for DET on other electroenzymatic reactions as well as semiartificial photosynthesis.
酶促电催化有望为生产诸如分子氢（H₂）等化学商品的新生物技术方法提供支持。然而，典型的抑制性限制包括稳定性低和/或电催化电流低（产物产率低）。在此，我们报告了一种在碳电极上使用氧化铟锡纳米颗粒的简便单步电极制备方法。随后将来自嗜热栖热放线菌（“CpI”）的模型[FeFe]-氢化酶固定在功能化碳电极上，能够以稳定的方式产生相对大量的H₂。具体而言，通过循环伏安法中的直接电子转移（DET），我们在相对于标准氢电极（SHE）为 -0.8 V时观察到电流密度>8 mA/cm²，H₂产生的起始电位接近其在pH 7时的标准电位（相对于SHE约为 -0.4 V）。重要的是，氢化酶修饰电极显示出高稳定性，在相对于SHE为 -0.6 V的恒电位下连续产生H₂ 120小时后，仍保留其电催化电流的约92%；气相色谱法证实法拉第效率约为100%。由于生物电极制备方法兼顾了简便性、性能和稳定性，它为其他酶促电化学反应以及半人工光合作用中的直接电子转移铺平了道路。
