The electrochemical reduction of nicotinamide adenine dinucleotide (NAD) using water as a hydrogen source is a promising strategy for the efficient and environmentally friendly production of the active enzymatic cofactor 1,4-NADH, which is a key for the further application of enzymatic systems in various industrial fields. However, the efficient regeneration of 1,4-NADH (NADH-reg) remains a major challenge. The rate-limiting step in the electrochemical conversion of the oxidized NAD is the second electron transfer to an NAD radical, which is formed by the reduction of NAD⁺, at a large overpotential, whereas the other side reactions proceed readily. To surmount this obstacle and promote NADH-reg, we used Ni nanoparticle-loaded TiO₂ on a Ti electrode (Ni-TOT) containing a sufficient number of defects as active sites, which are formed at 300 °C in the H₂ atmosphere. Ni-TOT facilitated the formation of enzymatically active 1,4-NADH with a superior yield and significantly reduced overpotential compared to those on untreated TOT. We found that hydrogen spillover promotes the formation of active sites on Ni-TOT. This study highlights the potential of engineered defect-enriched electrodes as a means to advance NADH-reg.

中文翻译：

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用于高效电化学 1,4-NADH 生成的 TiO2 基电极的缺陷驱动优化


以水为氢源电化学还原烟酰胺腺嘌呤二核苷酸（NAD）是一种高效、环保生产活性酶辅因子 1,4-NADH 的有前景的策略，也是酶系统进一步应用的关键。各个工业领域。然而，1,4-NADH（NADH-reg）的有效再生仍然是一个重大挑战。氧化NAD电化学转化的限速步骤是在较大的过电势下，第二次电子转移到NAD自由基，该自由基是由NAD ⁺ 还原形成的，而其他副反应则进行容易。为了克服这一障碍并促进 NADH-reg，我们在含有足够数量的缺陷作为活性位点的 Ti 电极（Ni-TOT）上使用了负载 Ni 纳米粒子的 TiO ₂ ，该电极在 300 °C 下形成在 H ₂ 气氛中。与未经处理的 TOT 相比，Ni-TOT 促进了具有酶活性的 1,4-NADH 的形成，产量较高，并且显着降低了过电势。我们发现氢溢出促进了 Ni-TOT 上活性位点的形成。这项研究强调了工程缺陷富集电极作为推进 NADH-reg 的一种手段的潜力。