TY - JOUR
T1 - Defect-Driven Optimization of TiO2-Based Electrodes for High-Efficiency Electrochemical 1,4-NADH Generation
AU - Besisa, Nada H.A.
AU - Yoon, Ki Suk
AU - Noguchi, Tomohiro
AU - Kobayashi, Hirokazu
AU - Yamauchi, Miho
N1 - Publisher Copyright:
© 2024 American Chemical Society
PY - 2024/7/1
Y1 - 2024/7/1
N2 - 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.
AB - 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.
KW - active sites engineering
KW - electrochemical reduction
KW - hydrogen spillover
KW - NADH
KW - oxygen vacancy
KW - TiO
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U2 - 10.1021/acssuschemeng.4c02313
DO - 10.1021/acssuschemeng.4c02313
M3 - Article
AN - SCOPUS:85196726490
SN - 2168-0485
VL - 12
SP - 9874
EP - 9881
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
IS - 26
ER -