中山大学韩治际团队报道了稳定制氢的铜-蒽醌分子光催化剂。相关研究成果发表在2024年11月7日出版的《美国化学会杂志》。

在可见光照射下开发制H₂的坚固且廉价的光催化剂，仍然是一个重大挑战。

该研究提出了一系列方形平面铜蒽醌配合物 (R₄N)CuL₂（R=乙基，L=茜素二阴离子（CuAA）；R=正丁基，L=紫精二阴离子（CuPP），（2-羟基蒽醌）甲酰胺二阴离子（CuAHA）），作为分子光催化剂，在可见光驱动的H₂生产中实现高长期稳定性。这些配合物由蒽醌配体自敏化，在没有额外光敏剂或催化剂的情况下用作质子还原光催化剂。

在蓝光照射下，配合物CuAA在H₂O/DMF混合物中产生H₂，其活性在42天内没有减弱，周转数超过6800。电化学和紫外-可见光谱研究与催化循环中的EECC机制（E：电子转移和C：质子化）一致。最初的光化学步骤涉及将蒽醌配体转化为氢醌。

氢醌的进一步光驱动还原，然后是两个质子化步骤，导致H₂的形成。催化速率对H₂O浓度的依赖性表明，通过质子化或CuII-H和H⁺之间的异偶联产生CuII-H中间体，以产生H₂是催化中的周转限制步骤。

附：英文原文

Title: Molecular Copper–Anthraquinone Photocatalysts for Robust Hydrogen Production

Author: Huiqing Yuan, Mei Ming, Shuang Yang, Kai Guo, Bixian Chen, Long Jiang, Zhiji Han

Issue&Volume: November 7, 2024

Abstract: The development of robust and inexpensive photocatalysts for H2 production under visible light irradiation remains a significant challenge. This study presents a series of square planar copper anthraquinone complexes (R4N)CuL2 (R = ethyl, L = alizarin dianion (CuAA); R = n-butyl, L = purpurin dianion (CuPP), (2-hydroxyanthraquinone)formamide dianion (CuAHA)) as molecular photocatalysts to achieve high long-term stability in visible-light-driven H2 production. These complexes are self-sensitized by the anthraquinone ligands and serve as proton reduction photocatalysts without additional photosensitizers or catalysts. Under irradiation of blue light, complex CuAA produces H2 in a mixture of H2O/DMF with undiminished activity over 42 days, giving a turnover number exceeding 6800. Electrochemical and UV–vis studies are consistent with an EECC mechanism (E: electron transfer and C: protonation) in the catalytic cycle. The initial photochemical steps involve conversion of both anthraquinone ligands to hydroquinones. Further light-driven reductions of the hydroquinones followed by two protonation steps results in formation of H2. Dependence of the catalytic rate on the concentration of H2O suggests that either the generation of a CuII–H intermediate by protonation or heterocoupling between CuII–H and H+ to produce H2 is the turnover-limiting step in catalysis.

DOI: 10.1021/jacs.4c11223

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c11223