Here we report a temperature-dependent strategy that achieves high-efficiency photocatalytic decarboxylation of long-chain fatty acids to C n-alkanes, e.g., producing ∼0.5 M of n-heptadecane from stearic acid in a single operation with ∼91% selectivity, far beyond no more than mM limit capacities of conventional photocatalysis. Through the use of high boiling-point n-alkane solvents for getting the best self-heating based on the photothermal conversion effect of -FeO, i.e., high temperatures, which force the standing C-chain at low temperatures down onto the -FeO surface for energy-storing, allowing photo-induced hole-electron pairs to readily approach and react with the more strained C-COO bonds. And the consumption of photogenerated electrons shifts from the conventional PCET of the photo-Koble reaction into a step-wise pathway to form more favorable carbanion intermediate that reacting with H into RH is accelerated with lifting temperature. Our work offers a practical approach to upgrade photocatalytic decarboxylation by a convenient photo-to-heat route.

中文翻译：

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α-Fe2O3 上可见光驱动的自热光催化脂肪酸脱羧反应


在这里，我们报告了一种依赖温度的策略，可实现长链脂肪酸高效光催化脱羧为 C 正烷烃，例如，在单次操作中从硬脂酸生产~0.5M 正十七烷，选择性~91%，远远超出传统光催化的不超过mM的极限容量。通过使用高沸点正构烷烃溶剂，基于-FeO的光热转换效应，即高温，迫使低温下的直立C链向下到-FeO表面，获得最佳的自加热效果用于储存能量，使光致空穴电子对能够轻松接近张力更大的 C-COO 键并与其发生反应。光生电子的消耗从光-Koble反应的传统PCET转变为逐步形成更有利的碳负离子中间体，随着温度的升高，与H反应生成RH的速度加快。我们的工作提供了一种通过便捷的光热途径升级光催化脱羧的实用方法。