Eguchi Daichi, Sakamoto Masanori, Teranishi Toshiharu
Department of Chemistry , Graduate School of Science , Kyoto University , Gokasho , Uji , Kyoto 611-0011 , Japan.
Institute for Chemical Research , Kyoto University , Gokasho , Uji , Kyoto 611-0011 , Japan . Email:
Chem Sci. 2017 Nov 3;9(1):261-265. doi: 10.1039/c7sc03997b. eCollection 2018 Jan 7.
The "ligand effect" can be used as a novel strategy for enhancing the catalytic properties of metal clusters. Herein, we report the ligand effect of porphyrin derivatives on gold clusters (AuCs, size <2 nm) and gold nanoparticles (AuNPs, size >2 nm) in the electrochemical hydrogen evolution reaction (HER) at pH 6.7. The current density of porphyrin face-coordinated AuCs at -0.4 V reversible hydrogen electrode (RHE) was 460% higher than that of phenylethanethiol-protected AuCs. X-ray photoemission spectroscopy indicated that the approach of porphyrin to the Au surface induced charge migration from the porphyrin to the Au core, leading to a shift in the 5d state of AuCs that resulted in enhanced HER activities. This ligand effect is pronounced in the cluster region due to the large surface-to-volume ratio. These results pave the way for enhancing catalytic activity of metal clusters using ligand design.
“配体效应”可作为一种增强金属簇催化性能的新策略。在此，我们报道了卟啉衍生物在pH 6.7的电化学析氢反应（HER）中对金簇（AuCs，尺寸<2 nm）和金纳米颗粒（AuNPs，尺寸>2 nm）的配体效应。在-0.4 V可逆氢电极（RHE）下，卟啉面配位的AuCs的电流密度比苯乙硫醇保护的AuCs高460%。X射线光电子能谱表明，卟啉靠近金表面会引起电荷从卟啉迁移到金核，导致AuCs的5d态发生位移，从而增强了析氢活性。由于表面积与体积比大，这种配体效应在簇区域很明显。这些结果为利用配体设计提高金属簇的催化活性铺平了道路。
