Kwon Ik Seon, Kwak In Hye, Kim Ju Yeon, Abbas Hafiz Ghulam, Debela Tekalign Terfa, Seo Jaemin, Cho Min Kyung, Ahn Jae-Pyoung, Park Jeunghee, Kang Hong Seok
Department of Chemistry, Korea University, Sejong 339-700, Republic of Korea.
Nanoscale. 2019 Aug 1;11(30):14266-14275. doi: 10.1039/c9nr04156g.
Two-dimensional (2D) MoS2 nanostructures have been extensively investigated in recent years because of their fascinating electrocatalytic properties. Herein, we report 2D hybrid nanostructures consisting of 1T' phase MoS2 and Fe-phthalocyanine (FePc) molecules that exhibit excellent catalytic activity toward both the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). X-ray absorption spectra revealed an increased Fe-N distance (2.04 Å) in the hybrid complex relative to the isolated FePc. Spin-polarized density functional theory calculations predicted that the Fe center moves toward the MoS2 layer and induces a non-planar structure with an increased Fe-N distance of 2.05 Å, which supports the experimental results. The experiments and calculations consistently show a significant charge transfer from FePc to stabilize the hybrid complex. The excellent HER catalytic performance of FePc-MoS2 is characterized by a low Tafel slope of 32 mV dec-1 at a current density of 10 mA cm-2 and an overpotential of 0.123 V. The ORR catalytic activity is superior to that of the commercial Pt/C catalyst in pH 13 electrolyte, with a more positive half-wave potential (0.89 vs. 0.84 V), a smaller Tafel slope (35 vs. 87 mV·dec-1), and a much better durability (9.3% vs. 40% degradation after 20 h). Such remarkable catalytic activity is ascribed to the HER-active 1T' phase MoS2 and the ORR-active nonplanar Fe-N4 site of FePc.
近年来，二维（2D）二硫化钼（MoS₂）纳米结构因其迷人的电催化性能而受到广泛研究。在此，我们报道了由1T'相MoS₂和铁酞菁（FePc）分子组成的二维混合纳米结构，该结构对析氢反应（HER）和氧还原反应（ORR）均表现出优异的催化活性。X射线吸收光谱显示，相对于孤立的FePc，混合配合物中的Fe-N距离增加（2.04 Å）。自旋极化密度泛函理论计算预测，Fe中心向MoS₂层移动并诱导出非平面结构，Fe-N距离增加到2.05 Å，这与实验结果相符。实验和计算结果一致表明，有大量电荷从FePc转移以稳定混合配合物。FePc-MoS₂优异的HER催化性能表现为在电流密度为10 mA cm⁻²时，塔菲尔斜率低至32 mV dec⁻¹，过电位为0.123 V。在pH 13的电解质中，ORR催化活性优于商业Pt/C催化剂，具有更正的半波电位（0.89对0.84 V）、更小的塔菲尔斜率（35对87 mV·dec⁻¹）和更好的耐久性（20小时后降解9.3%对40%）。这种卓越的催化活性归因于HER活性的1T'相MoS₂和FePc的ORR活性非平面Fe-N₄位点。
