부산대학교 도서관

MoS2 has drawn great attention as a promising Pt‐substituting catalyst for the hydrogen evolution reaction (HER). This work utilizes H2 as the structure directing agent (SDA) to in situ synthesize a range of Co‐MoS2‐n (n = 0, 0.5, 1.0, 1.4, 2.0) with expanded interlayer spacings (d = 9.2 – 11.1 Å), which significantly boost their HER activities. The Co‐MoS2‐1.4 with an interlayer spacing of 10.3 Å presents an extremely low overpotential of 56 mV (at 10 mA cm−2) and a Tafel slope of 32 mV dec−1, which is superior than most reported MoS2‐based catalysts. Density function theory calculations are used to gain insights that i) the H2 can be dissociatively adsorbed on MoS2 and greatly affect the related surface free energy by regulating the interlayer spacing; ii) the expanded interlayer spacing can significantly decrease the absolute value of ΔGH, thereby leading to greatly promoted HER activity. Additionally, the large amounts of 1T phase (73.9–79.2%) and Co‐Mo‐S active sites (40.9–91.3%) also contribute to the enhanced HER activity of the synthesized samples. Overall, a simple new strategy for in situ synthesis of Co‐MoS2 with an expanded interlayer spacing is proposed, which sheds light on other 2D energy material designs. [ABSTRACT FROM AUTHOR]