4.5 Material properties
The morphologies of the MoSe2 samples were observed through scanning electron microscopy (SEM, Philips, XL30 ESEM-FEG) at the MEMS Sensor Platform Center of SungKyunKwan University (SKKU). The microstructures of the samples were monitored by field-emission TEM (FE-TEM, JEOL LTD, JEM-2100F) at an accelerating voltage of 200 kV. To exactly observe Pt cluster on the MoSe2-I-36h-Pt, a focused ion beam (FIB, FEI, Quanta 3D FEG) was selected. Elemental analysis of Mo, Se, and Pt was conducted using inductively coupled plasma mass spectrometry (ICP-MS, PerkinElmer, NexION2000). Phase identification of as-synthesized MoSe2 samples was performed using multiple-purpose X-ray diffraction (XRD, Rigaku, SmartLab 9kW) with Cu Kα source (λ = 0.15406 nm, 45 kV, 200 mA) in the range of 10–90°. In the case of MoSe2-I samples, grazing-incidence XRD method at an 0.5° was chosen to avoid the strong intensity of a substrate. The surface states were characterized using a Raman spectrometer (HORIBA, LabRam HR Evolution) with 532 nm laser in the range of 100–400 cm-1 and X-ray photoelectron spectroscopy (XPS, Vg Scienta, EASC 2000) with an Al anode.