D max rb 12 kw

The morphology of the samples was analyzed by using a Zeiss Supra 40 VP field emission scanning electron microscope (FE-SEM) and FEI Quanta 200 scanning electron microscope (FEI, Hillsboro, OR, USA) operating at 15 kV. The size and morphology were characterized by using a JEOL JEM-2100F transmission electron microscope (JEOL Ltd., Tokyo, Japan) at an accelerating voltage of 200 kV. X-ray diffraction (XRD) patterns were recorded on a Rigaku D/MAX-RB (12 kW; Rigaku, Shibuya-ku, Japan) diffractometer. Fourier-transform infrared spectra (FT-IR) and X-ray photoelectron spectra (XPS) were recorded on Nicolet 380 (Thermo, Waltham, MA, USA) and ESCALab250 (Thermo, Waltham, MA, USA) instruments, respectively. Electrochemical measurements were performed by using an electrochemical workstation (CHI600E, CH Instruments, Austin, TX, USA) with a three-electrode system. The progress of the catalytic reaction was observed by gas chromatography-mass spectrometry (GC/MS; Shimadzu-QP2010 SE, Shimadzu, Kyoto, Japan). All chemicals were used as received without further purification.

Phase identifications of the as-cast samples were determined by XRD (Rigaku DMAX-RB-12KW, Cu-Kα). Microstructures and chemical compositions of the samples were characterized using SEM (Zeiss Auriga, Germany) equipped with an EDS and TEM (Tecnai G2 F20). XPS (AXIS-ULTRA-DLD, Kratos) with an Al Kα (mono, 1486.6 eV) anode at an energy level of 150 W in a vacuum of 10⁻⁷ Pa was employed to investigate the surface chemical states and binding energies of the samples. Individual spectrums were corrected with the reference to C 1s binding energy of eV and then deconvoluted using Gaussian fitting. The contents of various elements including W, Ir, and B were determined by ICP-OES (Prodigy, Leeman).