Ultralow-weight loading Ni catalyst supported on two-dimensional vermiculite for carbon monoxide methanation

摘要

Nickel-based catalysts represent the most commonly used systems for CO methanation.We have successfully prepared a Ni catalyst system supported on two-dimensional plasma-treated vermiculite(2D-PVMT)with a very low Ni loading(0.5 wt%).The catalyst precursor was subjected to heat treatment via either conventional heat treatment(CHT)or the plasma irradiation method(PIM).The as-obtained CHT-Ni/PVMT and PIM-Ni/PVMT catalysts were characterized with scanning electron microscopy(SEM),energy dispersive X-ray(EDX),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),inductively coupled plasma-atomic emission spectroscopy(ICP-AES)and high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM).Additionally,CHT-NiO/PVMT and PIM-NiO/PVMT catalysts were characterized with hydrogen temperature programmed reduction(H_2-TPR).Compared with CHT-Ni/PVMT,PIM-Ni/PVMT exhibited superior catalytic performance.The plasma treated catalyst PIM-Ni/PVMT achieved a CO conversion of93.5%and a turnover frequency(TOF)of 0.8537 s^(-1),at a temperature of 450°C,a gas hourly space velocity of 6000 ml·g^(-1)·h^(-1),a synthesis gas flow rate of 65 ml·min^(-1),and a pressure of 1.5 MPa.Plasma irradiation may provide a successful strategy for the preparation of catalysts with very low metal loadings which exhibit excellent properties.