A novel route for preparing Gd₂O₂S:Eu³⁺ phosphor using high-sulfur petroleum coke as a sulfur source

In this paper, high-sulfur petroleum coke was used as the sulfur source and Gd2O2S powder was prepared by sulfurization of the Gd2O3 powder synthesized by homogeneous precipitation method. Gd2O2S:Eu3+ phosphor was also prepared by the same process. And the phase and morphology of the as-prepared product were studied by X-ray powder diffraction (XRD) and field emission scanning electron microscope (FE-SEM) techniques. The results indicated that the sulfurization product at 1000 celcius is single phase Gd2O2S with quasi spherical shape when the Gd3+ ion concentration is only at 0.01 mol center dot L-1. Here the pyrolysis gases during high-temperature pyrolysis are evaluated by combining with high-temperature thermogravimetric analysis (TG), infrared analysis (IR), and mass spectrometry (MS). The results show that the petroleum coke pyrolysis gases are CO, H2O, CO2, H2S, SO2, and H-2, roughly consistent with those of sample mass loss. In addition, the formation mechanism of Gd2O2S is also proposed. PL excitation and emission spectra show that when the concentration of Eu(3+ )ion is 9%, the PL excitation intensity is the strongest, and concentration quenching occurs. Under excitation at 321 nm light, the red emission of the Gd2O2S:9%Eu3+ phosphor has the strongest peak at 626 nm, which is attributed to the D-5(0) -> (7)F2 transition of the Eu3+ ion.