Cu-Ni bimetallic single atoms supported on TiO2@NG core-shell material for the removal of dibenzothiophene under visible light

Abstract

Cu-Ni bimetallic single atoms supported on core–shell materials of TiO2@N-doped porous graphene were prepared using a precursor dilution strategy. HAADF-STEM and XRD results showed Cu and Ni atoms were uniformly dispersed on the surface of the N-doped porous graphene. XPS revealed the coordination environment of copper and nickel atoms, forming Cu-N4 and Ni-N4, which were conductive to the desulfurization. The photocatalytic performance of the catalysts was evaluated by the removal of dibenzothiophene from the model oil. The effect of the metal loading, temperature, reaction time, and reaction time on the desulfurization ratios was investigated. Experimental results showed the desulfurization activities of 1 wt% TiO2@Cu/Ni-NG was the best. The desulfurization ratios of DBT achieved 100% for 120 min under 30 °C, and the desulfurization ratios could still achieved 98.5% after 10 cycles. With the increase in the metal loading and reaction temperature, desulfurization ratios increased first and then decreased. The kinetics of the desulfurization reaction was established, which showed TiO2@Cu/Ni-NG could reduce the activation energy and accelerate the reaction rate because of the synergistic effect between the Cu and Ni single-atom loaded on the surface of nitrogen-doped graphene. The simple and universal preparation process of TiO2@Cu/Ni-NG makes it have a good application prospect.