Preparation of AAO-CeO₂ nanotubes and their application in electrochemical oxidation desulfurization of diesel

Abstract

The coaxial arrays of AAO-CeO NTs have been successfully galvanostatically deposited on an anode, characterized and adopted as a catalyst for removing organic sulfurs from diesel. The influence of the main electrochemical oxidation factors on the efficiency of desulfurization have also been investigated. The results show that the fabrication process of AAO-CeO NTs is accompanied by the formation of a new phase, namely AlCe, and the main oxidation products of the diesel are soluble inorganic sulphides, especially Ce(SO). When compared with dibenzothiophene and 4, 6-dimethyldibenzothiophene, benzothiophene is much more easily removed, with a removal efficiency that reaches 87.2%. Finally, a possible electrochemical oxidation desulfurization pathway for diesel is proposed.

Study on the Electrochemical Oxidation Desulfurization Behavior of Model Diesel on Anodic Alumina Oxide and Ceria Nanotubes

“…Because the model diesel is composed of pure BT, DBT, and DMDBT, and the supporting electrolyte is only 0.1 M Ce­(NO 3 ) 3 aqueous solution, SO 4 2– can only come from the oxidation of model diesel. Meanwhile, XRD patterns (Figure ) show that, before desulfurization, the main phase compositions of the working electrode are CeO 2 and Al 3 Ce . The peaks at 28.549°, 47.483°, and 56.25° are related to CeO 2 ⟨111⟩, ⟨220⟩, and ⟨311⟩, respectively, and the peaks at 25.281°, 41.880°, and 42.539° are corresponding to Al 3 Ce ⟨110⟩, ⟨112⟩, and ⟨221⟩, respectively.…”

“…The electrochemical oxidation desulfurization experiments of diesel were carried out in a homemade electrolytic cell shown in Figure . Ce­(NO 3 ) 3 aqueous solution (0.1 M) was used as the supporting electrolyte; a large Pt foil was used as the counter electrode; and the working electrode was made up of AAO–CeO 2 NT arrays as used in our previous study . In the electrochemical oxidation process, 20 mL of model diesel was mixed with 80 mL of the above Ce­(NO 3 ) 3 solution by magnetic stirring.…”

“…Nowadays, most studies on EOD are focused on analyzing the influences of electrode materials ,,, or the external factors (such as the temperature, reaction time, or electrolytic voltage) on the desulfurization efficiency, ,, whereas the influence of the sulfide structure itself (such as the bond strength of C–S in sulfides) or the desulfurization modes (desulfurize several sulfides simultaneously or separately) on the desulfurization efficiency has been minimally investigated. However, both the characteristic structure of sulfide and the steric hindrance − between different sulfides will markedly influence the desulfurization efficiency.…”

“…However, both the characteristic structure of sulfide and the steric hindrance − between different sulfides will markedly influence the desulfurization efficiency. Additionally, most studies on oxidation desulfurization of dibenzothiophene (DBT) proposed that the final oxidation product of DBT is DBT sulfone (DBTO 2 ) ,,,,, rather than soluble sulfides SO 4 2– , and only few investigators proposed that adsorbed thiophene can be oxidized to SO 4 2– and CO 2 in acetonitrile and n -Bu 4 NBF 4 at platinum electrodes. , Meanwhile, our previous study found that, when using an anodic alumina oxide and ceria (AAO–CeO 2 ) composite nanotube (NT) array as the anode, the main oxidation product of model diesel is SO 4 2– .…”

Electrochemical oxidation of dibenzothiophene compounds on BDD electrode in acetonitrile–water medium

“…approach to liquid fuel desulfurization [15][16][17][18][19][20]. The ECDS method is advantageous compared to HDS since it is carried out at low reaction temperatures and pressures, in the absence of hydrogen.…”