Preparation of WO3/g-C3N4 heterojunction catalyst and its oxidative desulfurization performance
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摘要: 以尿素和钨酸铵为原料采用浸渍法制备了金属氧化物三氧化钨(WO3)与石墨相氮化碳(g-C3N4)异质结复合材料WO3/g-C3N4。采用XRD、UV-vis、SEM、PL和XPS表征手段考察了催化剂的理化性质,发现WO3与g-C3N4存在较好的相互作用和电子转移,保证了WO3/g-C3N4本身所具有较高的氧化脱硫活性。以WO3/g-C3N4作为催化剂,过氧化氢异丙苯为氧化剂,考察其光催化氧化脱硫性能,在反应温度80℃,O/S物质的量比为3.0的反应条件下,反应180 min,二苯并噻吩(DBT)转化率可以达到72.79%。通过游离基捕获实验,发现超氧自由基(·O2-)、电子(e-)、羟基自由基(·OH)起到了促进反应速率的作用,并对该体系的反应机理进行了探讨。Abstract: Graphite phase carbon nitride (g-C3N4) and metal oxide tungsten trioxide (WO3) heterojunction nanocomposites WO3/g-C3N4 were prepared by roasting from urea and ammonium tungstate. The physical and chemical properties of the catalysts were investigated by means of XRD, UV-vis, SEM, PL and XPS. The characterization indicated that WO3 and g-C3N4 interacted well in the catalysts, and electron transfer occurred between them, which ensured high oxidative desulfurization activity of WO3/g-C3N4. Supported catalyst WO3/g-C3N4 was prepared using WO3 as the support. Isopropyl peroxide was used as the oxidant to investigate the catalyst performance in oxidative desulfurization of the simulated oil. Under the reaction conditions of 80℃ and the content ratio of O/S at 3, a 72.79% of dibenzothiophene (DBT) conversion could be achieved after 180 min. It was fund that the superoxide free radicals (·O2-), electron (e-) and hydroxyl free radicals (·OH) promoted the reaction rate through free radical capture experiment and the reaction mechanism was proposed.
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Key words:
- WO3 /
- g-C3N4 /
- heterojunction /
- oxidative desulfurization /
- electron transfer
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表 1 不同催化剂的比表面积及其氧化DBT的活性
Table 1 Specific surface area and DBT oxidation activity of different catalysts
Catalyst Specific surface area A/(m2·g-1) DBT conversion x/% WO3 16.40 0 g-C3N4 57.17 1.18 WO3(20%)/g-C3N4 50.23 72.79 WO3(40%)/g-C3N4 41.35 65.4 WO3(60%)/g-C3N4 34.56 16.5 WO3(80%)/g-C3N4 27.62 9.86 reaction conditions: 80 ℃, O/S =3.0, 180 min, the amount of catalyst was 0.1 g -
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