Preparation of Activated Carbon-SnO₂, TiO₂, and WO₃ Catalysts. Study by FT-IR Spectroscopy

Abstract

The chemical changes produced in the surface of activated carbon as a result of the process of preparation of activated carbon−metal oxide catalysts from SnCl 2 , TiO 2 , and Na 2 WO 4 in water at pH 1.37 for SnCl 2 , 5.84 for TiO 2 , and 9.54 for Na 2 WO 4 are studied. The samples were first prepared by the wet impregnation method in two successive steps of soaking at 80 °C for 5 h and oven-drying at 120 °C for 24 h. Then, they were analyzed by elemental analysis, FT-IR spectroscopy, and measurement of pH of the point of zero charge (pH pzc ). The process yield was 149 wt % with SnCl 2 , 103 wt % with TiO 2 , and 106 wt % with Na 2 WO 4 . The impregnation of the carbon with the catalyst precursors in water entails the oxidation of chromene and pyrone type structures with formation of carboxylic acid groups. pH pzc is 10.50, activated carbon; <1.60, SnCl 2 ; 9.35, TiO 2 ; and 7.90, Na 2 WO 4 . The changes originating in the surface chemistry of AC with influence on the acid−base character are stronger by the order SnCl 2 ≫ Na 2 WO 4 > TiO 2 .

Effect of Activating Agent on the Properties of TiO2/Activated Carbon Heterostructures for Solar Photocatalytic Degradation of Acetaminophen

“…Table 2 summarizes the pH pzc values of the synthesized heterostructures. The pH pzc of bare TiO 2 is almost neutral, which means that its surface is not charged in neutral water [49,50]. In the case of the heterostructures, it is clear that the pH pzc values depend on the activating agent used during the preparation of the activated carbon, corresponding the lowest value to TiO 2 /P-C.…”

Influence of pre-treatment on torrefaction of Phyllostachys edulis

“…The FT-IR spectra of bio-char from the torrefaction of samples was supplied in the supplementary materials. All samples display a wide peak at 3600-3200 cm -1 , which is the stretching vibration peak of -OH in hexagon and hydroxyl in bound water, weakening the peak intensity (Barrosobogeat et al, 2016). Some of these -OH possibly come from carbohydrates in organic matters contained in the pretreated samples and some of them possibly came from water absorbed by the samples.…”

Amino‐Decorated Activated Carbon Fibers with Efficient Static Adsorptivity for Low‐Concentration Formaldehyde Gas in a Confined Space

“…As shown in Figure 2a, peak position changes of VACF-Ns' IR spectra mainly include three new generated characteristic peaks of 660 cm À 1 (ω (N-H) in secondary amide or δ (O = C-N) ), 1064 cm À 1 (ν (C-N) in primary amine), 1637 cm À 1 (ν (C = O) in acylamino) and 2351 cm À 1 (ν (N-H) in ammonium). [22][23][24][25][26] The intensity of peaks at 660 cm À 1 (characteristic peak of secondary amide) and 2351 cm À 1 (characteristic peaks of primary ammonium salt and secondary ammonium salt) becomes stronger gradually with the increase of EDA concentration. The intensity of peak at 1064 cm À 1 (characteristic peak of primary amine) increase first then decrease with EDA concentration increasing, which reach the maximum at 0.5 M concentration.…”