Characterization and Electrocatalytic activity analysis

As-prepared samples measuring 20mm×20mm were utilized as the working anode, while stainless steel plates of the same size served as the cathode, with a distance of 10 mm between them. All degradation experiments operated under a certain stirring speed and 10 mA/cm2 current density. The concentration variations of phenol were determined by UV-Vis spectrophotometry (TU-1810PC, PERSEE) as a function of electrolysis time.

The logarithmic relationship between phenol concentration and electrolysis time was analyzed using a pseudo-first-order kinetics model. The kinetic rate constant (k) of the electrode for phenol degradation was determined using the equation : ln(C0/Ct)=kt, where C0 represents the initial concentration of phenol and Ct is its concentration at a given time t.Electrochemical degradation of phenol on TNTs/SnO2-Sb electrodes with TNTs substrates under different preparation conditions (a) Variations of concentration of phenol with electrolysis time (b) The first-order kinetics curves of phenol degradation was shown in Figure 7.6. The wettability of TNTs substrates were examined by a contact angle test with absolute ethyl alcohol.

SnO2-Sb loading on different substrates was weighed by the balance. The effect of preparation voltage of TNTs arrays on the contact angle of substrate surface and loading amount of SnO2-Sb was shown in Table 3. 7. The surface chemical environment element was analyzed by XPS (PHI5700 ESCA) with Al Kα radiation (hυ=1486.6eV), as shown in Figure 8 and Figure 9, and the XPS analysis of TNTs/SnO2-Sb electrodes with different substrate preparation voltages was shown in Table 4.8. The oxygen vacancy concentration were detected by EPR (Bruker ER200D-SRC) measurement, as shown in Figure 10.9. The presence of hydroxyl radicals (‧OH) generation in a Na2SO4 solution (0.25 mol/L) with terephthalic acid (0.5 mmol/L) as the trapping agent was determined using fluorescence spectroscopy technology (FP-6500, JASCO). The hydroxyl radicals generation ability on the SnO2-Sb electrode with different substrate preparation voltages was shown in Figure 11.10. The reactive radicals generated during electrochemical degradation of organics were detected by using a free radical quenching experiment, with a quencher of p-benzoquinone for ‧OH, and isopropyl alcohol for superoxide radical (‧O2-). The quenching experiment of the active radicals on the SnO2-Sb electrodes with different substrate preparation voltages was shown in Figure 12, and the computed result from the quenching experiment was shown in Table 5.