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Fabrication of heterojunction MnTiO3–TiO2-decorated carbon nanofibers via electrospinning as an effective multifunctional photocatalyst

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Fig. 1

(A, B) SEM and FESEM images of the electrospun MnAc/TIIP/PVP nanofibers mat after drying at 60°C for 24 h. (C, D) SEM and FESEM images of the calcined nanofibers at 800°C in Ar atmosphere. PVP, polyvinylpyrrolidone
(A, B) SEM and FESEM images of the electrospun MnAc/TIIP/PVP nanofibers mat after drying at 60°C for 24 h. (C, D) SEM and FESEM images of the calcined nanofibers at 800°C in Ar atmosphere. PVP, polyvinylpyrrolidone

Fig. 2

Size distribution of the nanofibers before calcination (A) and after calcination (B)
Size distribution of the nanofibers before calcination (A) and after calcination (B)

Fig. 3

XRD patterns of the powders obtained from the calcination of MnAc/TIIP/PVP at 800°C in Ar atmosphere. CNFs, carbon nanofibers; PVP, polyvinylpyrrolidone
XRD patterns of the powders obtained from the calcination of MnAc/TIIP/PVP at 800°C in Ar atmosphere. CNFs, carbon nanofibers; PVP, polyvinylpyrrolidone

Fig. 4

(A) TEM image of a single calcined nanofiber along with the TEM EDX line analysis, (B–E) corresponding to Ti, C, O, and Mn TEM EDX line analyses. EDX, energy-dispersive X-ray spectroscopy
(A) TEM image of a single calcined nanofiber along with the TEM EDX line analysis, (B–E) corresponding to Ti, C, O, and Mn TEM EDX line analyses. EDX, energy-dispersive X-ray spectroscopy

Fig. 5

The photodegradation profile of MB dye (200 mg·L−1, Ci = 5 mg·L−1, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers; MB, methylene blue
The photodegradation profile of MB dye (200 mg·L−1, Ci = 5 mg·L−1, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers; MB, methylene blue

Fig. 6

(A) Effect of MB on the photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) modified LH plot for MB photodegradation (200 mg·L−1, T = 298 K, and I = 25 W·m−2). LH, Langmuir Hinshelwood; MB, methylene blue
(A) Effect of MB on the photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) modified LH plot for MB photodegradation (200 mg·L−1, T = 298 K, and I = 25 W·m−2). LH, Langmuir Hinshelwood; MB, methylene blue

Fig. 7

(A) Effect of reaction temperature on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) Arrhenius plot for MB photodegradation (200 mg·L−1, Ci = 5 mg·L−1, and I = 25 W·m−2). MB, methylene blue
(A) Effect of reaction temperature on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) Arrhenius plot for MB photodegradation (200 mg·L−1, Ci = 5 mg·L−1, and I = 25 W·m−2). MB, methylene blue

Fig. 8

(A) Effect of light intensity on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) plot of K3 vs. I (200 mg·L−1, Ci = 5 mg L−1, and T = 298 K). MB, methylene blue
(A) Effect of light intensity on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) plot of K3 vs. I (200 mg·L−1, Ci = 5 mg L−1, and T = 298 K). MB, methylene blue

Fig. 9

(A) Effect of catalyst amount on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) Langmuir-type plot for photodegradation of MB (Ci = 5 mg·L−1, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers; MB, methylene blue
(A) Effect of catalyst amount on photodegradation of MB, (B) plot of ln Ci/Cf vs. time, and (C) Langmuir-type plot for photodegradation of MB (Ci = 5 mg·L−1, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers; MB, methylene blue

Fig. 10

Comparison between experimental and predicted Kapp values
Comparison between experimental and predicted Kapp values

Fig. 11

H2 generation in the presence of various photocatalysts (200 mg·L−1, Ci = 0.1 M, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers
H2 generation in the presence of various photocatalysts (200 mg·L−1, Ci = 0.1 M, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers

Fig. 12

(A) Effect of photocatalyst dosage on H2 generation, and (B) plot of logarithmic value of the hydrogen production rate vs. logarithmic value of the catalyst amount (Ci = 0.1 M, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers
(A) Effect of photocatalyst dosage on H2 generation, and (B) plot of logarithmic value of the hydrogen production rate vs. logarithmic value of the catalyst amount (Ci = 0.1 M, T = 298 K, and I = 25 W·m−2). CNFs, carbon nanofibers

Fig. 13

(A) Effect of AB concentration on H2 production, and (B) plot of the logarithmic value of the H2 production rate vs. logarithmic value of the AB amount (200 mg·L−1, T = 298 K, and I = 25 W·m−2). AB, ammonia–borane
(A) Effect of AB concentration on H2 production, and (B) plot of the logarithmic value of the H2 production rate vs. logarithmic value of the AB amount (200 mg·L−1, T = 298 K, and I = 25 W·m−2). AB, ammonia–borane

Fig. 14

(A) Effect of the reaction temperature on H2 production, and (B) plot of logarithmic value of hydrogen production rate constant vs. (1/T) (200 mg·L−1, Ci = 0.1 M, and I = 25 W·m−2)
(A) Effect of the reaction temperature on H2 production, and (B) plot of logarithmic value of hydrogen production rate constant vs. (1/T) (200 mg·L−1, Ci = 0.1 M, and I = 25 W·m−2)

Fig. 15

Effect of light intensity on H2 production (A) and logarithmic value of the H2 generation rate vs. logarithmic value of light intensity (B) (200 mg·L−1, Ci = 0.1 M, and T = 298 K)
Effect of light intensity on H2 production (A) and logarithmic value of the H2 generation rate vs. logarithmic value of light intensity (B) (200 mg·L−1, Ci = 0.1 M, and T = 298 K)

Fig. 16

Scheme for the creation and influence of electrons and holes in the photocatalytic degradation of MB and photohydrolysis of AB. AB, ammonia–borane; CB, conduction band; CNFs, carbon nanofibers; MB, methylene blue; VB, valence band
Scheme for the creation and influence of electrons and holes in the photocatalytic degradation of MB and photohydrolysis of AB. AB, ammonia–borane; CB, conduction band; CNFs, carbon nanofibers; MB, methylene blue; VB, valence band

Reaction rate constants of MB photodegradation at various MB concentrations, reaction temperatures, light intensities, and MnTiO3/TiO2@CNFs dosages

Rate constant (min−1) MB dye concentration (Ci) (mg · L−1)

0.0153 5
0.0088 7.5
0.0068 10
0.0044 15

Rate constant (min−1) Reaction temperature (T) (°C)

0.0153 25 T
0.0166 30
0.0188 35
0.0222 40

Rate constant (min−1) Light intensity (I) (W·m−2)

0.0153 25 I
0.0166 30
0.019 35
0.0228 40

Rate constant (min−1) Catalyst dosage (CNFs) (mg·L−1)

0.0153 200
0.0216 400
0.027 600
0.0324 800

Values of various constants obtained by employing multiple regression analysis in model equation

Parameter k′ KR (L mg−1) Ea (J mol−1) R (J K−1 mol−1) m (m2 W−1 min−1) KNFs (L mg−1)
Value 3.7551 × 104 4.99 1.9204 × 104 8.314 6 × 10−4 2.444 × 10−3
eISSN:
2083-134X
Langue:
Anglais