Effect of the carbon loading on the structural and photocatalytic properties of reduced graphene oxide-TiO2 nanocomposites prepared by hydrothermal synthesis
“…This diffraction line has been associated with the (110) crystal plane of rutile [ 25 ]. The pure TiO 2 sample showed anatase as the main crystalline phase (XRD pattern not shown here), which is in line with previous studies [ 25 , 27 , 28 ]. Figure 1 XRD patterns of the samples obtained in this work.…”
Section: Resultssupporting
confidence: 93%
“…( 9 ) [ 67 ]. The sol–gel route used here usually gives rise to anatase nanoparticles [ 27 , 28 ]. Although the formation of rutile on HKUST-1 could be unexpected, it may be ascribed to the acidification of the solution during the transformation of Cu 3 (BTC) 2 into Cu 2 (BTC)(OH)(H 2 O), as evidenced in Eq.…”
Section: Discussionmentioning
confidence: 99%
“…Gonçalves et al . [ 27 , 28 ] loaded sol–gel-derived TiO 2 nanoparticles on reduced graphene oxide nanosheets. In this work, metal–organic frameworks (MOFs) were used as support to grow TiO 2 nanoparticles.…”
Organic pollutants have been a significant source of concern in recent years due to their facile dissemination and harmful effects. In this work, two different metal–organic frameworks (MOFs) were initially prepared by hydrothermal treatment, namely aluminum trimesate (MIL-100(Al)) and copper trimesate (HKUST-1). These materials were subsequently submitted to a post-synthetic modification step to grow titania nanoparticles on their surface. Anatase nanoparticles with sizes around 5 nm were successfully anchored on MIL-100(Al), and the concentration of TiO
2
in this sample was about 68 wt.%. This is the first time that this composite (TiO
2
@MIL-100(Al)) is reported in the literature. It showed an improved photocatalytic activity, removing 90% of methylene blue (
k
app
= 1.29 h
−1
), 55% of sodium diclofenac (
k
app
= 0.21 h
−1
), and 62% of ibuprofen (
k
app
= 0.37 h
−1
) after four hours of illumination with UV-A light. A significant concentration (14 µM) of reactive oxygen species (ROS) was detected for this composite. HKUST-1 showed a structural collapse during its post-synthetic modification, leading to a non-porous material and providing fewer sites for the heterogeneous nucleation of titania. This behavior led to a low concentration of rutile nanoparticles on HKUST-1 (9 wt.%). However, the obtained composite (TiO
2
@HKUST) also showed an improved photoactivity compared to HKUST-1, increasing the photodegradation rates evaluated for methylene blue (0.05 h
−1
vs. 0.29 h
−1
), sodium diclofenac (negligible vs. 0.03 h
−1
), and ibuprofen (0.01 h
−1
vs. 0.02 h
−1
). This work brings new insights concerning the preparation of photocatalysts by growing semiconductor nanoparticles on trimesate-based MOFs.
“…This diffraction line has been associated with the (110) crystal plane of rutile [ 25 ]. The pure TiO 2 sample showed anatase as the main crystalline phase (XRD pattern not shown here), which is in line with previous studies [ 25 , 27 , 28 ]. Figure 1 XRD patterns of the samples obtained in this work.…”
Section: Resultssupporting
confidence: 93%
“…( 9 ) [ 67 ]. The sol–gel route used here usually gives rise to anatase nanoparticles [ 27 , 28 ]. Although the formation of rutile on HKUST-1 could be unexpected, it may be ascribed to the acidification of the solution during the transformation of Cu 3 (BTC) 2 into Cu 2 (BTC)(OH)(H 2 O), as evidenced in Eq.…”
Section: Discussionmentioning
confidence: 99%
“…Gonçalves et al . [ 27 , 28 ] loaded sol–gel-derived TiO 2 nanoparticles on reduced graphene oxide nanosheets. In this work, metal–organic frameworks (MOFs) were used as support to grow TiO 2 nanoparticles.…”
Organic pollutants have been a significant source of concern in recent years due to their facile dissemination and harmful effects. In this work, two different metal–organic frameworks (MOFs) were initially prepared by hydrothermal treatment, namely aluminum trimesate (MIL-100(Al)) and copper trimesate (HKUST-1). These materials were subsequently submitted to a post-synthetic modification step to grow titania nanoparticles on their surface. Anatase nanoparticles with sizes around 5 nm were successfully anchored on MIL-100(Al), and the concentration of TiO
2
in this sample was about 68 wt.%. This is the first time that this composite (TiO
2
@MIL-100(Al)) is reported in the literature. It showed an improved photocatalytic activity, removing 90% of methylene blue (
k
app
= 1.29 h
−1
), 55% of sodium diclofenac (
k
app
= 0.21 h
−1
), and 62% of ibuprofen (
k
app
= 0.37 h
−1
) after four hours of illumination with UV-A light. A significant concentration (14 µM) of reactive oxygen species (ROS) was detected for this composite. HKUST-1 showed a structural collapse during its post-synthetic modification, leading to a non-porous material and providing fewer sites for the heterogeneous nucleation of titania. This behavior led to a low concentration of rutile nanoparticles on HKUST-1 (9 wt.%). However, the obtained composite (TiO
2
@HKUST) also showed an improved photoactivity compared to HKUST-1, increasing the photodegradation rates evaluated for methylene blue (0.05 h
−1
vs. 0.29 h
−1
), sodium diclofenac (negligible vs. 0.03 h
−1
), and ibuprofen (0.01 h
−1
vs. 0.02 h
−1
). This work brings new insights concerning the preparation of photocatalysts by growing semiconductor nanoparticles on trimesate-based MOFs.
“…RGO was approximately 1 wt% in all the Cs 2 AgBiBr 6 -RGO composites, which is known to be optimal in RGO-photocatalyst composites. 29 The optimum DP-Cu-RGO composite contains 1 wt% Cu-RGO content with an optimal 5 wt% of Cu content in Cu-RGO (Fig. S10a †).…”
Section: Resultsmentioning
confidence: 99%
“…RGO was approximately 1 wt% in all the Cs 2 -AgBiBr 6 -RGO composites, which is known to be optimal in RGO-photocatalyst composites. 29 A physical mixture of Cs 2 -AgBiBr 6 and Cu-RGO was also prepared by simply mixing the powders in the same mass ratio. Cs 2 AgBiBr 6 is sometimes abbreviated in legends as DP for double perovskite.…”
Pb-based halide perovskites have recently showed great potential in various applications such as solar cells, optoelectronics and photocatalysis. Despite their high performance, the Pb2+ toxicity along with poor stability hinder...
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