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Caption : photoluminiscent spectra of a suspension of znnp and gox (both in aqueous phase), d1-w all these with λ<sub>ex</sub> = 325 nm and for comparison it is shown the nh4oh solution emission spectra. the peak at 325 nm for znnp and gox is the raleyigh peak of water. note that the higher emission is for the d1-t confirming the interaction of the amine groups and the gqd

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Caption : photoluminiscent spectra from znnp in aqueous phase (green dashed line) and its mixture with a 10<sup>-10 m</sup> h<sub>2</sub>o<sub>2</sub> solution (green solid line). these samples were excited at 275 and 325 nm. observe that the znnp (green dashed line), with λ<sub>ex</sub> = 275 nm has an emission (although not as intense as d1-t) and the presence of h<sub>2</sub>o<sub>2</sub> (green solid line) inhibits its fluorescence. the λ<sub>ex</sub> = 325 nm for the znnp (brown dashed line) and znnp + h<sub>2</sub>o<sub>2</sub> (brown solid lines) have not photoluminiscent property. the spectra of the 10<sup>-10 m</sup> m h<sub>2</sub>o<sub>2</sub> solution with λ<sub>ex</sub> = 338 nm (blue solid line) with λ<sub>ex</sub> = 400 nm (blue dashed line) have not fluorescence and thus this property from gqd-znnp only depends on their interaction and synergy

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Caption : sem images from the precursor (a) graphite (gf), (c) graphene oxide (gox) and from (e) graphene quantum dots of d2-w. the micrography (b), (d) and (f) are magnification from the red square from (a), (b) and (c), respectively. it can be observed a modification in the morphology from the graphite where the particles are stacked and the reduction in the particle size and change in morphology in gox. from gox to gqd there is also a reduction in size and the gdq tend to form circles of around 1 μm formed by particles which are les tan 100 nm

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Caption : sem images from the precursor (a) graphite (gf), (c) graphene oxide (gox) and from (e) graphene quantum dots of d2-w. the micrography (b), (d) and (f) are magnification from the red square from (a), (b) and (c), respectively. it can be observed a modification in the morphology from the graphite where the particles are stacked and the reduction in the particle size and change in morphology in gox. from gox to gqd there is also a reduction in size and the gdq tend to form circles of around 1 μm formed by particles which are les tan 100 nm

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Caption : sem images from the precursor (a) graphite (gf), (c) graphene oxide (gox) and from (e) graphene quantum dots of d2-w. the micrography (b), (d) and (f) are magnification from the red square from (a), (b) and (c), respectively. it can be observed a modification in the morphology from the graphite where the particles are stacked and the reduction in the particle size and change in morphology in gox. from gox to gqd there is also a reduction in size and the gdq tend to form circles of around 1 μm formed by particles which are les tan 100 nm

File Name : fig_s3d_gox.png

Caption : sem images from the precursor (a) graphite (gf), (c) graphene oxide (gox) and from (e) graphene quantum dots of d2-w. the micrography (b), (d) and (f) are magnification from the red square from (a), (b) and (c), respectively. it can be observed a modification in the morphology from the graphite where the particles are stacked and the reduction in the particle size and change in morphology in gox. from gox to gqd there is also a reduction in size and the gdq tend to form circles of around 1 μm formed by particles which are les tan 100 nm

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Caption : sem images from the precursor (a) graphite (gf), (c) graphene oxide (gox) and from (e) graphene quantum dots of d2-w. the micrography (b), (d) and (f) are magnification from the red square from (a), (b) and (c), respectively. it can be observed a modification in the morphology from the graphite where the particles are stacked and the reduction in the particle size and change in morphology in gox. from gox to gqd there is also a reduction in size and the gdq tend to form circles of around 1 μm formed by particles which are les tan 100 nm

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Caption : photoluminiscent spectra from graphene oxide (gox) samples varying its concentrations according to table s1. the wavelength of excitation was (a) 250 nm and (b) 275 nm and the spectra was measured in aqueous phase. it is observed a shift to higher wavelengths as the concentration of gox increases

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Caption : gox wasted after hydrothermal synthesis by route 2 (low nh<sub>4</sub>oh concentration during the synthesis). the solid retained after filtering was air environment dried over the night and the xrd was done the next day. the xrd shows two characteristics peaks from reduced graphene oxide (rgo) which are at 2θ= 24.7° corresponding to (002) plane and other at 2θ= 47.8° from (102) plane <sup>1,2</sup>. the peaks at 2θ= 54.9° from (004) plane correspond to crystalline structure of graphite<sup>3</sup> and peaks at 2θ= 32.7°, 38.2 and 65.5 ° might be related with soot formations due to high temperature synthesis <sup>4</sup>

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Caption : scheme of the residual solid from the synthesis of d1-w. the remaining solid from this sample was weighted (with an excess of humidity and nh<sub>4</sub>oh the mass was 0.0230 g) and it was transferred into a beaker and later 1 ml of h<sub>2</sub>o<sub>2</sub> and 7 ml of deionized water were added; this was well stirred and were introduced into an autoclave at 170 °c for 6 h. the sample then was filtered, and the liquid was conserved and named sd1-w. a photoluminescent spectra was done to this liquid and this is shown in figure s7

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Caption : photoluminescence emission spectra measured in aqueous phase to compare the samples sd1-w (synthesized as the method in scheme of figure s6) with d1-w and h-gox. the values inside each graphic for every band of emission are the excitation wavelengths. nevertheless, the spectra from sd1-w and d1-w are very similar in intensity, whilst the spectra from h-gox are not. for this reason, it is proved that once the amine groups are incorporated to the gqd and to the graphene oxide from sd1-w, the h<sub>2</sub>o<sub>2</sub> is not enough to break the structure as it does with graphene oxide from h-gox

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Caption : (a) photoluminescence emission spectra from nanocomposite zd1-t used as a h<sub>2</sub>o<sub>2</sub> probe; the λ<sub>ex</sub> was 275 nm. (b) data (red circles) obtained from the emission intensity at λ<sub>ex</sub> = 385 nm; data fit (green line) properly (r<sup>2</sup> = 0.99) with the quadratic equation <i>i</i> = 1696.48c<sup>2</sup>-293.75c+71.41 , where <i>i</i> is the emission intensity in arbitrary units and <i>i</i> is the h<sub>2</sub>o<sub>2</sub> concentration in moles per liter.

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Caption : (a) photoluminescence emission spectra from nanocomposite zd1-t used as a h<sub>2</sub>o<sub>2</sub> probe; the λ<sub>ex</sub> was 275 nm. (b) data (red circles) obtained from the emission intensity at λ<sub>ex</sub> = 385 nm; data fit (green line) properly (r<sup>2</sup> = 0.99) with the quadratic equation <i>i</i> = 1696.48c<sup>2</sup>-293.75c+71.41 , where <i>i</i> is the emission intensity in arbitrary units and <i>i</i> is the h<sub>2</sub>o<sub>2</sub> concentration in moles per liter.