We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rathe...We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.展开更多
In this contribution, a novel high-temperature CO_2 adsorbent consisting of Mg-Al layered double hydroxide （LDH） and graphene oxide （GO） nanosheets was prepared and evaluated. The nanocomposite-type adsorbent was ...In this contribution, a novel high-temperature CO_2 adsorbent consisting of Mg-Al layered double hydroxide （LDH） and graphene oxide （GO） nanosheets was prepared and evaluated. The nanocomposite-type adsorbent was synthesized based on the electrostatically driven self-assembly between positively charged Mg-Al LDH single sheet and negatively charged GO monolayer. The characteristics of this novel adsorbent were investigated using XRD, FE-SEM, HRTEM, FT-IR, BET and TGA. The results showed that both the CO_2 adsorption capacity and the multi- cycle stability of LDH were increased with the addition of GO owing to the enhanced particle dispersion and stabilization. In particular, the absolute CO_2 capture capacity of LDH was increased by more than twice by adding 6.54 wt% GO as support. GO appeared to be especially effective for supporting LDH sheets. Moreover, the CO_2 capture capacity of the adsorbent could be further increased by doping with 15 wt% K_2CO_3. This work demonstrated a new approach for the preparation of LDH-based hybrid-type adsorbents for CO2 capture.展开更多
The fluorescence quenching of Rhodamine 6G （R6G） by graphene oxide （GO） was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl g...The fluorescence quenching of Rhodamine 6G （R6G） by graphene oxide （GO） was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl groups on the GO nanosheet turned to play a dominant role in quenching the R6G fluorescence. The quenching in the static regime can be described by the ＂sphere of action＂ model. The significant absorption of the R6G fluorescence by the ground-state complex formed between R6G and GO was identified to be responsible for the static quenching mechanisms in quenching. This work offers the R6G/GO system. insights into the fluorescence展开更多
We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific singl...We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific single-stranded oligonucleotides colorimetrically.By exploiting the tendency of the H-GNS to aggregate under high ionic strength and their inherent catalytic activities,excess H-GNS were removed and the amount of H-GNs remaining in the supernatant was quantified.Subsequently,the binding affinity of hemin-binding DNA aptamers to the H-GNS was determined upon titration with the DNA.With the conformity of the experimental data to the Langmuir adsorption isotherm,hemin is hypothesized to be sandwiched between the G-quadruplex DNA and graphene forming a ternary complex as a result of the specific bind-ing of the aptamer with the H-GNS.The binding affinity of the aptamer is not as strong as that of hemin/G-quadruplex in solution,which is attributed to electronic effects imparted by the graphene surface.The catalytic activity of the resulting complex,however,was confirmed to be higher than that of H-GNs alone.展开更多
基金This work was supported by the National Basic Research Program of China （No.2010CB923300）, the National Natural Science Foundation of China （No.91127042 and No.21173205）, the Chinese Academy of Sciences （No.XDB01020000）, the FR- FCUC （No.WK2340000012）, the USTC-NSRL Joint Funds （No.KY2340000021）, and the National Under- graduate Innovative Training Program of Ministry of Education （No.201210358064）.
文摘We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.
基金supported by the Fundamental Research Funds for the Central Universities(BLYJ201509)the Fundamental Research Funds for the Central Universities(TD-JC-2013-3)+4 种基金the Program for New Century Excellent Talents in University(NCET-12-0787)Beijing Nova Programme(Z131109000413013)the National Natural Science Foundation of China(51308045)the Foundation of State Key Laboratory of Coal Conversion(Grant No.J14-15-309)Institute of Coal Chemistry,Chinese Academy of Sciences
文摘In this contribution, a novel high-temperature CO_2 adsorbent consisting of Mg-Al layered double hydroxide （LDH） and graphene oxide （GO） nanosheets was prepared and evaluated. The nanocomposite-type adsorbent was synthesized based on the electrostatically driven self-assembly between positively charged Mg-Al LDH single sheet and negatively charged GO monolayer. The characteristics of this novel adsorbent were investigated using XRD, FE-SEM, HRTEM, FT-IR, BET and TGA. The results showed that both the CO_2 adsorption capacity and the multi- cycle stability of LDH were increased with the addition of GO owing to the enhanced particle dispersion and stabilization. In particular, the absolute CO_2 capture capacity of LDH was increased by more than twice by adding 6.54 wt% GO as support. GO appeared to be especially effective for supporting LDH sheets. Moreover, the CO_2 capture capacity of the adsorbent could be further increased by doping with 15 wt% K_2CO_3. This work demonstrated a new approach for the preparation of LDH-based hybrid-type adsorbents for CO2 capture.
基金supported by the Ministry of Science and Technology of China (No.2016YFA0200602)the National Natural Science Foundation of China (No.21573211 and No.21633007)the Fundamental Research Funds for the Central Universities (No.WK2340000063)
文摘The fluorescence quenching of Rhodamine 6G （R6G） by graphene oxide （GO） was interrogated by R6G fluorescence measurements using a set of controlled GO samples with varied C/O ratios as the quencher. The carbonyl groups on the GO nanosheet turned to play a dominant role in quenching the R6G fluorescence. The quenching in the static regime can be described by the ＂sphere of action＂ model. The significant absorption of the R6G fluorescence by the ground-state complex formed between R6G and GO was identified to be responsible for the static quenching mechanisms in quenching. This work offers the R6G/GO system. insights into the fluorescence
基金the financial supports of Natural Sciences and Engineering Research Council(NSERC)of Canada and National Natural Science Foundation of China(no.21775095)。
文摘We demonstrate herein that hemin-graphene hybrid nanosheets(H-GNs)can differentiate hemin-binding DNA aptamers(i.e.,guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin)and nonspecific single-stranded oligonucleotides colorimetrically.By exploiting the tendency of the H-GNS to aggregate under high ionic strength and their inherent catalytic activities,excess H-GNS were removed and the amount of H-GNs remaining in the supernatant was quantified.Subsequently,the binding affinity of hemin-binding DNA aptamers to the H-GNS was determined upon titration with the DNA.With the conformity of the experimental data to the Langmuir adsorption isotherm,hemin is hypothesized to be sandwiched between the G-quadruplex DNA and graphene forming a ternary complex as a result of the specific bind-ing of the aptamer with the H-GNS.The binding affinity of the aptamer is not as strong as that of hemin/G-quadruplex in solution,which is attributed to electronic effects imparted by the graphene surface.The catalytic activity of the resulting complex,however,was confirmed to be higher than that of H-GNs alone.
