Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution...Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution to convert N2 to ammonia.However,the poor light absorption and low charge carrier separation efficiency in conventional semiconductors are bottlenecks for the application of this technology.Herein,a facile synthesis of anatase TiO_(2)nanosheets with an abundance of surface oxygen vacancies(TiO_(2)-OV)via the calcination treatment was reported.Photocatalytic experiments of the prepared anatase TiO_(2)samples showed that TiO_(2)-OV nanosheets exhibited remarkably increased ammonia yield for solar-driven N2 fixation in pure water,without adding any sacrificial agents.EPR,XPS,XRD,UV-Vis DRS,TEM,Raman,and PL techniques were employed to systematically explore the possible enhanced mechanism.Studies revealed that the introduced surface oxygen vacancies significantly extended the light absorption capability in the visible region,decreased the adsorption and activation barriers of inert N2,and improved the separation and transfer efficiency of the photogenerated electronhole pairs.Thus,a high rate of ammonia evolution in TiO_(2)-OV was realized.This work offers a promising and sustainable approach for the efficient artificial photosynthesis of ammonia.展开更多
In this work, two kinds of self-assembled hierarchical BiOBr microcrystals were rapidly synthesized through a simple microwave-assisted route in the presence of reactable ionic liquid 1-hexadecyl-3-methylimidazolium b...In this work, two kinds of self-assembled hierarchical BiOBr microcrystals were rapidly synthesized through a simple microwave-assisted route in the presence of reactable ionic liquid 1-hexadecyl-3-methylimidazolium bromide([C_(16)mim]Br). These porous and hollow BiOBr microspheres were obtained via a facile solvothermal method with or without polyvinyl pyrrolidone(PVP), respectively. During the synthetic process, ionic liquid [C_(16)mim]Br played as solvent, reactant and template at the same time. Moreover, the BiOBr hollow and porous microspheres exhibited outstanding photocatalytic activities for the degradation of rhodamine B(RhB) under visible light irradiation. A possible photocatalytic mechanism was also discussed in detail. It can be assumed that the higher photocatalytic activities of BiOBr porous microspheres materials could be ascribed to the novel structure, larger specific surface area, narrower band gap structure and smaller particle size.展开更多
Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the ef-ficient approaches to boost the photocatalytic CO_(−2)conversion efficiency.Herein,ZIF-67-derived porous carbon(P...Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the ef-ficient approaches to boost the photocatalytic CO_(−2)conversion efficiency.Herein,ZIF-67-derived porous carbon(PC)material was employed for the construction of PC@ultrafine Bi_(12)O_(17)Br_(2)nanotubes(PC@BOB NTs)composites through a facile solvothermal synthesis in order to optimize the use of excited elec-trons in the BOB NTs.Photoelectrochemical characterization results revealed that the introduction of PC material achieved a faster charge separation rate in the PC@BOB composites,ensuring more photogener-ated electrons participate in the CO_(−2)adsorption and activation process.Moreover,the pore structures of ZIF-67-derived PC material provided abundant confined spaces for the enrichment of CO_(−2)molecules.Af-ter 5 h of Xenon lamp irradiation,PC@BOB composites exhibited obviously increased photocatalytic CO_(−2)reduction activity in the pure water.When the addition amount of PC was 5 wt%,the PC@BOB-2 com-posite showed the highest CO evolution rate of 359.70μmol/g,which was 2.95 times higher than that of the pure BOB NTs.This work provides some independent insights into the applications of Metal-Organic Framework(MOF)-derived hierarchical porous structures to strengthen the CO_(−2)enrichment,as well as the excited charge utilization efficiency,thus achieving a high solar-to-fuel conversion efficiency.展开更多
Novel carbon quantum dots(CQDs)/Bi OBr composite photocatalysts have been constructed through a facile hydrothermal synthesis in the presence of ionic liquid 1-hexadecyl-3-methylimidazolium bromide([C16 mim]Br). Serie...Novel carbon quantum dots(CQDs)/Bi OBr composite photocatalysts have been constructed through a facile hydrothermal synthesis in the presence of ionic liquid 1-hexadecyl-3-methylimidazolium bromide([C16 mim]Br). Series of characterizations have been performed to confirm the uniform distribution of CQDs in Bi OBr nanosheets and the synergistic effect for photocatalytic degradation organic pollutants between CQDs and Bi OBr. The results show that 3.1 wt% CQDs/Bi OBr photocatalyst possesses the best photocatalytic activity for the degradation of colorless antibiotic tetracycline(TC), endocrine disrupter bisphenol A(BPA) and dye rhodamine B(Rh B), under visible light irradiation, which exhibited the highest photocatalytic performance. The enhanced photocatalytic performance for CQDs/Bi OBr composites could be attributed to the wider optical absorption range and fast separation of photogenerated charge carriers after the introduction of CQDs. The key roles of CQDs for the enhanced photocatalytic activity of Bi OBr have been discussed. A possible mechanism of CQDs/Bi OBr on the enhancement of visible light performance was proposed.展开更多
Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-l...Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-like carbon quantum dots(CQDs)/Bi OBr composite photocatalysts have been prepared via in-situ synthesis by mechanical ball milling in the existence of ionic liquid. The CQDs/Bi OBr composites exhibit higher photo-degradation performance for tetracycline(TC) than Bi OBr monomer and the commercial Bi_(2)O_(3) under visible light irradiation. For comparison, the different Br sources and synthetic methods are chosen to prepare Bi OBr and CQDs/Bi OBr composites. Photocatalysts prepared by ball milling and ionic liquid present significantly enhanced photocatalytic performance for removing TC. In addition, the introduction of CQDs could distinctly enhance the photocatalytic performances of pure Bi OBr. The reason is that CQDs as electron acceptor effectively separate electrons and holes and inhibit their recombination. The intermediates during photocatalytic degradation were tested using liquid chromatography-mass spectrometry(LC-MS) and possible degradation pathways were given. During degradation, ·OH, O_(2)^(·-)and h^(+) were identified to be the main active species based on electron spin resonance(ESR) spectra and free radical trapping experiments. A possible mechanism of CQDs/Bi OBr with enhanced photocatalytic performances was further proposed.展开更多
基金supported by the National Natural Science Foundation of China(No.22108108,22205108,and No.22108106)China Postdoctoral Science Foundation No.2022M721381.
文摘Extremely high-temperature and high-pressure requirement of Haber-Bosch process motivates the search for a sustainable ammonia synthesis approach under mild conditions.Photocatalytic technology is a potential solution to convert N2 to ammonia.However,the poor light absorption and low charge carrier separation efficiency in conventional semiconductors are bottlenecks for the application of this technology.Herein,a facile synthesis of anatase TiO_(2)nanosheets with an abundance of surface oxygen vacancies(TiO_(2)-OV)via the calcination treatment was reported.Photocatalytic experiments of the prepared anatase TiO_(2)samples showed that TiO_(2)-OV nanosheets exhibited remarkably increased ammonia yield for solar-driven N2 fixation in pure water,without adding any sacrificial agents.EPR,XPS,XRD,UV-Vis DRS,TEM,Raman,and PL techniques were employed to systematically explore the possible enhanced mechanism.Studies revealed that the introduced surface oxygen vacancies significantly extended the light absorption capability in the visible region,decreased the adsorption and activation barriers of inert N2,and improved the separation and transfer efficiency of the photogenerated electronhole pairs.Thus,a high rate of ammonia evolution in TiO_(2)-OV was realized.This work offers a promising and sustainable approach for the efficient artificial photosynthesis of ammonia.
基金financially supported by the National Natural Science Foundation of China(21471069,21476098,and 21576123)Jiangsu University Scientific Research Funding(11JDG0146)~~
基金financially supported by the National Natural Science Foundation of China (No. 21476098,21471069 and 21576123)the Doctoral Innovation Fund of Jiangsu Province (KYZZ16_0340)+1 种基金the Science and Technology support program of Zhenjiang (SH2014018)the Natural Science Foundation of Jiangsu Province (BK2012717)
文摘In this work, two kinds of self-assembled hierarchical BiOBr microcrystals were rapidly synthesized through a simple microwave-assisted route in the presence of reactable ionic liquid 1-hexadecyl-3-methylimidazolium bromide([C_(16)mim]Br). These porous and hollow BiOBr microspheres were obtained via a facile solvothermal method with or without polyvinyl pyrrolidone(PVP), respectively. During the synthetic process, ionic liquid [C_(16)mim]Br played as solvent, reactant and template at the same time. Moreover, the BiOBr hollow and porous microspheres exhibited outstanding photocatalytic activities for the degradation of rhodamine B(RhB) under visible light irradiation. A possible photocatalytic mechanism was also discussed in detail. It can be assumed that the higher photocatalytic activities of BiOBr porous microspheres materials could be ascribed to the novel structure, larger specific surface area, narrower band gap structure and smaller particle size.
基金supported by the National Natural Science Foundation of China(Nos.22108108,22108106,22109055)China Postdoctoral Science Foundation(No.2022M721381).
文摘Increasing the utilization efficiency of photogenerated electrons is highly recognized as one of the ef-ficient approaches to boost the photocatalytic CO_(−2)conversion efficiency.Herein,ZIF-67-derived porous carbon(PC)material was employed for the construction of PC@ultrafine Bi_(12)O_(17)Br_(2)nanotubes(PC@BOB NTs)composites through a facile solvothermal synthesis in order to optimize the use of excited elec-trons in the BOB NTs.Photoelectrochemical characterization results revealed that the introduction of PC material achieved a faster charge separation rate in the PC@BOB composites,ensuring more photogener-ated electrons participate in the CO_(−2)adsorption and activation process.Moreover,the pore structures of ZIF-67-derived PC material provided abundant confined spaces for the enrichment of CO_(−2)molecules.Af-ter 5 h of Xenon lamp irradiation,PC@BOB composites exhibited obviously increased photocatalytic CO_(−2)reduction activity in the pure water.When the addition amount of PC was 5 wt%,the PC@BOB-2 com-posite showed the highest CO evolution rate of 359.70μmol/g,which was 2.95 times higher than that of the pure BOB NTs.This work provides some independent insights into the applications of Metal-Organic Framework(MOF)-derived hierarchical porous structures to strengthen the CO_(−2)enrichment,as well as the excited charge utilization efficiency,thus achieving a high solar-to-fuel conversion efficiency.
基金financially supported by the National Natural Science Foundation of China (Nos. 21471069, 21476098 and 21576123)Jiangsu University Scientific Research Funding (No. 11JDG0146)Doctoral Innovation Fund of Jiangsu Province (No. KYCX17_1791)
文摘Novel carbon quantum dots(CQDs)/Bi OBr composite photocatalysts have been constructed through a facile hydrothermal synthesis in the presence of ionic liquid 1-hexadecyl-3-methylimidazolium bromide([C16 mim]Br). Series of characterizations have been performed to confirm the uniform distribution of CQDs in Bi OBr nanosheets and the synergistic effect for photocatalytic degradation organic pollutants between CQDs and Bi OBr. The results show that 3.1 wt% CQDs/Bi OBr photocatalyst possesses the best photocatalytic activity for the degradation of colorless antibiotic tetracycline(TC), endocrine disrupter bisphenol A(BPA) and dye rhodamine B(Rh B), under visible light irradiation, which exhibited the highest photocatalytic performance. The enhanced photocatalytic performance for CQDs/Bi OBr composites could be attributed to the wider optical absorption range and fast separation of photogenerated charge carriers after the introduction of CQDs. The key roles of CQDs for the enhanced photocatalytic activity of Bi OBr have been discussed. A possible mechanism of CQDs/Bi OBr on the enhancement of visible light performance was proposed.
基金financially supported by the National Natural Science Foundation of China (Nos. 22108106, 22108108, 22109055, 21878134)Natural Science Foundation of Jiangsu Province (BK20210742)+2 种基金China Postdoctoral Science Foundation (No. 2020M680065)Hong Kong Scholar Program (No. XJ2021021)Key Laboratory of Electrochemical Energy Storage and Energy Conversion of Hainan Province (No. KFKT2021005)。
文摘Designing simple, efficient, and environmentally friendly methods to construct high-efficient photocatalysts is an important strategy to promote the further development of the field of photocatalysis. Herein, flower-like carbon quantum dots(CQDs)/Bi OBr composite photocatalysts have been prepared via in-situ synthesis by mechanical ball milling in the existence of ionic liquid. The CQDs/Bi OBr composites exhibit higher photo-degradation performance for tetracycline(TC) than Bi OBr monomer and the commercial Bi_(2)O_(3) under visible light irradiation. For comparison, the different Br sources and synthetic methods are chosen to prepare Bi OBr and CQDs/Bi OBr composites. Photocatalysts prepared by ball milling and ionic liquid present significantly enhanced photocatalytic performance for removing TC. In addition, the introduction of CQDs could distinctly enhance the photocatalytic performances of pure Bi OBr. The reason is that CQDs as electron acceptor effectively separate electrons and holes and inhibit their recombination. The intermediates during photocatalytic degradation were tested using liquid chromatography-mass spectrometry(LC-MS) and possible degradation pathways were given. During degradation, ·OH, O_(2)^(·-)and h^(+) were identified to be the main active species based on electron spin resonance(ESR) spectra and free radical trapping experiments. A possible mechanism of CQDs/Bi OBr with enhanced photocatalytic performances was further proposed.
