Novel SiO2/BiOCl composites were fabricated by decorating BiOCl nanosheets with SiO2 nanoparticles via a simple hydrothermal process. The as-prepared pure BiOCl and SiO2/BiOCl composites were intensively characterized...Novel SiO2/BiOCl composites were fabricated by decorating BiOCl nanosheets with SiO2 nanoparticles via a simple hydrothermal process. The as-prepared pure BiOCl and SiO2/BiOCl composites were intensively characterized by various techniques such as XRD, FT-IR, SEM/TEM, BET, UV-vis, DRS, XPS, and photocurrent measurements. The SiO2/BiOCl composite nanosheets displayed high photocatalytic activity and excellent stability in the degradation of organic pollutants such as phenol, bisphenol A (BPA), and rhodamine B (RhB). With respect to those over bare BiOCl, the degradation rates of RhB, BPA, and phenol over 1.88% SiO2/BiOCl increased 16.5%, 29.0%, and 38.7%, respectively. Radical capturing results suggested that h^+ is the major reactive species and that hydroxyl (·OH) and superoxide (·O2^-) radicals could also be involved in the degradation of organic pollutants. The enhanced photocatalytic performances of SiO2/BiOCl composites can be mainly attributed to the improved texture and the formation of intimate SiO2/BiOCl interfaces, which largely promoted the adsorption of organic pollutants, enhanced the light harvesting, and accelerated the separation of e^– and h^+.展开更多
Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)s...Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)system featuring a Z-scheme In_(2)S_(3)/MnO_(2)/BiOCl heterojunction as a photocathode.This innovative design significantly boosts visible light absorption and facilitates the spatial separation of photogenerated electron-hole pairs.The Z-scheme charge transfer pathway establishes efficient channels for enhancing electron transfer and charge separation,thereby fostering high photocatalytic efficiency.During illumination,photo-generated electrons traverse within the band structure,participating in the Oxygen Reduction Reaction(ORR)during discharging,while photo-induced holes in the valence band facilitate the oxidation reaction of discharge products during the charging process.Under illumination,the surface electrons of In_(2)S_(3)/MnO_(2)/BiOCl modify the morphology of the discharge product(Li_(2)O_(2)),leading to accelerated decomposition kinetics of Li_(2)O_(2)during charging.Remarkably,the In_(2)S_(3)/MnO_(2)/BiOCl photoelectrode exhibits a high specific capacity of 19330 mAh/g under illumination,surpassing performance in the dark by a significant margin.This results in an ultranarrow discharge/charge overpotential of 0.19/0.16 V,coupled with excellent cyclic stability and a long cycle life of 1500 h at 200 mA/g.Further surface tests on the photoelectrode demonstrate that light energy application promotes the decomposition of Li_(2)O_(2),corroborated by density function theory(DFT)theoretical calculations.This study of Z-scheme heterostructured photocathodes sheds light on the mechanism of photo-generated charge carriers in Li–O_(2)batteries,providing valuable insights into their functionality and potential for future battery technologies.展开更多
Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mos...Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3＋ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3＋ ions could be observed, and the UC emission intensity increased with increasing the Zn2＋ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2＋ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2＋ doping could not directly change the special PA emission of BiOCI：Er3＋, but would improve the emission intensity when used as lattice modifier.展开更多
Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,...Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,single Co atoms(Co_(SA))were highly dispersed on hydrothermally synthesized BiOCl nanosheets(BOC)by a facile two-step electrostatic self-assembly and pyrolysis method.The obtained Co_(SA)-BOC could be performed for efficient CO_(2)photoreduction to stoichiometrically produce CO and O_(2)at the ratio of 2:1,with the CO evolution rate reaching 45.93 μmol g^(-1)h^(-1),~4 times that of the pristine BOC.This distinctly improved photocatalytic performance for Co_(SA)-BOC should benefit from the introduction of atomically dispersed Co–O_(4)coordination structures,which could accelerate the migration of photogenerated charge carriers to surface by creating an impurity energy level in the forbidden band,and act as the reactive sites to deliver the photogenerated electrons to activate CO_(2)molecules for CO production.This work provides a facile and reliable strategy to highly disperse single atoms on low-dimensional semiconductors for efficient CO_(2)photoreduction to selectively produce CO.展开更多
Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from th...Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).展开更多
Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composit...Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composite was evaluated using the degradation of rhodamine B(RhB)and tetracycline hydrochloride(TCH)under visible light.The results demonstrated that Ti_(3)C_(2)/BOC composite had higher photocatalytic activity than pure BOC.The optimum incorporation amount of Ti_(3)C_(2) was 2 wt%.The photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC at 10 min to 20 mg/L RhB was 97.6%,which was much higher than that of BOC(75.3%).Similarly,the photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC to 10 mg/L TCH at 30 min was 80.4%,which was higher than BOC(68.1%).In addition,the prepared 2 wt%-Ti_(3)C_(2)/BOC composite also maintained good stability even after four cycles.Electrochemical impedance spectroscopy(EIS),transient photocurrent response(IT)and ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)confirmed that the photoelectrochemical properties of 2 wt%-Ti_(3)C_(2)/BOC composite were significantly improved.On the basis of analyzing the action mechanism of photocatalyst,it was pointed out that·O_(2)^(-)and h~+were the main active substances in the photodegradation of RhB and TCH by 2 wt%-Ti_(3)C_(2)/BOC.展开更多
基金funding from the National Natural Science Foundation of China (21567008, 21707055)the Program for Innovative Research Team of Guangdong University of Petrochemical Technology+4 种基金the Yangfan talents Project of Guangdong Provincethe Innovation-driven “5511” Program in Jiangxi Province (20165BCB18014)the Funding Program for Academic and Technological Leaders of Major Disciplines in Jiangxi Province (20172BCB22018)the Program for New Century Excellent Talents in Fujian Province Universitythe Natural Science Foundation for Distinguished Young Scholars of Hunan Province, China (2017JJ1026)~~
文摘Novel SiO2/BiOCl composites were fabricated by decorating BiOCl nanosheets with SiO2 nanoparticles via a simple hydrothermal process. The as-prepared pure BiOCl and SiO2/BiOCl composites were intensively characterized by various techniques such as XRD, FT-IR, SEM/TEM, BET, UV-vis, DRS, XPS, and photocurrent measurements. The SiO2/BiOCl composite nanosheets displayed high photocatalytic activity and excellent stability in the degradation of organic pollutants such as phenol, bisphenol A (BPA), and rhodamine B (RhB). With respect to those over bare BiOCl, the degradation rates of RhB, BPA, and phenol over 1.88% SiO2/BiOCl increased 16.5%, 29.0%, and 38.7%, respectively. Radical capturing results suggested that h^+ is the major reactive species and that hydroxyl (·OH) and superoxide (·O2^-) radicals could also be involved in the degradation of organic pollutants. The enhanced photocatalytic performances of SiO2/BiOCl composites can be mainly attributed to the improved texture and the formation of intimate SiO2/BiOCl interfaces, which largely promoted the adsorption of organic pollutants, enhanced the light harvesting, and accelerated the separation of e^– and h^+.
基金funded by the Natural Science Project of the Zhengzhou Science and Technology Bureau(No.22ZZRDZX04).
文摘Photo-assisted Li–O_(2)batteries present a promising avenue for reducing overpotential and enhancing the capacity of next-generation energy storage devices.In this study,we introduce a novel photo-assisted Li–O_(2)system featuring a Z-scheme In_(2)S_(3)/MnO_(2)/BiOCl heterojunction as a photocathode.This innovative design significantly boosts visible light absorption and facilitates the spatial separation of photogenerated electron-hole pairs.The Z-scheme charge transfer pathway establishes efficient channels for enhancing electron transfer and charge separation,thereby fostering high photocatalytic efficiency.During illumination,photo-generated electrons traverse within the band structure,participating in the Oxygen Reduction Reaction(ORR)during discharging,while photo-induced holes in the valence band facilitate the oxidation reaction of discharge products during the charging process.Under illumination,the surface electrons of In_(2)S_(3)/MnO_(2)/BiOCl modify the morphology of the discharge product(Li_(2)O_(2)),leading to accelerated decomposition kinetics of Li_(2)O_(2)during charging.Remarkably,the In_(2)S_(3)/MnO_(2)/BiOCl photoelectrode exhibits a high specific capacity of 19330 mAh/g under illumination,surpassing performance in the dark by a significant margin.This results in an ultranarrow discharge/charge overpotential of 0.19/0.16 V,coupled with excellent cyclic stability and a long cycle life of 1500 h at 200 mA/g.Further surface tests on the photoelectrode demonstrate that light energy application promotes the decomposition of Li_(2)O_(2),corroborated by density function theory(DFT)theoretical calculations.This study of Z-scheme heterostructured photocathodes sheds light on the mechanism of photo-generated charge carriers in Li–O_(2)batteries,providing valuable insights into their functionality and potential for future battery technologies.
基金Project supported by the National Natural Science Foundation of China(61465006,61265007)
文摘Effect of divalent dopants, Zn2＋ ion, on the high-order photon avalanche （PA） upconversion （UC） emission of Er3＋ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2＋ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3＋ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3＋ ions could be observed, and the UC emission intensity increased with increasing the Zn2＋ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2＋ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2＋ doping could not directly change the special PA emission of BiOCI：Er3＋, but would improve the emission intensity when used as lattice modifier.
基金the National Natural Science Foundation of China(52225606,52488201)the"Fundamental Research Funds for the Central Universities".
文摘Efficient CO_(2)photoreduction to produce fuel remains a great challenge,due to the fast recombination of photogenerated charge carriers and the lack of effective reactive sites in the developed photocatalysts.Herein,single Co atoms(Co_(SA))were highly dispersed on hydrothermally synthesized BiOCl nanosheets(BOC)by a facile two-step electrostatic self-assembly and pyrolysis method.The obtained Co_(SA)-BOC could be performed for efficient CO_(2)photoreduction to stoichiometrically produce CO and O_(2)at the ratio of 2:1,with the CO evolution rate reaching 45.93 μmol g^(-1)h^(-1),~4 times that of the pristine BOC.This distinctly improved photocatalytic performance for Co_(SA)-BOC should benefit from the introduction of atomically dispersed Co–O_(4)coordination structures,which could accelerate the migration of photogenerated charge carriers to surface by creating an impurity energy level in the forbidden band,and act as the reactive sites to deliver the photogenerated electrons to activate CO_(2)molecules for CO production.This work provides a facile and reliable strategy to highly disperse single atoms on low-dimensional semiconductors for efficient CO_(2)photoreduction to selectively produce CO.
基金the financial support from the National Key R&D Program of China(2024YFF0506100)the National Natural Science Foundation of China(52225606 and 52488201).
文摘Given the limited exposure of active sites and the retarded separation of photogenerated charge carriers in those developed photocata-lysts,photocatalyticCO_(2)splitting into value-added chemicals has suffered from the poor activity and remained in great challenge for real application.Herein,hydrothermally synthesized BiOCl with layered structure(BOC-NSs)was exfoliated into thickness reduced nanosheets(BOCNSs-w)and even atomic layers(BOCNSs-i)via ultrasonication in water and isopro-panol,respectively.In comparison with the pristine BOCNSs,the exfoli-ated BiOCl,especially BOCNSs-i with atomically layered structure,exhibits much improved photocatalytic activity forCO_(2)overall splitting to produce CO andO_(2) at a stoichiometric ratio of 2:1,with CO evolution rate reaching 134.8µmolg^(-1)h^(-1) under simulated solar light(1.7 suns).By surpassing the photocatalytic performances of the state-of-the-artBi_(l)O_(m)X_(n)(X:Cl,Br,I)based photocatalysts,the CO evolution rate is further increased by 99 times,reaching 13.3 mmolg^(-1)h^(-1) under concentrated solar irradiation(34 suns).This excellent photocatalytic performance achieved over BOCNSs-i should be benefited from the shortened transfer distance and the increased built-in electric field intensity,which acceler-ates the migration of photogenerated charge carriers to surface.Moreover,with oxygen vacancies(VO)introduced into the atomic layers,BOCNSs-i is exposed with the electrons enriched Bi active sites that could transfer electrons to activateCO_(2)molecules for highly efficient and selective CO production,by lowering the energy barrier of rate-determining step(RDS),*OH+*CO_(2)-→HCO_(3)-.It is also realized that theH_(2)O vapor supplied during photocatalytic reaction would exchange oxygen atoms withCO_(2),which could alter the reaction path-ways and further reduce the energy barrier of RDS,contributing to the dramatically improved photocatalytic performance forCO_(2)overall splitting to CO andO_(2).
基金Funded by the National Natural Science Foundation of China(Nos.52102110 and 42272355)the China Postdoctoral Science Foundation(No.2023M732724)。
文摘Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composite was evaluated using the degradation of rhodamine B(RhB)and tetracycline hydrochloride(TCH)under visible light.The results demonstrated that Ti_(3)C_(2)/BOC composite had higher photocatalytic activity than pure BOC.The optimum incorporation amount of Ti_(3)C_(2) was 2 wt%.The photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC at 10 min to 20 mg/L RhB was 97.6%,which was much higher than that of BOC(75.3%).Similarly,the photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC to 10 mg/L TCH at 30 min was 80.4%,which was higher than BOC(68.1%).In addition,the prepared 2 wt%-Ti_(3)C_(2)/BOC composite also maintained good stability even after four cycles.Electrochemical impedance spectroscopy(EIS),transient photocurrent response(IT)and ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)confirmed that the photoelectrochemical properties of 2 wt%-Ti_(3)C_(2)/BOC composite were significantly improved.On the basis of analyzing the action mechanism of photocatalyst,it was pointed out that·O_(2)^(-)and h~+were the main active substances in the photodegradation of RhB and TCH by 2 wt%-Ti_(3)C_(2)/BOC.
