Metal halide perovskite(MHP)has become one of the most promising materials for photocatalytic CO_(2) reduction owing to the wide light absorption range,negative conduction band position and high reduction ability.Howe...Metal halide perovskite(MHP)has become one of the most promising materials for photocatalytic CO_(2) reduction owing to the wide light absorption range,negative conduction band position and high reduction ability.However,photoreduction of CO_(2) by MHP remains a challenge because of the slow charge separation and transfer.Herein,a cobalt single-atom modified nitrogen-doped graphene(Co-NG)cocatalyst is prepared for enhanced photocatalytic CO_(2) reduction of bismuth-based MHP Cs_(3)Bi_(2)Br_(9).The optimal Cs_(3)Bi_(2)Br_(9)/Co-NG composite exhibits the CO production rate of 123.16μmol g^(-1)h^(-1),which is 17.3 times higher than that of Cs_(3)Bi_(2)Br_(9).Moreover,the Cs_(3)Bi_(2)Br_(9)/Co-NG composite photocatalyst exhibits nearly 100% CO selectivity as well as impressive long-term stability.Charge carrier dynamic characterizations such as Kelvin probe force microscopy(KPFM),single-particle PL microscope and transient absorption(TA)spectroscopy demonstrate the vital role of Co-NG cocatalyst in accelerating the transfer and separation of photogenerated charges and improving photocatalytic performance.The reaction mechanism has been demonstrated by in situ diffuse reflectance infrared Fourier-transform spectroscopy measurement.In addition,in situ X-ray photoelectron spectroscopy test and theoretical calculation reveal the reaction reactive sites and reaction energy barriers,demonstrating that the introduction of Co-NG promotes the formation of ^(*)COOH intermediate,providing sufficient evidence for the highly selective generation of CO.This work provides an effective single-atom-based cocatalyst modification strategy for photocatalytic CO_(2) reduction and is expected to shed light on other photocatalytic applications.展开更多
The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an addi...The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an additive to reshape the solvation structure and modulate the interface chemistry.The strong interactions among sorbitol and both water molecules and Zn electrode can reduce the free water activity,optimize the solvation shell of water and Zn^(2+)ions,and regulate the formation of local water(H_(2)O)-poor environment on the surface of Zn electrode,which effectively inhibit the decomposition of water molecules,and thus,achieve the thermodynamically stable and highly reversible Zn electrochemistry.As a result,the assembled Zn/Zn symmetric cells with the sorbitol additive realized an excellent cycling life of 2000 h at 1 mA·cm^(-2)and 1 mAh·cm^(-2),and over 250 h at 5 mA.cm^(-2)and 5 mAh.cm^(-2).Moreover,the Zn/Cu asymmetric cells with the sorbitol additive achieved a high Coulombic efficiency of 99.6%,obtaining a better performance than that with a pure 2 mol-L^(-1)ZnSO_(4)electrolyte.And the constructed Zn/poly1,5-naphthalenediamine(PNDA)batteries could be stably discharged for 2300 cycles at 1 A g^(-1)with an excellent capacity retention rate.This result indicates that the addition of 1 mol-L^(-1)non-toxic sorbitol into a conventional ZnSO_(4)electrolyte can successfully protect the Zn anode interface by improving the electrochemical properties of Zn reversible deposition/decomposition,which greatly promotes its cycle performance,providing a new approach in future development of high performance aqueous Zn ion batteries.展开更多
Metal-organic frameworks（MOFs） are important functional materials. MOF-5（IL）（Zn4O（BDC）3（BDC=1,4-benzenedicarboxylate） was in situ synthesized by the electrochemical method using a tunable ionic liquid（IL）, ...Metal-organic frameworks（MOFs） are important functional materials. MOF-5（IL）（Zn4O（BDC）3（BDC=1,4-benzenedicarboxylate） was in situ synthesized by the electrochemical method using a tunable ionic liquid（IL）, 1-butyl-3-methylimidazolium chloride, as template. The crystallization of distinctly spherical MOF-5（IL） synthsized in ionic liquid by the electrochemical method is attributed to π-π stacking effect, ionic bond, and coordination bond. The analysis results show that the product MOF-5（IL） exhibits better crystallinity and higher thermal stability than MOF-5 generated using the solvothermal method. The cyclic voltammetry reveals that the electrosynthesis reaction is irreversible and controlled by the diffusion. The experiments on methylorange degradation show that the unique structure characteristics of MOF-5（IL） can enhance the photocatalytic ability of Bi OBr. Therefore, MOFs can replace noble metals to improve the photocatalytic properties of bismuth oxyhalide.展开更多
TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocata...TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.展开更多
Charge separation is a crucial problem in photocatalysis.We used a wet‐chemical method to synthesize asymmetrically tipped PdS‐CdSe‐seeded CdS(CdSe@CdS)‐Au nanorod(NR)heterostructures(HCs).In these HCs,electrons a...Charge separation is a crucial problem in photocatalysis.We used a wet‐chemical method to synthesize asymmetrically tipped PdS‐CdSe‐seeded CdS(CdSe@CdS)‐Au nanorod(NR)heterostructures(HCs).In these HCs,electrons and holes are rapidly separated and transported to opposite ends of the NRs by internal electric fields.Their ultraviolet‐visible absorption spectra showed strong electronic coupling between both tips and the CdS body.PdS‐CdSe@CdS‐Au achieved a H2production rate of ca.1100?mol in5h;this is two orders of magnitude greater than the rate achieved with Au‐CdSe@CdS NRs with only one tip.PdS‐CdSe@CdS‐Au NRs can withstand4h of photoirradiation,compared to1.5h for CdSe@CdS NRs,indicating that the photostability of PdS‐CdSe@CdS‐Au is much better than that of CdS.The greatly improved photocatalytic activity and stability are attributed to efficient charge separation and rapid charge transport in the PdS‐CdSe@CdS‐Au HCs.展开更多
文摘Metal halide perovskite(MHP)has become one of the most promising materials for photocatalytic CO_(2) reduction owing to the wide light absorption range,negative conduction band position and high reduction ability.However,photoreduction of CO_(2) by MHP remains a challenge because of the slow charge separation and transfer.Herein,a cobalt single-atom modified nitrogen-doped graphene(Co-NG)cocatalyst is prepared for enhanced photocatalytic CO_(2) reduction of bismuth-based MHP Cs_(3)Bi_(2)Br_(9).The optimal Cs_(3)Bi_(2)Br_(9)/Co-NG composite exhibits the CO production rate of 123.16μmol g^(-1)h^(-1),which is 17.3 times higher than that of Cs_(3)Bi_(2)Br_(9).Moreover,the Cs_(3)Bi_(2)Br_(9)/Co-NG composite photocatalyst exhibits nearly 100% CO selectivity as well as impressive long-term stability.Charge carrier dynamic characterizations such as Kelvin probe force microscopy(KPFM),single-particle PL microscope and transient absorption(TA)spectroscopy demonstrate the vital role of Co-NG cocatalyst in accelerating the transfer and separation of photogenerated charges and improving photocatalytic performance.The reaction mechanism has been demonstrated by in situ diffuse reflectance infrared Fourier-transform spectroscopy measurement.In addition,in situ X-ray photoelectron spectroscopy test and theoretical calculation reveal the reaction reactive sites and reaction energy barriers,demonstrating that the introduction of Co-NG promotes the formation of ^(*)COOH intermediate,providing sufficient evidence for the highly selective generation of CO.This work provides an effective single-atom-based cocatalyst modification strategy for photocatalytic CO_(2) reduction and is expected to shed light on other photocatalytic applications.
基金supported by the National Natural Science Foundation of China(22279063,52001170)Tianjin Natural Science Foundation(22JCYBJC00590)the Fundamental Research Funds for the Central Universities.We thank the Haihe Laboratoryof Sustainable Chemical Transformations for financial support.
文摘The unstable zinc(Zn)/electrolyte interfaces formed by undesired dendrites and parasitic side reactions greatly hinder the development of aqueous zinc ion batteries.Herein,the hydroxy-rich sorbitol was used as an additive to reshape the solvation structure and modulate the interface chemistry.The strong interactions among sorbitol and both water molecules and Zn electrode can reduce the free water activity,optimize the solvation shell of water and Zn^(2+)ions,and regulate the formation of local water(H_(2)O)-poor environment on the surface of Zn electrode,which effectively inhibit the decomposition of water molecules,and thus,achieve the thermodynamically stable and highly reversible Zn electrochemistry.As a result,the assembled Zn/Zn symmetric cells with the sorbitol additive realized an excellent cycling life of 2000 h at 1 mA·cm^(-2)and 1 mAh·cm^(-2),and over 250 h at 5 mA.cm^(-2)and 5 mAh.cm^(-2).Moreover,the Zn/Cu asymmetric cells with the sorbitol additive achieved a high Coulombic efficiency of 99.6%,obtaining a better performance than that with a pure 2 mol-L^(-1)ZnSO_(4)electrolyte.And the constructed Zn/poly1,5-naphthalenediamine(PNDA)batteries could be stably discharged for 2300 cycles at 1 A g^(-1)with an excellent capacity retention rate.This result indicates that the addition of 1 mol-L^(-1)non-toxic sorbitol into a conventional ZnSO_(4)electrolyte can successfully protect the Zn anode interface by improving the electrochemical properties of Zn reversible deposition/decomposition,which greatly promotes its cycle performance,providing a new approach in future development of high performance aqueous Zn ion batteries.
基金Project(U1261103)jointly supported by the National Natural Science Foundation of China and Shenhua Group Corp
文摘Metal-organic frameworks（MOFs） are important functional materials. MOF-5（IL）（Zn4O（BDC）3（BDC=1,4-benzenedicarboxylate） was in situ synthesized by the electrochemical method using a tunable ionic liquid（IL）, 1-butyl-3-methylimidazolium chloride, as template. The crystallization of distinctly spherical MOF-5（IL） synthsized in ionic liquid by the electrochemical method is attributed to π-π stacking effect, ionic bond, and coordination bond. The analysis results show that the product MOF-5（IL） exhibits better crystallinity and higher thermal stability than MOF-5 generated using the solvothermal method. The cyclic voltammetry reveals that the electrosynthesis reaction is irreversible and controlled by the diffusion. The experiments on methylorange degradation show that the unique structure characteristics of MOF-5（IL） can enhance the photocatalytic ability of Bi OBr. Therefore, MOFs can replace noble metals to improve the photocatalytic properties of bismuth oxyhalide.
文摘TiO2 nanosheets mainly exposed （001） facet were prepared through a hydrothermal process with HF as the morphology-directing agent. Ru and RuO2 species were loaded by photo-deposition methods to prepare the photocatalysts. The structural features of the catalysts were characterized by X-ray di raction, transmission electron microscopy, inductively cou-pled plasma atomic emission spectrum, and H2 Temperature-programmed reduction. The photocatalytic property was studied by the O2 evolution from water oxidation, which was examined with respect to the in uences of Ru contents as well as the oxidation and reduction treatments, suggesting the charge separation effect of the Ru species co-catalysts on di erent facets of TiO2 nanosheets. In contrast to Ru/TiO2 and RuO2/TiO2 with the single deposited co-catalyst, the optimized catalyst 0.5%Ru-1.0%RuO2/TiO2 with dual co-catalysts achieved a much improved catalytic performance, in terms of the synergetic effect of dual co-catalysts and the enhanced charge separation effect.
基金supported by the National Key Research and Development Program of China (2016YFE0105700)the National Natural Science Foun-dation of China (21573263)Provincial Fundamental Research Plan of Jiangsu (BK20151236)~~
文摘Charge separation is a crucial problem in photocatalysis.We used a wet‐chemical method to synthesize asymmetrically tipped PdS‐CdSe‐seeded CdS(CdSe@CdS)‐Au nanorod(NR)heterostructures(HCs).In these HCs,electrons and holes are rapidly separated and transported to opposite ends of the NRs by internal electric fields.Their ultraviolet‐visible absorption spectra showed strong electronic coupling between both tips and the CdS body.PdS‐CdSe@CdS‐Au achieved a H2production rate of ca.1100?mol in5h;this is two orders of magnitude greater than the rate achieved with Au‐CdSe@CdS NRs with only one tip.PdS‐CdSe@CdS‐Au NRs can withstand4h of photoirradiation,compared to1.5h for CdSe@CdS NRs,indicating that the photostability of PdS‐CdSe@CdS‐Au is much better than that of CdS.The greatly improved photocatalytic activity and stability are attributed to efficient charge separation and rapid charge transport in the PdS‐CdSe@CdS‐Au HCs.
