Dual-atom catalysts(DACs)represent an exciting advance in the field of heterogeneous catalysis.They not only retain the beneficial characteristics of single-atom catalysts(SACs),but they also harness the synergistic e...Dual-atom catalysts(DACs)represent an exciting advance in the field of heterogeneous catalysis.They not only retain the beneficial characteristics of single-atom catalysts(SACs),but they also harness the synergistic effects that arise from the proximity of neighboring single-metal atoms.Nevertheless,the fabrication of heteronuclear dual-atom metals positioned adjacently for use in photocatalysis remains a significant challenge.Herein,we report the atomically dispersed adjacent Pt-Ag dual-atom pairs on carbon nitride(Pt1Ag1-a/CN)by a facile hydrogen-bonding assembly strategy via pyrolysis of the hydrogen-bonding supramolecule containing melamine-Ag and cyanuric acid-Pt complexes on carbon nitride(CN),through which the light absorption depressed by deposited carbonaceous materials during the preparation of dual-atom metals via a traditional method like the pyrolysis of the metal-organic framework.Thanks to the synergism achieved by the bonding interaction of adjacent Pt and Ag single-atom pairs,the developed Pt1Ag1-a/CN with 0.21%Pt loading shows a high turnover frequency(TOF)of 1115 h^(−1)with a H_(2)evolution rate(HER)of 12,000μmol g^(−1)h^(−1)for photocatalytic water splitting under simulated solar light irradiation(325 h^(−1)of TOF with 3480μmol g^(−1)h^(−1)of HER under visible light irradiation).This strategy outperforms the previously reported SACs on CN-based semiconductors.Density functional theory(DFT)calculations demonstrate that the adjacent Ag atom acts as a coordination atom to effectively regulate the electronic structure of the Pt atom and thus brings the d-band center of Pt close to the Fermi energy level,which is beneficial for the H_(2)production.This work presents a facile and general strategy for designing diverse adjacent diatomic cocatalysts in photocatalysis without depressing light absorption by the deposited carbon during the DAC preparation via previously reported methods.展开更多
The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, l...The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron- transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H2-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H2 by Ni-modified TiO2, the formation of NiSx as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO2/Ni-NiSx photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO2 surface and the subsequent formation of NiSx on the Ni surface by a hydrothermal reaction method. It was found that the TiO2/Ni-NiSx photocatalysts exhibited enhanced photocatalytic H2-evolution activity. In particular, TiO2/Ni-NiSx(30%) showed the highest photocatalytic rate (223.74 μmol h.1), which was greater than those of TiO2, TiO2/Ni, and TiO2/NiSx by factors of 22.2, 8.0, and 2.2, respectively. The improved H2-evolution performance of TiO2/Ni-NiSx could be attributed to the excellent synergistic effect of Ni and NiSx, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO2 surface and NiSx serves as interfacial active sites to capture H+ ions from solution and promote the interfacial H2-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.展开更多
Hydrogen energy stands out as one of the most promising alternative energy sources due to its cleanliness and renewability.Electrocatalytic water splitting offers a sustainable pathway for hydrogen production.However,...Hydrogen energy stands out as one of the most promising alternative energy sources due to its cleanliness and renewability.Electrocatalytic water splitting offers a sustainable pathway for hydrogen production.However,the kinetic rate of the hydrogen evolution reaction(HER)is sluggish,emphasizing the critical need for stable and highly active electrocatalysts to facilitate HER and enhance reaction efficiency.Transition metal-based catalysts have garnered attention for their favorable catalytic activity in electrochemical hydrogen evolution in alkaline electrolytes.In this investigation,flower-like nanorods of MoS_(2) were directly synthesized in situ on a nickel foam substrate,followed by the formation of MoP/MoS_(2)-nickel foam(NF)heterostructures through high-temperature phosphating in a tube furnace environment.The findings reveal that MoP/MoS_(2)-NF-450 exhibits outstanding electrocatalytic performance in an alkaline milieu,demonstrating a low overpotential(90 mV)and remarkable durability at a current density of 10 mA/cm^(2).Comprehensive analysis indicates that the introduction of phosphorus(P)atoms enhances the synergistic effect with MoS_(2),while the distinctive flower-like nanorod structure of MoS_(2) exposes more active sites.Moreover,the interface between the MoP/MoS_(2) heterostructure and NF facilitates electron transfer during hydrogen evolution,thereby enhancing electrocatalytic performance.The design and synthesis of such catalysts offer a valuable approach for the development of high-performance hydrogen evolution electrocatalysts.展开更多
Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline ...Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline superstructures(OOCS)with a fixed stoichiometric ratio of Mo_(8)(L)_(2) and high Mo content(>40 wt%)were synthesized using flexible ligands with controllable lengths(named as OOCS-1-3).Then,molybdenum carbides coated with carbon layers as electrocatalysts(Mo_(2)C@C-1-3)can be obtained directly from a one-step high-temperature carbonization process using OOCS-1-3 as precursors.As a typical example,Mo_(2)C@C-3 exhibits satisfactory hydrogen evolution activity with a low overpotential of 151 m V(1.0 mol/L KOH)at 10 m A/cm^(2) and stability for 24 h.The electrocatalytic activity is mainly from the synergistic interactions between the carbon layers and molybdenum carbide species.Furthermore,compared with the initial content of C,N,Mo in OOCS and Mo_(2)C@C,the catalytic activity increases with the N amount.This work makes organic-octamolybdate crystalline superstructures used as general precursors to product high Mo content electrocatalysts applied in energy storage and conversion fields.展开更多
The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are m...The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.展开更多
基金supported by the National Natural Science Foundation of China(grant no.21978030)the National Key R&D Program of China(grant no.2021YFA1502804)the Chinese Ministry of Education via the Program for New Century Excellent Talents in Universities(grant no.NCET-12-0079).
文摘Dual-atom catalysts(DACs)represent an exciting advance in the field of heterogeneous catalysis.They not only retain the beneficial characteristics of single-atom catalysts(SACs),but they also harness the synergistic effects that arise from the proximity of neighboring single-metal atoms.Nevertheless,the fabrication of heteronuclear dual-atom metals positioned adjacently for use in photocatalysis remains a significant challenge.Herein,we report the atomically dispersed adjacent Pt-Ag dual-atom pairs on carbon nitride(Pt1Ag1-a/CN)by a facile hydrogen-bonding assembly strategy via pyrolysis of the hydrogen-bonding supramolecule containing melamine-Ag and cyanuric acid-Pt complexes on carbon nitride(CN),through which the light absorption depressed by deposited carbonaceous materials during the preparation of dual-atom metals via a traditional method like the pyrolysis of the metal-organic framework.Thanks to the synergism achieved by the bonding interaction of adjacent Pt and Ag single-atom pairs,the developed Pt1Ag1-a/CN with 0.21%Pt loading shows a high turnover frequency(TOF)of 1115 h^(−1)with a H_(2)evolution rate(HER)of 12,000μmol g^(−1)h^(−1)for photocatalytic water splitting under simulated solar light irradiation(325 h^(−1)of TOF with 3480μmol g^(−1)h^(−1)of HER under visible light irradiation).This strategy outperforms the previously reported SACs on CN-based semiconductors.Density functional theory(DFT)calculations demonstrate that the adjacent Ag atom acts as a coordination atom to effectively regulate the electronic structure of the Pt atom and thus brings the d-band center of Pt close to the Fermi energy level,which is beneficial for the H_(2)production.This work presents a facile and general strategy for designing diverse adjacent diatomic cocatalysts in photocatalysis without depressing light absorption by the deposited carbon during the DAC preparation via previously reported methods.
基金supported by the National Natural Science Foundation of China(21477094)the Fundamental Research Funds for the Central Universities(WUT 2017IB002)~~
文摘The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron- transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H2-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H2 by Ni-modified TiO2, the formation of NiSx as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO2/Ni-NiSx photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO2 surface and the subsequent formation of NiSx on the Ni surface by a hydrothermal reaction method. It was found that the TiO2/Ni-NiSx photocatalysts exhibited enhanced photocatalytic H2-evolution activity. In particular, TiO2/Ni-NiSx(30%) showed the highest photocatalytic rate (223.74 μmol h.1), which was greater than those of TiO2, TiO2/Ni, and TiO2/NiSx by factors of 22.2, 8.0, and 2.2, respectively. The improved H2-evolution performance of TiO2/Ni-NiSx could be attributed to the excellent synergistic effect of Ni and NiSx, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO2 surface and NiSx serves as interfacial active sites to capture H+ ions from solution and promote the interfacial H2-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.
基金This work was supported by the National Natural Science Foundation of China(Nos.61973223,51972306)the Liaoning Educational Department Foundation,China(Nos.LJKMZ20220762,JYTMS20231510)+1 种基金the Natural Science Foundation of Liaoning Province,China(Nos.2023-MS-235,2023-MSLH-270)the Key Project in Science&Technology of Shenyang University of Chemical Technology,China(No.2023DB005).
文摘Hydrogen energy stands out as one of the most promising alternative energy sources due to its cleanliness and renewability.Electrocatalytic water splitting offers a sustainable pathway for hydrogen production.However,the kinetic rate of the hydrogen evolution reaction(HER)is sluggish,emphasizing the critical need for stable and highly active electrocatalysts to facilitate HER and enhance reaction efficiency.Transition metal-based catalysts have garnered attention for their favorable catalytic activity in electrochemical hydrogen evolution in alkaline electrolytes.In this investigation,flower-like nanorods of MoS_(2) were directly synthesized in situ on a nickel foam substrate,followed by the formation of MoP/MoS_(2)-nickel foam(NF)heterostructures through high-temperature phosphating in a tube furnace environment.The findings reveal that MoP/MoS_(2)-NF-450 exhibits outstanding electrocatalytic performance in an alkaline milieu,demonstrating a low overpotential(90 mV)and remarkable durability at a current density of 10 mA/cm^(2).Comprehensive analysis indicates that the introduction of phosphorus(P)atoms enhances the synergistic effect with MoS_(2),while the distinctive flower-like nanorod structure of MoS_(2) exposes more active sites.Moreover,the interface between the MoP/MoS_(2) heterostructure and NF facilitates electron transfer during hydrogen evolution,thereby enhancing electrocatalytic performance.The design and synthesis of such catalysts offer a valuable approach for the development of high-performance hydrogen evolution electrocatalysts.
基金financially supported by Joint Fund Project of the Natural Science Foundation of Jilin Province(No.YDZJ202301ZYTS290)。
文摘Hydrogen evolution electrocatalysts derived from metal-organic crystalline frameworks can inherit the merits of ordered and adjustable structures with high surface area.In this paper,organic-octamolybdate crystalline superstructures(OOCS)with a fixed stoichiometric ratio of Mo_(8)(L)_(2) and high Mo content(>40 wt%)were synthesized using flexible ligands with controllable lengths(named as OOCS-1-3).Then,molybdenum carbides coated with carbon layers as electrocatalysts(Mo_(2)C@C-1-3)can be obtained directly from a one-step high-temperature carbonization process using OOCS-1-3 as precursors.As a typical example,Mo_(2)C@C-3 exhibits satisfactory hydrogen evolution activity with a low overpotential of 151 m V(1.0 mol/L KOH)at 10 m A/cm^(2) and stability for 24 h.The electrocatalytic activity is mainly from the synergistic interactions between the carbon layers and molybdenum carbide species.Furthermore,compared with the initial content of C,N,Mo in OOCS and Mo_(2)C@C,the catalytic activity increases with the N amount.This work makes organic-octamolybdate crystalline superstructures used as general precursors to product high Mo content electrocatalysts applied in energy storage and conversion fields.
基金the National Natural Science Foundation of China(No.22271203)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(No.KF2021005)the Collaborative Innovation Center of Suzhou Nano Science and Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905).
文摘The coexistence of multi-component active sites like single-atom sites,diatomic sites(DAS)and nanoclusters is shown to result in superior performances in the hydrogen evolution reaction(HER).Metal diatomic sites are more complex than single-atom sites but their unique electronic structures can lead to significant enhancement of the HER kinetics.Although the synthesis and identification of DAS is usually challenging,we report a simple access to a diatomic catalyst by anchoring Co-Ru DAS on nitrogen-doped carbon supports along with Ru nanoparticles(NPs).Experimental and theoretical results revealed the atomic-level characteristics of Co-Ru sites,their strong electronic coupling and their synergy with Ru NPs within the catalyst.The unique electronic structure of the catalyst resulted in an excellent HER activity and stability in alkaline media.This work provides a valuable insight into a widely applicable design of diatomic catalysts with multi-component active sites for highly efficient HER electrocatalysis.
