The Cr-Mo-N films were deposited on high speed steel（HSS） substrates by a DC reactive magnetron sputtering equipment coupled with two horizontal magnetron sources.The effects of substrate negative bias voltage（Vb）...The Cr-Mo-N films were deposited on high speed steel（HSS） substrates by a DC reactive magnetron sputtering equipment coupled with two horizontal magnetron sources.The effects of substrate negative bias voltage（Vb）,substrate temperature（Ts） and gas flow ratio（R= N2/（N2+ Ar）） on the microstructure,morphology,as well as the mechanical and tribological properties of the Cr-Mo-N films were investigated by virtue of X-ray diffraction（XRD） analysis,X-ray photoelectron spectroscopy（XPS）,field emission scanning electron microscopy（FESEM）,atomic force microscopy（AFM）,nano-indentation test,ball-on-disk tribometer,and Rockwell indenter et al.With increasing Vbto-100 V,the preferred orientation of the films changed from（111） to（200） and their mechanical and tribological properties were improved gradually,too.It was also found that Tsgave a significant effect on mechanical property enhancement.When the Tsreached 300 ℃,the film obtained the highest hardness and effective elastic modulus of approximately 30.1 and 420.5 GPa,respectively and its critical load increased to about 54 N.With increasing R,the phase transformation from body-centered-cubic（bcc） Cr and hexagonal CrMoNxmultiphase to single face-centered-cubic（fcc） solid solution phase was observed.The correlations between values of hardness（H）,effective elastic modulus（E*）,HIE*,H3/E*2,elastic recovery（1/14） and tribological properties of the films were also investigated.The results showed that the elastic recovery played an important role in the tribological behavior.展开更多
Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages ...Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.展开更多
A novel photocatalytic cocatalyst, MoC quantum dots integrated into N-doped carbon microflowers (MoC–NC), was synthesized, establishing a key Mo–N interfacial bond. The Mo–N bond's regulation was achieved by ad...A novel photocatalytic cocatalyst, MoC quantum dots integrated into N-doped carbon microflowers (MoC–NC), was synthesized, establishing a key Mo–N interfacial bond. The Mo–N bond's regulation was achieved by adjusting the pH of Mo-polydopamine precursor solutions. A composite photocatalyst, MoC–NC/CdS (MNS), was formed by in situ growth of nano-CdS on MoC–NC. The pH during synthesis, crucial for Mo–N bond formation, significantly influenced Cr(Ⅵ) reduction and H_(2) evolution performance. The optimal MNS, created at pH 9.0, demonstrated 99.2% reduction efficiency for Cr(Ⅵ) in 20 min and H_(2) evolution rate of 11.4 mmol g^(-1) h^(-1) over 3 h, outperforming Pt/CdS. Mechanistic studies and density functional theory revealed MoC–NC's role in enhancing light absorption, reaction kinetics, and electron transport, attributing to its ultra-small quantum dots and abundant Mo–N bonds.展开更多
基金supported by the National Key Basic Research Program of China (973 Program, No. 2012CB625100)the National Natural Science Foundation of China (NSFC, No. 51171197)the Natural Science Foundation of Liaoning Province of China (No. 2013020093)
文摘The Cr-Mo-N films were deposited on high speed steel（HSS） substrates by a DC reactive magnetron sputtering equipment coupled with two horizontal magnetron sources.The effects of substrate negative bias voltage（Vb）,substrate temperature（Ts） and gas flow ratio（R= N2/（N2+ Ar）） on the microstructure,morphology,as well as the mechanical and tribological properties of the Cr-Mo-N films were investigated by virtue of X-ray diffraction（XRD） analysis,X-ray photoelectron spectroscopy（XPS）,field emission scanning electron microscopy（FESEM）,atomic force microscopy（AFM）,nano-indentation test,ball-on-disk tribometer,and Rockwell indenter et al.With increasing Vbto-100 V,the preferred orientation of the films changed from（111） to（200） and their mechanical and tribological properties were improved gradually,too.It was also found that Tsgave a significant effect on mechanical property enhancement.When the Tsreached 300 ℃,the film obtained the highest hardness and effective elastic modulus of approximately 30.1 and 420.5 GPa,respectively and its critical load increased to about 54 N.With increasing R,the phase transformation from body-centered-cubic（bcc） Cr and hexagonal CrMoNxmultiphase to single face-centered-cubic（fcc） solid solution phase was observed.The correlations between values of hardness（H）,effective elastic modulus（E*）,HIE*,H3/E*2,elastic recovery（1/14） and tribological properties of the films were also investigated.The results showed that the elastic recovery played an important role in the tribological behavior.
基金financially supported by the National Natural Science Foundation of China(No.51762021)the Natural Science Foundation of Jiangxi province(Nos.20224ACB204008,20242BAB25223,and 20242BAB25248)the Special Funding Program for Graduate Student Innovation of Jiangxi Province(No.YC2024-S594)。
文摘Optimizing the interfacial environments of electrodes has emerged as an effective strategy to improve their electrochemical properties.Amorphous/crystalline interfacial coupling can effectively utilize the advantages of amorphous materials to optimize the interfacial structure for efficient Na^(+)storage.Herein,the dense homologous amorphous/crystalline heterointerfaces are in situ achieved in N-doped carbon nanobundles via self-polymerization and precise nitriding(Mo–N/Mo_(2)N@C).The amorphous Mo–N rich in unsaturated vacancy defects provides abundant active sites with isotropic ion-transport channels,and can effectively alleviate structural stress from crystalline Mo_(2)N.Meanwhile,the conductive Mo_(2)N can facilitate effective electron transfer,augmented further by the carbon encapsulation.Theoretical calculations reveal that the dense heterointerfaces can optimize the electronic structure and shift the d-p orbital centers of Mo and N upward,thereby enhancing the adsorption and mobility of Na^(+),and ultimately improving the charge transport and storage efficiency of the electrode.The Mo–N/Mo_(2)N@C as an anode delivers a 46.9%increase in reversible capacity over Mo_(2)N@C,reaching 461.1 m Ah.g^(–1)at 0.1 A.g^(–1),along with improved rate capability and cycling stability,underlining its practical utility.These results suggest that the homologous interfacial coupling can boost the storage properties of nitrides,providing a valuable reference for improving the properties of electrodes with low theoretical capacities.
基金supported by the National Natural Science Foundation of China(Nos.22078118 and 42277219)the Natural Science Foundation of Guangdong Province,China(No.2023A1515010740).
文摘A novel photocatalytic cocatalyst, MoC quantum dots integrated into N-doped carbon microflowers (MoC–NC), was synthesized, establishing a key Mo–N interfacial bond. The Mo–N bond's regulation was achieved by adjusting the pH of Mo-polydopamine precursor solutions. A composite photocatalyst, MoC–NC/CdS (MNS), was formed by in situ growth of nano-CdS on MoC–NC. The pH during synthesis, crucial for Mo–N bond formation, significantly influenced Cr(Ⅵ) reduction and H_(2) evolution performance. The optimal MNS, created at pH 9.0, demonstrated 99.2% reduction efficiency for Cr(Ⅵ) in 20 min and H_(2) evolution rate of 11.4 mmol g^(-1) h^(-1) over 3 h, outperforming Pt/CdS. Mechanistic studies and density functional theory revealed MoC–NC's role in enhancing light absorption, reaction kinetics, and electron transport, attributing to its ultra-small quantum dots and abundant Mo–N bonds.
