Heterojunction engineering is considered as one of the most effective methods to improve the hydrogen production performance of photocatalysts.In this study,a green,simple and gentle method was used to deposit tiny Ni...Heterojunction engineering is considered as one of the most effective methods to improve the hydrogen production performance of photocatalysts.In this study,a green,simple and gentle method was used to deposit tiny Ni S onto CTF-ES_(200)under xenon lamp irradiation to form heterostructures.The experimental results show that the hydrogen production rate of the synthesized Ni S/CTF-ES_(200)is as high as 22.98mmol g^(-1)h^(-1),showing a higher photocatalytic hydrogen production rate compared to other Ni S-loaded nonmetallic semiconductor materials,which is also much higher than that of pure CTF-ES_(200).The interface electric field(IEF)in this p-n heterojunction leads to an accumulation of photoelectrons on the conduction band of CTF-ES_(200),which makes CTF-ES_(200)to keep a high reductiveness for the hydrogen evolution reaction(HER),and significantly improve the separation efficiency of photoelectrons and holes.Furthermore,XPS and EXAFS data show that an efficient electron transport channel is constructed through the formation of Ni-N bond,which further accelerates the interface carrier transport efficiency.This study provides an effective idea for the preparation of highly efficient heterojunction photocatalysts.展开更多
To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrot...To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrothermal loading.The decorated NiS exhibits particle(NiS@PAN-NiS)and needle-like(NiS@PAN-NiS^(*))morphologies.After adding the catalysts into MgH_(2),the synthesized MgH_(2)-5 wt%NiS@PAN-NiS composite can absorb 2.6 wt%hydrogen at 353 K and release 5.0 wt%hydrogen within 1 h at 573 K.The initial hydrogen desorption temperature was reduced to 539 K.The activation energies for hydrogen absorption/desorption were greatly reduced to 66.76 and 89.95 kJ mol^(-1),respectively.The method of confining by electrospinning and particle decoration by hydrothermal loading reduce NiS particle agglomeration.The Mg_(2)Ni/Mg_(2)NiH_(4)hydrogen pump formed by reaction between NiS and MgH_(2)effectively enhanced hydrogen absorption and desorption kinetics.The formed MgS also improved the catalytic activity on the transformation of Mg and MgH_(2).Moreover,the carbon fibers should influence the contact between in situ formed MgS and Mg_(2)Ni,providing more catalytic sites and hydrogen diffusion pathways.The construction of NiS/carbon fibers confined NiS composite by carbon fibers derived from pyrolyzation as medium provides considerable way for designing NiS-based catalysts to enhance the hydrogen storage performances of MgH_(2).展开更多
Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is ...Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.展开更多
Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granula...Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granular surface,where large particles were covered with nanoscale clusters.Additionally,C atoms primarily existed within the coatings as a solid solution,maintaining the FCC structures.Compared to binary Ni−Co coatings,the Ni−Co−C alloy coatings exhibited significantly improved hardness,wear resistance,and adhesion strength,which could be attributed to the potential strengthening effect of the C atoms.Specifically,the introduction of C atoms optimized the local charge density and electron distribution in the alloy,transforming local weak ionic bonds into strong covalent interactions,thereby enhancing the bonding capability between the corresponding atoms in the NiCo bulk.展开更多
NiS2 is a promising cocatalyst to improve the photocatalytic performance of g-C3N4 for the production of H2.However,the synthesis of the NiS2 cocatalyst usually requires harsh conditions,which risks destroying the mic...NiS2 is a promising cocatalyst to improve the photocatalytic performance of g-C3N4 for the production of H2.However,the synthesis of the NiS2 cocatalyst usually requires harsh conditions,which risks destroying the microstructures of the g-C3N4 photocatalysts.In this study,a facile and low-temperature（80 ℃） impregnation method was developed to prepare NiS2/g-C3N4 photocatalysts.First,the g-C3N4 powders were processed by the hydrothermal method in order to introduce oxygen-containing functional groups（such as-OH and-C0NH-） to the surface of g-C3N4.Then,the Ni^2＋ ions could be adsorbed near the g-C3N4 via strong electrostatic interaction between g-C3N4 and Ni^2＋ ions upon the addition of Ni（NO3）2 solution.Finally,NiS2 nanoparticles were formed on the surface of g-C3N4 upon the addition of TAA.It was found that the NiS2 nanoparticles were solidly and homogeneously grafted on the surface of g-C3N4,resulting in greatly improved photocatalytic H2production.When the amount of NiS2 was 3 wt%,the resultant NiS2/g-C3N4 photocatalyst showed the highest H2 evolution rate（116.343 μmol h^-1 g^-1）,which is significantly higher than that of the pure g-C3N4（3 μmol h^-1 g^-1）.Moreover,the results of a recycling test for the NiS2/g-C3N4（3 wt%）sample showed that this sample could maintain a stable and effective photocatalytic H2-evolution performance under visible-light irradiation.Based on the above results,a possible mechanism of the improved photocatalytic performance was proposed for the presented NiS2/g-C3N4 photocatalysts,in which the photogenerated electrons of g-C3N4 can be rapidly transferred to the NiS2 nanoparticles via the close and continuous contact between them;then,the photogenerated electrons rapidly react with H2O adsorbed on the surface of NiS2,which has a surficial metallic character and high catalytic activity,to produce H2.Considering the mild and facile synthesis method,the presented low-cost and highly efficient NiS2-modified g-C3N4 photocatalysts would have great potential for practical use in photocatalytic H2 production.展开更多
NiS Nanoparticles were synthesized from nickel hexadecylxanthate single-source precursor via a thermolytic method. The partial xanthate ligand dissociated from precursor absorbed to the surface of NiS nanoparticles as...NiS Nanoparticles were synthesized from nickel hexadecylxanthate single-source precursor via a thermolytic method. The partial xanthate ligand dissociated from precursor absorbed to the surface of NiS nanoparticles as capping agent. The products were characterized by FTIR,XRD and TEM. The results indicate that NiS nanoparticles have excellent dispersibility with hexagonal structure and the average diameter is 15 nm.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22271022)the Science and Technology Development Planning of Jilin Province(No.YDZJ202201ZYTS342)supported by the China Scholarship Council(CSC,No.201802335014)。
文摘Heterojunction engineering is considered as one of the most effective methods to improve the hydrogen production performance of photocatalysts.In this study,a green,simple and gentle method was used to deposit tiny Ni S onto CTF-ES_(200)under xenon lamp irradiation to form heterostructures.The experimental results show that the hydrogen production rate of the synthesized Ni S/CTF-ES_(200)is as high as 22.98mmol g^(-1)h^(-1),showing a higher photocatalytic hydrogen production rate compared to other Ni S-loaded nonmetallic semiconductor materials,which is also much higher than that of pure CTF-ES_(200).The interface electric field(IEF)in this p-n heterojunction leads to an accumulation of photoelectrons on the conduction band of CTF-ES_(200),which makes CTF-ES_(200)to keep a high reductiveness for the hydrogen evolution reaction(HER),and significantly improve the separation efficiency of photoelectrons and holes.Furthermore,XPS and EXAFS data show that an efficient electron transport channel is constructed through the formation of Ni-N bond,which further accelerates the interface carrier transport efficiency.This study provides an effective idea for the preparation of highly efficient heterojunction photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52101274 and 52472131)the Natural Science Foundation of Shandong Province(Nos.ZR2020QE011 and ZR2022ME089)+6 种基金Yantai Basic Research Project(No.2024JCYJ097)the Key Research and Development Projects of Shandong Province(No.2024TSGC0402)the Youth Top Talent Foundation of Yantai University(No.2219008)the Graduate Innovation Foundation of Yantai University(No.GIFYTU2240)the Natural Science Foundation of Qinghai Province for Distinguished Young Scholars(No.2025-ZJ-966J)the Talent Youth Project of Chinese Academy of Sciences(No.E410GC03)the CollegeStudent Innovation and Entrepreneurship Training Program Project(No.202311066088)
文摘To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrothermal loading.The decorated NiS exhibits particle(NiS@PAN-NiS)and needle-like(NiS@PAN-NiS^(*))morphologies.After adding the catalysts into MgH_(2),the synthesized MgH_(2)-5 wt%NiS@PAN-NiS composite can absorb 2.6 wt%hydrogen at 353 K and release 5.0 wt%hydrogen within 1 h at 573 K.The initial hydrogen desorption temperature was reduced to 539 K.The activation energies for hydrogen absorption/desorption were greatly reduced to 66.76 and 89.95 kJ mol^(-1),respectively.The method of confining by electrospinning and particle decoration by hydrothermal loading reduce NiS particle agglomeration.The Mg_(2)Ni/Mg_(2)NiH_(4)hydrogen pump formed by reaction between NiS and MgH_(2)effectively enhanced hydrogen absorption and desorption kinetics.The formed MgS also improved the catalytic activity on the transformation of Mg and MgH_(2).Moreover,the carbon fibers should influence the contact between in situ formed MgS and Mg_(2)Ni,providing more catalytic sites and hydrogen diffusion pathways.The construction of NiS/carbon fibers confined NiS composite by carbon fibers derived from pyrolyzation as medium provides considerable way for designing NiS-based catalysts to enhance the hydrogen storage performances of MgH_(2).
文摘Hydrogen peroxide(H_(2)O_(2)),an environmentally friendly chemical with high value,is extensively used in industrial production and daily life.However,the traditional anthraquinone method for H_(2)O_(2) production is associated with a highly energy-consuming and heavily polluting process.Solor-driven photocatalytic evolution of H_(2)O_(2) is a promising,eco-friendly,and energy-efficient strategy that holds great potential to substitute the traditional approach.Here,a ternary photocatalyst,NiS/CdS/Halloysite nanotubes(NiS/CdS/HNTs)is designed and prepared with an earth-abundant clay mineral HNTs as the support and NiS as a co-catalyst.The pivotal roles of HNTs and NiS in the photocatalytic process are elucidated by experiments and theoretical calculations.HNTs serve as the carrier,which allows CdS to be uniformly dispersed onto its surface as small particles,increasing effective contact with H_(2)O and O_(2) for H_(2)O_(2) formation.Simultaneously,it resulted in the formation of a Schottky junction between NiS and CdS,which not only favors photogenerated charges separating efficiently but also provides a unidirectional path to transfer electrons.Consequently,the optimized NiS/CdS/HNTs composite demonstrates an H_(2)O_(2) evolution rate of 380.5μmol·g^(-1)·h^(-1) without adding any sacrificial agent or extra O_(2),nearly 5.0 times that of pure CdS.This work suggests a feasible idea for designing and developing highly active and low-cost solar energy catalytic composite materials.
基金supported by the National Natural Science Foundation of China(Nos.52274320,52074053)。
文摘Ni−Co−C alloy coatings with exceptional properties were fabricated via electrodeposition using an ammonium oxalate−ammonium citrate system.The optimized coatings exhibited dense crystallization with a distinct granular surface,where large particles were covered with nanoscale clusters.Additionally,C atoms primarily existed within the coatings as a solid solution,maintaining the FCC structures.Compared to binary Ni−Co coatings,the Ni−Co−C alloy coatings exhibited significantly improved hardness,wear resistance,and adhesion strength,which could be attributed to the potential strengthening effect of the C atoms.Specifically,the introduction of C atoms optimized the local charge density and electron distribution in the alloy,transforming local weak ionic bonds into strong covalent interactions,thereby enhancing the bonding capability between the corresponding atoms in the NiCo bulk.
基金supported by the National Natural Science Foundation of China (21277107, 21477094, 51672203, 51472192)the Program for New Century Excellent Talents in University (NCET-13-0944)the Fundamental Research Funds for the Central Universities (WUT 2015IB002)~~
文摘NiS2 is a promising cocatalyst to improve the photocatalytic performance of g-C3N4 for the production of H2.However,the synthesis of the NiS2 cocatalyst usually requires harsh conditions,which risks destroying the microstructures of the g-C3N4 photocatalysts.In this study,a facile and low-temperature（80 ℃） impregnation method was developed to prepare NiS2/g-C3N4 photocatalysts.First,the g-C3N4 powders were processed by the hydrothermal method in order to introduce oxygen-containing functional groups（such as-OH and-C0NH-） to the surface of g-C3N4.Then,the Ni^2＋ ions could be adsorbed near the g-C3N4 via strong electrostatic interaction between g-C3N4 and Ni^2＋ ions upon the addition of Ni（NO3）2 solution.Finally,NiS2 nanoparticles were formed on the surface of g-C3N4 upon the addition of TAA.It was found that the NiS2 nanoparticles were solidly and homogeneously grafted on the surface of g-C3N4,resulting in greatly improved photocatalytic H2production.When the amount of NiS2 was 3 wt%,the resultant NiS2/g-C3N4 photocatalyst showed the highest H2 evolution rate（116.343 μmol h^-1 g^-1）,which is significantly higher than that of the pure g-C3N4（3 μmol h^-1 g^-1）.Moreover,the results of a recycling test for the NiS2/g-C3N4（3 wt%）sample showed that this sample could maintain a stable and effective photocatalytic H2-evolution performance under visible-light irradiation.Based on the above results,a possible mechanism of the improved photocatalytic performance was proposed for the presented NiS2/g-C3N4 photocatalysts,in which the photogenerated electrons of g-C3N4 can be rapidly transferred to the NiS2 nanoparticles via the close and continuous contact between them;then,the photogenerated electrons rapidly react with H2O adsorbed on the surface of NiS2,which has a surficial metallic character and high catalytic activity,to produce H2.Considering the mild and facile synthesis method,the presented low-cost and highly efficient NiS2-modified g-C3N4 photocatalysts would have great potential for practical use in photocatalytic H2 production.
文摘NiS Nanoparticles were synthesized from nickel hexadecylxanthate single-source precursor via a thermolytic method. The partial xanthate ligand dissociated from precursor absorbed to the surface of NiS nanoparticles as capping agent. The products were characterized by FTIR,XRD and TEM. The results indicate that NiS nanoparticles have excellent dispersibility with hexagonal structure and the average diameter is 15 nm.
