Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,...Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,we report a hybrid CO_(2)ER electrocatalyst composed of layered bismuth sulfide(Bi_(2)S_(3))and bismuth oxide(Bi_(2)O_(3))supported on carrageenan derived carbon(Bi-CDC)prepared by a combined pyrolysis with hydrothermal treatment.In such 3 D hybrid,layered Bi_(2)O_(3)and Bi_(2)S_(3)are uniformly grown on nanocarbon supports.Benefiting from strong synergistic effect between Bi_(2)O_(3)/Bi_(2)S_(3)and nanocarbon,Bi-CDC-1:2 displays a high Faradic efficiency(FE)of>80%for formate production in the range of-0.9 V to-1.1 V with the maximum formate FE of 85.6%and current density of 14.1 mA·cm^(-2) at-1.0 V.Further,a positive onset potential of-0.5 V,a low Tafel slope of 112.38 mV·dec^(-1),and a slight performance loss during long-term CO_(2)ER tests are observed on Bi-CDC-1:2.Experimental results shows that the better CO_(2)ER performance of Bi-CDC-1:2 than that of Bi_(2)O_(3)can be attributed to the strong interfacial interactions between nanocarbons and Bi_(2)O_(3)/Bi_(2)S_(3).In situ ATR-FTIR measurements reveal that the rate-determining step in the CO_(2)ER is the formation of HCOO^(*) intermediated.Compared with carbon support,Bi-CDC-1:2 can promote the production of HCOO^(*) intermediate and thus promoting CO_(2)ER kinetic.展开更多
通过连续离子层吸附法(SILAR)在TiO_(2)纳米管上负载Bi_(2)S_(3),通过XRD、SEM、XPS等手段对Bi_(2)S_(3)/TiO_(2)纳米复合材料的形貌、结构、元素组成和价态进行表征。同时在模拟太阳光条件下进行光电化学性能测试。Bi_(2)S_(3)改性后...通过连续离子层吸附法(SILAR)在TiO_(2)纳米管上负载Bi_(2)S_(3),通过XRD、SEM、XPS等手段对Bi_(2)S_(3)/TiO_(2)纳米复合材料的形貌、结构、元素组成和价态进行表征。同时在模拟太阳光条件下进行光电化学性能测试。Bi_(2)S_(3)改性后复合材料的带隙减小,光生载流子复合率大幅下降,当Bi_(2)S_(3)循环5次时,TiO_(2)纳米复合材料的光电化学性能最好。带隙减小到2.9 e V,光电流密度由改性前的200μA·cm^(-2)提升至550μA·cm^(-2),是改性前的2.75倍;将其与304不锈钢耦合后,电位降至-1.0 V,比改性前的耦合电位低80 m V,可以进一步提升对304不锈钢的光生阴极保护效果。展开更多
Photocatalytic ammonia generation via nitrogen reduction reaction(NRR)is a green and prospective nitrogen fixation technique.However,NRR is often hampered by the high N_(2) adsorption/activation energies and is accomp...Photocatalytic ammonia generation via nitrogen reduction reaction(NRR)is a green and prospective nitrogen fixation technique.However,NRR is often hampered by the high N_(2) adsorption/activation energies and is accompanied by a slow kinetics oxygen evolution reaction(OER).Herein,a robust Bi_(2)S_(3)/OVBi_(2)MoO_(6)S-scheme heterojunction is constructed using a simple in-situ anion exchange process,which enables oxygen vacancy(OVs)abundant Bi_(2)Mo O_(6) microspheres with surface deposited Bi_(2)S_(3).The asfabricated Bi_(2)S_(3)/OVBi_(2)MoO_(6) functioned as an effective photocatalyst to convert N_(2)-to-NH_(3) under mild conditions.The photocatalytic NH_(3)/NH_(4)^(+) production rate reached 126μmol g_(cat)^(-1)under visible light for2.5 h with 2%of Bi_(2)S_(3)/OVBi_(2)MoO_(6)photocatalyst,which was 8-fold higher than pristine Bi_(2)MoO_(6).Furthermore,the as-fabricated Bi_(2)S_(3)/Bi_(2)MoO_(6)heterojunction exhibited good selectivity,high stability and reproducibility.The excellent photocatalytic NRR performance was ascribed to the Bi_(2)S_(3)/Bi_(2)MoO_(6)heterojunction formed subsequent to the strong interaction between Bi_(2)S_(3)and Bi_(2)MoO_(6).The OVs facilitated the chemical adsorption process allowing activation of N_(2)molecule on the Bi_(2)S_(3)/Bi_(2)MoO_(6).Simultaneously,the S-scheme heterojunction prolonged the lifetime of photogenerated carriers,accelerated the electrons/holes spatial separation and accumulation on the Bi_(2)S_(3)(reduction)and Bi_(2)MoO_(6)side(oxidation),respectively,thus strengthening both OER and NRR half-reactions.This simple in-situ anion exchange method offers a novel technique for strengthening OER and NRR half-reactions in Bi-based photocatalysts for effective photocatalytic ammonia generation.展开更多
Highly competent and economical photocatalysts are one of the most charming targets in environmental restoration and clean production.Herein,a novel sulfur-vacancy-rich Bi/Bi_(2)S_(3)/SnS_(2)Z-scheme heterostruc-ture ...Highly competent and economical photocatalysts are one of the most charming targets in environmental restoration and clean production.Herein,a novel sulfur-vacancy-rich Bi/Bi_(2)S_(3)/SnS_(2)Z-scheme heterostruc-ture was constructed in situ and applied for the photoreduction Cr(VI)and nitrogen fixation.The fab-ricated Bi/Bi_(2)S_(3)/SnS_(2)-2 exhibits the optimum photoreduction Cr(VI)performance with the efficiency of 94.5%within 15 min visible light irradiation.The remarkably enhanced catalytic efficiency derived from the synergistic effect of the construction of intimate contacted interface,abundant sulfur vacancy and surface plasmon resonance(SPR)effect of metal Bi.Meanwhile,the excellent photocatalytic nitrogen fix-ation property(96.4μmol g^(-1)h^(-1))was achieved by Bi/Bi_(2)S_(3)/SnS_(2)-2 under full solar illumination because sulfur vacancy could provide sufficient catalytic sites to accelerate the adsorption and nitrogen activation.The Z-scheme heterostructure was proposed to expound the photocatalytic mechanism.This work offers a new perspective on hierarchical heterostructure with plentiful vacancies for environmental remediation and energy development.展开更多
基金supported by the National Natural Science Foundation of China(21922811,21878270,22178308,and 21961160742)Jiangxi Province“double thousand plan”project(205201000020)+4 种基金the Zhejiang Provincial Natural Science Foundation of China(LR19B060002)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2019R01006)Zhejiang Key Laboratory of Marine Materials and Protective Technologies(2020K10)Key Laboratory of Marine Materials and Related Technologies,CASthe Startup Foundation for Hundred-Talent Program of Zhejiang University。
文摘Electrochemical reduction of carbon dioxide(CO_(2)ER)into formate plays a crucial role in CO_(2)conversion and utilization.However,it still faces the problems of high overpotential and poor catalytic stability.Herein,we report a hybrid CO_(2)ER electrocatalyst composed of layered bismuth sulfide(Bi_(2)S_(3))and bismuth oxide(Bi_(2)O_(3))supported on carrageenan derived carbon(Bi-CDC)prepared by a combined pyrolysis with hydrothermal treatment.In such 3 D hybrid,layered Bi_(2)O_(3)and Bi_(2)S_(3)are uniformly grown on nanocarbon supports.Benefiting from strong synergistic effect between Bi_(2)O_(3)/Bi_(2)S_(3)and nanocarbon,Bi-CDC-1:2 displays a high Faradic efficiency(FE)of>80%for formate production in the range of-0.9 V to-1.1 V with the maximum formate FE of 85.6%and current density of 14.1 mA·cm^(-2) at-1.0 V.Further,a positive onset potential of-0.5 V,a low Tafel slope of 112.38 mV·dec^(-1),and a slight performance loss during long-term CO_(2)ER tests are observed on Bi-CDC-1:2.Experimental results shows that the better CO_(2)ER performance of Bi-CDC-1:2 than that of Bi_(2)O_(3)can be attributed to the strong interfacial interactions between nanocarbons and Bi_(2)O_(3)/Bi_(2)S_(3).In situ ATR-FTIR measurements reveal that the rate-determining step in the CO_(2)ER is the formation of HCOO^(*) intermediated.Compared with carbon support,Bi-CDC-1:2 can promote the production of HCOO^(*) intermediate and thus promoting CO_(2)ER kinetic.
文摘通过连续离子层吸附法(SILAR)在TiO_(2)纳米管上负载Bi_(2)S_(3),通过XRD、SEM、XPS等手段对Bi_(2)S_(3)/TiO_(2)纳米复合材料的形貌、结构、元素组成和价态进行表征。同时在模拟太阳光条件下进行光电化学性能测试。Bi_(2)S_(3)改性后复合材料的带隙减小,光生载流子复合率大幅下降,当Bi_(2)S_(3)循环5次时,TiO_(2)纳米复合材料的光电化学性能最好。带隙减小到2.9 e V,光电流密度由改性前的200μA·cm^(-2)提升至550μA·cm^(-2),是改性前的2.75倍;将其与304不锈钢耦合后,电位降至-1.0 V,比改性前的耦合电位低80 m V,可以进一步提升对304不锈钢的光生阴极保护效果。
基金financially supported by the National Natural Science Foundation of China(Nos.22168040,21666039,21663030)the Open Project of State Key Laboratory of Organic-Inorganic Composites Beijing Key Laboratory,Beijing University of Chemical Technology Beijing(No.oic-201901009)+3 种基金the Project of Science&Technology Office of Shaanxi Province(Nos.2018TSCXL-NY-02–01,2020JQ-791)the Project of Yan’an Science and Technology Bureau(No.2018KG-04)the Graduate Innovation Project of Yan’an University(No.YCX2020005)the Open Project of Chongqing Key Laboratory of Inorganic Special Functional Materials,Yangtze Normal University(No.KFKT202001)。
文摘Photocatalytic ammonia generation via nitrogen reduction reaction(NRR)is a green and prospective nitrogen fixation technique.However,NRR is often hampered by the high N_(2) adsorption/activation energies and is accompanied by a slow kinetics oxygen evolution reaction(OER).Herein,a robust Bi_(2)S_(3)/OVBi_(2)MoO_(6)S-scheme heterojunction is constructed using a simple in-situ anion exchange process,which enables oxygen vacancy(OVs)abundant Bi_(2)Mo O_(6) microspheres with surface deposited Bi_(2)S_(3).The asfabricated Bi_(2)S_(3)/OVBi_(2)MoO_(6) functioned as an effective photocatalyst to convert N_(2)-to-NH_(3) under mild conditions.The photocatalytic NH_(3)/NH_(4)^(+) production rate reached 126μmol g_(cat)^(-1)under visible light for2.5 h with 2%of Bi_(2)S_(3)/OVBi_(2)MoO_(6)photocatalyst,which was 8-fold higher than pristine Bi_(2)MoO_(6).Furthermore,the as-fabricated Bi_(2)S_(3)/Bi_(2)MoO_(6)heterojunction exhibited good selectivity,high stability and reproducibility.The excellent photocatalytic NRR performance was ascribed to the Bi_(2)S_(3)/Bi_(2)MoO_(6)heterojunction formed subsequent to the strong interaction between Bi_(2)S_(3)and Bi_(2)MoO_(6).The OVs facilitated the chemical adsorption process allowing activation of N_(2)molecule on the Bi_(2)S_(3)/Bi_(2)MoO_(6).Simultaneously,the S-scheme heterojunction prolonged the lifetime of photogenerated carriers,accelerated the electrons/holes spatial separation and accumulation on the Bi_(2)S_(3)(reduction)and Bi_(2)MoO_(6)side(oxidation),respectively,thus strengthening both OER and NRR half-reactions.This simple in-situ anion exchange method offers a novel technique for strengthening OER and NRR half-reactions in Bi-based photocatalysts for effective photocatalytic ammonia generation.
基金supported by the National Natural Science Foun-dation of China(Nos.22178038 and 21878031)Innovation Supporting Plan for High-level Talents of Dalian(No.2021RQ116).
文摘Highly competent and economical photocatalysts are one of the most charming targets in environmental restoration and clean production.Herein,a novel sulfur-vacancy-rich Bi/Bi_(2)S_(3)/SnS_(2)Z-scheme heterostruc-ture was constructed in situ and applied for the photoreduction Cr(VI)and nitrogen fixation.The fab-ricated Bi/Bi_(2)S_(3)/SnS_(2)-2 exhibits the optimum photoreduction Cr(VI)performance with the efficiency of 94.5%within 15 min visible light irradiation.The remarkably enhanced catalytic efficiency derived from the synergistic effect of the construction of intimate contacted interface,abundant sulfur vacancy and surface plasmon resonance(SPR)effect of metal Bi.Meanwhile,the excellent photocatalytic nitrogen fix-ation property(96.4μmol g^(-1)h^(-1))was achieved by Bi/Bi_(2)S_(3)/SnS_(2)-2 under full solar illumination because sulfur vacancy could provide sufficient catalytic sites to accelerate the adsorption and nitrogen activation.The Z-scheme heterostructure was proposed to expound the photocatalytic mechanism.This work offers a new perspective on hierarchical heterostructure with plentiful vacancies for environmental remediation and energy development.
