Bimetallic metal organic framework(MOF)as a precursor to prepare catalysts with bifunctional catalytic activity of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)attracts more and more attention.Her...Bimetallic metal organic framework(MOF)as a precursor to prepare catalysts with bifunctional catalytic activity of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)attracts more and more attention.Herein,hollow oxygen deficiency-enriched NiFe_(2)O_(4) is synthesized by pyrolytic FeNi bimetallic MOF.The defects of rGO during carbonization can act as nucleation sites for FeNi particles.After nucleation and N doping,the FeNi particles were served as catalysts for the deposition of dissolved carbon in the defects of the N/rGO.These deposited carbon,like a bridge,connect N/rGO and hollow oxygen deficiency-enriched NiFe_(2)O_(4) together,which giving full play to the advantages of N/rGO in fast electron transfer,thereby improving its catalytic activity.The resultant NiFe_(2)O_(4)@N/rGO-800 exhibits a low overpotential of 252 mV at 20 mA cm^(-2) for OER and 157 mV at 10 mA cm^(-2) for HER in 1 M KOH,respectively.When used as bifunctional electrodes for overall water splitting,it also shows low cell voltage of 1.60 V and 1.67 V at 10 and 20 mA cm^(-2),respectively.展开更多
Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refract...Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(Ⅵ)and Rhodamine B(RhB)etc.Herein,we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide(rGO)porous nanosheet(S-CN/rGO PNs)via a supramolecular self-assembling followed by a solvothermal treatment.The as-prepared porous SCN/rGO PNs are stable with high specific surface area^188.5 m2 g-1 and exhibit a significantly enhanced photocatalytic activity of^17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(Ⅵ)under visible light irradiation,respectively.Typically,50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs.The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers.The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.展开更多
A series of Z-scheme TiO2/g-C3N4/RGO ternary heterojunction photocatalysts are successfully constructed via a direct electrospinning technique coupled with an annealing process for the first time. They are investigate...A series of Z-scheme TiO2/g-C3N4/RGO ternary heterojunction photocatalysts are successfully constructed via a direct electrospinning technique coupled with an annealing process for the first time. They are investigated comprehensively in terms of crystal structure, morphology, composition, specific surface area, photoelectrochemical properties, photodegradation performance, etc. Compared with binary TiO2/g-C3N4 and single-component photocatalysts, ternary heterojunction photocatalysts show the best photodegradation performance for RhB under stimulated sunlight. This can be attributed to the enlarged specific surface area (111.41 m2/g), the formation of Z-scheme heterojunction, and the high separation migration efficiency of photoexcited charge carriers. A potential Z-scheme mechanism for ternary heterojunction photocatalysts is proposed to elucidate the remarkably ameliorated photocatalytic performance based on active species trapping experiments, PL detection test of hydroxyl radicals, and photoelectrochemical properties.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21878231,21676202 and 51603145)Natural Science Foundation of Tianjin(Nos.19JCZDJC37300 and 17JCZDJC38100)supported by the Science and Technology Plans of Tianjin(Nos.17PTSYJC00040 and 18PTSYJC00180)。
文摘Bimetallic metal organic framework(MOF)as a precursor to prepare catalysts with bifunctional catalytic activity of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)attracts more and more attention.Herein,hollow oxygen deficiency-enriched NiFe_(2)O_(4) is synthesized by pyrolytic FeNi bimetallic MOF.The defects of rGO during carbonization can act as nucleation sites for FeNi particles.After nucleation and N doping,the FeNi particles were served as catalysts for the deposition of dissolved carbon in the defects of the N/rGO.These deposited carbon,like a bridge,connect N/rGO and hollow oxygen deficiency-enriched NiFe_(2)O_(4) together,which giving full play to the advantages of N/rGO in fast electron transfer,thereby improving its catalytic activity.The resultant NiFe_(2)O_(4)@N/rGO-800 exhibits a low overpotential of 252 mV at 20 mA cm^(-2) for OER and 157 mV at 10 mA cm^(-2) for HER in 1 M KOH,respectively.When used as bifunctional electrodes for overall water splitting,it also shows low cell voltage of 1.60 V and 1.67 V at 10 and 20 mA cm^(-2),respectively.
基金the Science and Technology Major Project of Shanxi Province(Grant Numbers MC2016-06)National Natural Science Foundation of China(21173041)the Opening Project of Jiangsu Key Laboratory of Advanced Metallic Materials,China.
文摘Graphitic carbon nitride(g-C3N4,CN)has attracted increasing interests in the field of photocatalysis due to its high visible-light-response.However,its photocatalytic activity is still lower for degradation of refractory contaminants such as Cr(Ⅵ)and Rhodamine B(RhB)etc.Herein,we report a facile method to synthesize a novel sulfur(S)-doped CN/reduced graphene oxide(rGO)porous nanosheet(S-CN/rGO PNs)via a supramolecular self-assembling followed by a solvothermal treatment.The as-prepared porous SCN/rGO PNs are stable with high specific surface area^188.5 m2 g-1 and exhibit a significantly enhanced photocatalytic activity of^17-fold and 15-fold higher than that of bulk CN for the degradation of RhB and Cr(Ⅵ)under visible light irradiation,respectively.Typically,50 mL of 15 mg/mL RhB can be degraded within 20 min by 10 mg S-CN/rGO PNs.The mechanism can be explained by the synergistic effect of S doping and porous structure which can effectively reduce the band gap of CN and increase the specific surface area to promote the separation and transfer of photo-generated charge carriers.The results have provided a new way to significantly enhance the photocatalytic activity of g-C3N4 for degradation of refractory contaminants.
基金supported by the Scientific Research Project from Hubei Provincial Department of Education(Q20181808)the Research and Innovation Initiatives of Wuhan Polytechnic University(2018J04,2018Y07)~~
文摘A series of Z-scheme TiO2/g-C3N4/RGO ternary heterojunction photocatalysts are successfully constructed via a direct electrospinning technique coupled with an annealing process for the first time. They are investigated comprehensively in terms of crystal structure, morphology, composition, specific surface area, photoelectrochemical properties, photodegradation performance, etc. Compared with binary TiO2/g-C3N4 and single-component photocatalysts, ternary heterojunction photocatalysts show the best photodegradation performance for RhB under stimulated sunlight. This can be attributed to the enlarged specific surface area (111.41 m2/g), the formation of Z-scheme heterojunction, and the high separation migration efficiency of photoexcited charge carriers. A potential Z-scheme mechanism for ternary heterojunction photocatalysts is proposed to elucidate the remarkably ameliorated photocatalytic performance based on active species trapping experiments, PL detection test of hydroxyl radicals, and photoelectrochemical properties.
