以蔗糖作为表面活性剂,采用水热法成功制备出可见光响应的线团状C/BiOCl复合光催化剂。对所制备样品进行一系列表征。结果表明:所制备样品显著吸收可见光;添加0.3 g蔗糖制备的样品呈线团状分级结构,且具有最好的可见光催化活性,200 min ...以蔗糖作为表面活性剂,采用水热法成功制备出可见光响应的线团状C/BiOCl复合光催化剂。对所制备样品进行一系列表征。结果表明:所制备样品显著吸收可见光;添加0.3 g蔗糖制备的样品呈线团状分级结构,且具有最好的可见光催化活性,200 min RhB降解率约为50%。自由基抑制实验发现:光催化降解RhB过程中主要的活性物种为·OH和·O^(2-)。循环实验发现样品具有良好的循环稳定性。展开更多
通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其...通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其的降解率在1 h可达到81.44%,催化效率达64.15%,其动力学过程符合一级动力学模型。展开更多
The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving ...The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials.展开更多
Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effec...Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.展开更多
The use of functional materials such as carbon-bismuth oxyhalides in integrated photorefineries for the clean production of fine chemicals requires restructuring.A facile biomass-assisted solvothermal fabrication of c...The use of functional materials such as carbon-bismuth oxyhalides in integrated photorefineries for the clean production of fine chemicals requires restructuring.A facile biomass-assisted solvothermal fabrication of carbon/bismuth oxychloride nanocomposites(C/BiOCl)was achieved at various temperatures.Compared with BiOCl and C/BiOCl-120,C/BiOCl-180 exhibited higher crystallinity,wider visible light absorption,and a faster migration/separation rate of photoinduced carriers.For the selective C–C bond cleavage of biomass-based feedstocks photocatalyzed by C/BiOCl-180,the xylose conversion and lactic acid yield were 100%and 92.5%,respectively.C/BiOCl-180 efficiently converted different biomass-based monosaccharides to lactic acid,and the efficiency of pentoses was higher than that of hexoses.Moreover,lactic acid synthesis was favored by all active radicals including superoxide ion(·O_(2)^(−)),holes(h^(+)),hydroxyl radical(·OH),and singlet oxygen(^(1)O_(2)),with·O_(2)^(−)playing a key role.The fabricated photocatalyst was stable,economical,and recyclable.The use of biomass-derived monosaccharides for the clean production of lactic acid via the C/BiOCl-180 photocatalyst has opened new research horizons for the investigation and application of C–C bond cleavage in biomass-based feedstocks.展开更多
文摘以蔗糖作为表面活性剂,采用水热法成功制备出可见光响应的线团状C/BiOCl复合光催化剂。对所制备样品进行一系列表征。结果表明:所制备样品显著吸收可见光;添加0.3 g蔗糖制备的样品呈线团状分级结构,且具有最好的可见光催化活性,200 min RhB降解率约为50%。自由基抑制实验发现:光催化降解RhB过程中主要的活性物种为·OH和·O^(2-)。循环实验发现样品具有良好的循环稳定性。
文摘通过溶剂热法制备了球状C-TiO_(2)催化剂以及BiOCl/C-TiO_(2)复合光催化材料。与纯TiO_(2)相比,球状C-TiO_(2)和BiOCl/C-TiO_(2)的禁带宽度显著降低。以亚甲基蓝为降解目标,当染料质量浓度为25 mg/L、pH为7时,0.1 g BiOCl/CTiO_(2)对其的降解率在1 h可达到81.44%,催化效率达64.15%,其动力学过程符合一级动力学模型。
文摘The simultaneous integration of heteroatom doping and surface plasmon resonance(SPR) modulation on semiconductor photocatalysts could be capable of improving visible light utilization and charge separation, achieving better solar light conversion and photocatalysis efficiency. For this purpose, we have designed a novel Bi quantum dots(QDs) implanted C-doped BiOCl photocatalyst(C/BOC/B) for NOx removal. The feasibility was firstly evaluated through density functional theory(DFT) calculations methods, which indicates that the enhanced photocatalytic performance could be expected owing to the synergistic effects of doped C heteroatoms and loaded Bi QDs. Then, the C/BOC/B was synthesized via a facile hydrothermal method and exhibited efficient and stable visible light photocatalytic NO removal. The results found that the doped C atoms can serve as electron guides to induce oriented charge transfer from Bi QDs to BiOCl, while the Bi QDs can act as light-capture and electron-donating sites. The reaction pathway and mechanism for NO conversion was unveiled by in situ Fourier-transform infrared spectroscopy combined with DFT calculation. The enhanced adsorption of reactants and intermediates could promote the overall reaction efficiency and selectivity in photocatalytic NO conversion. This work could provide a new perspective on the mechanistic understanding of the synergistic effects toward non-metal doping and SPR effects in semiconductor photocatalysts, and this presented technique could be extended for other semiconductor materials.
基金This project was supported by the China Postdoctoral Science Foundation,Henan Postdoctoral Science Foundation,NCWU 2017 Annual Teaching Teacher Training Object ProjectKey Research Projects of Higher Education in Henan Province(18B150010)+1 种基金the Key Scientific Research Project of Henan Higher Education(No.17A520011)the Science and Technology Research Project of Henan Province(182102110029)
文摘Impurity formation energy, electronic structure, and photocatalytic properties of C-, N-, or S-doped BiOCl are investigated by density-functional theory plus U calculations(DFT + U). Results show that the doping effect of S is better than that of C or N on the tunable photocatalytic activities of BiOCl. At low concentration, S-doped BiOCl systems are the most stable under Bi-rich growth conditions because of their lower impurity-formation energy. Compared with the electronic structures of S-doped BiOCl, C-or N-doped BiOCl have relatively deeper impurity energy levels appearing in their band gap(except Bi_(36)O_(35)NCl_(36)), which may act as photogenerated carrier-recombination centers and reduce photocatalytic activity. At high concentration, S is substituted on the O lattice site system, whereas some S 3p states mix with the valence band; this mixture leads to an obvious band-gap decrease and continuum-state formation above the valence-band edge of BiOCl. Such activity is advantageous to photochemical catalysis response. Compared with pure Bi OCl and a low-concentration S-doped system, a high-concentration S-doped system shows an obvious redshift on the absorption edge and has better photocatalytic O_2 evolution performance.
基金supported by the Foundation of the NSFC-CONICFT Joint Project(Grant No.51961125207)National Natural Science Foundation of China(Grant No.22008018)+1 种基金Innovation Support Program for High-level Talents of Dalian(Top and Leading Talents)(Grant No.201913)Dalian City Outstanding Talent Project(Grant No.2019RD13).
文摘The use of functional materials such as carbon-bismuth oxyhalides in integrated photorefineries for the clean production of fine chemicals requires restructuring.A facile biomass-assisted solvothermal fabrication of carbon/bismuth oxychloride nanocomposites(C/BiOCl)was achieved at various temperatures.Compared with BiOCl and C/BiOCl-120,C/BiOCl-180 exhibited higher crystallinity,wider visible light absorption,and a faster migration/separation rate of photoinduced carriers.For the selective C–C bond cleavage of biomass-based feedstocks photocatalyzed by C/BiOCl-180,the xylose conversion and lactic acid yield were 100%and 92.5%,respectively.C/BiOCl-180 efficiently converted different biomass-based monosaccharides to lactic acid,and the efficiency of pentoses was higher than that of hexoses.Moreover,lactic acid synthesis was favored by all active radicals including superoxide ion(·O_(2)^(−)),holes(h^(+)),hydroxyl radical(·OH),and singlet oxygen(^(1)O_(2)),with·O_(2)^(−)playing a key role.The fabricated photocatalyst was stable,economical,and recyclable.The use of biomass-derived monosaccharides for the clean production of lactic acid via the C/BiOCl-180 photocatalyst has opened new research horizons for the investigation and application of C–C bond cleavage in biomass-based feedstocks.
