Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this p...Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The catalyst prepared from H2PtCl6 with pH=3 shows greater catalytic performance than those prepared under other conditions.展开更多
An extensive study has been conducted on the proton exchange membrane fuel cells （PEMFCs） with reducing Pt loading. This is commonly achieved by developing methods to increase the utilization of the platinum in the ...An extensive study has been conducted on the proton exchange membrane fuel cells （PEMFCs） with reducing Pt loading. This is commonly achieved by developing methods to increase the utilization of the platinum in the catalyst layer of the electrodes. In this paper, a novel process of the catalyst layers was introduced and investigated. A mixture of carbon powder and Nafion solution was sprayed on the glassy carbon electrode （GCE） to form a thin carbon layer. Then Pt particles were deposited on the surface by reducing hexachloroplatinic （IV） acid hexahydrate with methanoic acid. SEM images showed a continuous Pt gradient profile among the thickness direction of the catalytic layer by the novel method. The Pt nanowires grown are in the size of 3 nm （diameter） x l0 nm （length） by high solution TEM image. The novel catalyst layer was characterized by cyclic voltammetry （CV） and scanning electron microscope （SEM） as compared with commercial Pt/C black and Pt catalyst layer obtained from sputtering. The results showed that the platinum nanoparticles deposited on the carbon powder were highly utilized as they directly faced the gas diffusion layer and offered easy access to reactants （oxygen or hydrogen）.展开更多
Colloidal synthesis method such as oleylamine(OAm)-stabilized process is of great interest for obtaining uniform and highly dispersed platinum nanoparticle catalysts, yet the ligand may unavoidably inhibit their elect...Colloidal synthesis method such as oleylamine(OAm)-stabilized process is of great interest for obtaining uniform and highly dispersed platinum nanoparticle catalysts, yet the ligand may unavoidably inhibit their electro-catalytic performance. Thus, fully removing these ligands is critical to activate catalyst surface. Previous research of OAm removal process pointed that thermal annealing was the most effective way in comparison with other methods such as chemical washing, UV–Ozone irradiation and cyclic voltammetry sweeping, but generally resulting in undesired growth of platinum nanoparticle. Few studies concerning a more efficient ligand removal process have been published yet. In this work we proposed a platinum in-situ catalytic OAm combustion strategy to elucidate the removal mechanism of OAm ligands in thermal process and the key experimental parameters were also optimized. In addition, heat flow signal based on differential scanning calorimetry(DSC) measurement as a sensitive indicator, is suggested to reveal the ligand removal efficiency, which is much more reliable than the traditional spectroscopy.In comparison with commercial Pt/C sample, such a surface clean Pt/C electrocatalyst has shown an enhanced specific activity for oxygen reduction reaction. Our removal strategy and the evaluation method are highly instructive to efficient removal of different organic ligands.展开更多
By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was ...By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was investigated.The results indicate that:(1) Hydrogen uptake is more quick and intense for decorated MWCNTs than that for not decorated ones at 10.931MPa and room temperature.The saturation of hydrogen uptake of the former only lasts about 30min,while the latter needs about 150 min;(2) The amount of hydrogen uptake of decorated MWCNTs is about 1.13wt%, which is larger than that of not decorated ones(about 0.54wt%);(3) However,more than 37% hydrogen absorbed by decorated MWCNTs is chemisorbed.展开更多
The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum c...The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.展开更多
The sintering of Pt nanoparticles is one of the main reasons for catalyst deactivation during the high-temperature propane dehydrogenation(PDH) reaction. Promoters and supports have been introduced to prolong the cata...The sintering of Pt nanoparticles is one of the main reasons for catalyst deactivation during the high-temperature propane dehydrogenation(PDH) reaction. Promoters and supports have been introduced to prolong the catalyst life.However, it is still necessary to develop novel catalysts with robust stability. Herein, the phosphorus-modified carbon nanotube-supported Pt nanoparticles were employed for the PDH process. Phosphorus modification improves the Pt dispersion, effectively promoting the activity of Pt/P-CNTs. Additionally, the phosphorus-modified CNTs can interact strongly with Pt nanoparticles by improving the electron transfer or hybridization, stabilizing Pt nanoparticles from agglomeration, and significantly enhancing the catalyst stability.展开更多
Carbon dioxide transformation to fuels or chemicals provides an attractive approach for its utilization as feedstock and its emission reduction. Herein, we report a gas-phase electrocatalytic reduction of CO2 in an el...Carbon dioxide transformation to fuels or chemicals provides an attractive approach for its utilization as feedstock and its emission reduction. Herein, we report a gas-phase electrocatalytic reduction of CO2 in an electrolytic cell, constructed using phosphoric acid-doped polybenz- imidazole （PBI） membrane, which allowed operation at 170 ℃ Pt/C and PtMo/C with variable ratio of Pt/Mo were studied as the cathode catalysts. The results showed that PtMo/C catalysts significantly enhanced CO formation and inhibited CH4 formation compared with Pt/C catalyst. Characterization by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy revealed that most Mo species existed as MoO3 in PtMo/C catalysts and the interaction between Pt and MoOx was likely responsible for the enhanced CO formation rate although these bicomponent catalysts in general had a larger particle size than Pt/C catalyst.展开更多
Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carb...Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.展开更多
制备了用于温和条件下催化氧化去除工业废气中高浓度甲醛(HCHO)的1%Pt-4%CeO2/AC催化剂.将高浓度甲醛的催化氧化过程与双甘膦氧化制备草甘膦的反应过程集成在一起,使草甘膦合成过程中产生和排放出来的甲醛(100–300 mg/m3)在通过催化剂...制备了用于温和条件下催化氧化去除工业废气中高浓度甲醛(HCHO)的1%Pt-4%CeO2/AC催化剂.将高浓度甲醛的催化氧化过程与双甘膦氧化制备草甘膦的反应过程集成在一起,使草甘膦合成过程中产生和排放出来的甲醛(100–300 mg/m3)在通过催化剂床层时被完全除去.系统研究了温度、空速和甲醛含量对甲醛去除率的影响.在气体空速(GHSV)低于20000 h 1时废气中几乎所有的甲醛都被氧化,处理后的废气中的甲醛含量低于0.1 mg/m3,甲醛的转化率为99.1%–100%.当GHSV为30000–50000 h 1,催化剂床层温度为12oC时,生产废气通过催化剂床层后的甲醛含量小于1.5 mg/m3,甲醛的转化率为97.56%–99.99%.1%Pt-4%CeO2/AC催化剂的中试试验结果表明,处理后最终尾气中甲醛含量小于10 mg/m3,有效地防止了甲醛对人们健康的危害,具有良好的产业化前景.展开更多
文摘Platinum/carbon catalyst is one of the most important catalysts in hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The preparation process and the supports of catalysts are studied in this paper. Raw materials and preparation procedure of the activated carbon have great influences on the compositions and surface structure of platinum/carbon catalysts. Platinum catalysts supported on activated carbon with high purity, high surface area, large pore volume and appropriate pore structure usually exhibit higher activities for hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichlorohydrazobenzene. The catalyst prepared from H2PtCl6 with pH=3 shows greater catalytic performance than those prepared under other conditions.
基金supported by the Royal Academy of Engineering,United Kingdom
文摘An extensive study has been conducted on the proton exchange membrane fuel cells （PEMFCs） with reducing Pt loading. This is commonly achieved by developing methods to increase the utilization of the platinum in the catalyst layer of the electrodes. In this paper, a novel process of the catalyst layers was introduced and investigated. A mixture of carbon powder and Nafion solution was sprayed on the glassy carbon electrode （GCE） to form a thin carbon layer. Then Pt particles were deposited on the surface by reducing hexachloroplatinic （IV） acid hexahydrate with methanoic acid. SEM images showed a continuous Pt gradient profile among the thickness direction of the catalytic layer by the novel method. The Pt nanowires grown are in the size of 3 nm （diameter） x l0 nm （length） by high solution TEM image. The novel catalyst layer was characterized by cyclic voltammetry （CV） and scanning electron microscope （SEM） as compared with commercial Pt/C black and Pt catalyst layer obtained from sputtering. The results showed that the platinum nanoparticles deposited on the carbon powder were highly utilized as they directly faced the gas diffusion layer and offered easy access to reactants （oxygen or hydrogen）.
基金the financial support by DICP Grant no.ZZBS201705。
文摘Colloidal synthesis method such as oleylamine(OAm)-stabilized process is of great interest for obtaining uniform and highly dispersed platinum nanoparticle catalysts, yet the ligand may unavoidably inhibit their electro-catalytic performance. Thus, fully removing these ligands is critical to activate catalyst surface. Previous research of OAm removal process pointed that thermal annealing was the most effective way in comparison with other methods such as chemical washing, UV–Ozone irradiation and cyclic voltammetry sweeping, but generally resulting in undesired growth of platinum nanoparticle. Few studies concerning a more efficient ligand removal process have been published yet. In this work we proposed a platinum in-situ catalytic OAm combustion strategy to elucidate the removal mechanism of OAm ligands in thermal process and the key experimental parameters were also optimized. In addition, heat flow signal based on differential scanning calorimetry(DSC) measurement as a sensitive indicator, is suggested to reveal the ligand removal efficiency, which is much more reliable than the traditional spectroscopy.In comparison with commercial Pt/C sample, such a surface clean Pt/C electrocatalyst has shown an enhanced specific activity for oxygen reduction reaction. Our removal strategy and the evaluation method are highly instructive to efficient removal of different organic ligands.
文摘By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was investigated.The results indicate that:(1) Hydrogen uptake is more quick and intense for decorated MWCNTs than that for not decorated ones at 10.931MPa and room temperature.The saturation of hydrogen uptake of the former only lasts about 30min,while the latter needs about 150 min;(2) The amount of hydrogen uptake of decorated MWCNTs is about 1.13wt%, which is larger than that of not decorated ones(about 0.54wt%);(3) However,more than 37% hydrogen absorbed by decorated MWCNTs is chemisorbed.
基金Supported by the National Key Research and Development Program of China(2017YFE0300302)the National Natural Science Foundation of China(21503199,21406212)Key Project of Applied&Basic Research of Sichuan Province(18YYJC1594)
文摘The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.
基金supported by the National Natural Science Foundation of China (Grant 21706036)the State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC)the Natural Science Foundation of Fujian Province (Grant 2018J05019)
文摘The sintering of Pt nanoparticles is one of the main reasons for catalyst deactivation during the high-temperature propane dehydrogenation(PDH) reaction. Promoters and supports have been introduced to prolong the catalyst life.However, it is still necessary to develop novel catalysts with robust stability. Herein, the phosphorus-modified carbon nanotube-supported Pt nanoparticles were employed for the PDH process. Phosphorus modification improves the Pt dispersion, effectively promoting the activity of Pt/P-CNTs. Additionally, the phosphorus-modified CNTs can interact strongly with Pt nanoparticles by improving the electron transfer or hybridization, stabilizing Pt nanoparticles from agglomeration, and significantly enhancing the catalyst stability.
基金supported by the Ministry of Science and Technology of China(Grant No:2012CB215500 and 2013CB933100)the National Natural Science Foundation of China(Grant No:21103178 and 21033009)
文摘Carbon dioxide transformation to fuels or chemicals provides an attractive approach for its utilization as feedstock and its emission reduction. Herein, we report a gas-phase electrocatalytic reduction of CO2 in an electrolytic cell, constructed using phosphoric acid-doped polybenz- imidazole （PBI） membrane, which allowed operation at 170 ℃ Pt/C and PtMo/C with variable ratio of Pt/Mo were studied as the cathode catalysts. The results showed that PtMo/C catalysts significantly enhanced CO formation and inhibited CH4 formation compared with Pt/C catalyst. Characterization by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy revealed that most Mo species existed as MoO3 in PtMo/C catalysts and the interaction between Pt and MoOx was likely responsible for the enhanced CO formation rate although these bicomponent catalysts in general had a larger particle size than Pt/C catalyst.
文摘Carbon nanotubes with diameters ranging between 140～220nm was synthesized with chemical vapor deposition method, and treated using nitric acid as oxidant. Pt/C catalysts were prepared using untreated and treated carbon nanotubes as supports, respectively. TEM and FT IR differential spectra showed that treated carbon nanotubes become short and possess more oxygen containing surface groups. The electrochemical studies indicated that the Pt/treated carbon nanotubes catalyst possessed much higher electrocatalytic activity for the oxidation of methanol than that of the Pt/untreated carbon nanotubes catalyst.
基金supported by the National Natural Science Foundation of China(21006073)the Shanghai Rising-Star Program(11QA1407200)+2 种基金the Shanghai Leading Academic Discipline Project(B303)the Open-Project Program of the State Key Laboratory of Chemical Engineering(SKL-ChE-08C07)the Program of Introducing Talents of Discipline to Universities(B08019)~~
文摘制备了用于温和条件下催化氧化去除工业废气中高浓度甲醛(HCHO)的1%Pt-4%CeO2/AC催化剂.将高浓度甲醛的催化氧化过程与双甘膦氧化制备草甘膦的反应过程集成在一起,使草甘膦合成过程中产生和排放出来的甲醛(100–300 mg/m3)在通过催化剂床层时被完全除去.系统研究了温度、空速和甲醛含量对甲醛去除率的影响.在气体空速(GHSV)低于20000 h 1时废气中几乎所有的甲醛都被氧化,处理后的废气中的甲醛含量低于0.1 mg/m3,甲醛的转化率为99.1%–100%.当GHSV为30000–50000 h 1,催化剂床层温度为12oC时,生产废气通过催化剂床层后的甲醛含量小于1.5 mg/m3,甲醛的转化率为97.56%–99.99%.1%Pt-4%CeO2/AC催化剂的中试试验结果表明,处理后最终尾气中甲醛含量小于10 mg/m3,有效地防止了甲醛对人们健康的危害,具有良好的产业化前景.
