Abstract: In the occurrence of arc discharges, spark discharges, corona discharges and overheated faults in electrical equipment, SF 6would be decomposed to complicated byproducts, such as SO2 , H2S and HF. Analyzing ...Abstract: In the occurrence of arc discharges, spark discharges, corona discharges and overheated faults in electrical equipment, SF 6would be decomposed to complicated byproducts, such as SO2 , H2S and HF. Analyzing these byproducts is an effective method to judge the internal operation condition of electric equipment. In order to study characters of SF6byproducts at different temperature of overheated faults in the electric equipment, a series of overheated faults of electric equipment were simulated. SF6is very stable and not significantly decomposed at 200oC, 250oC and 300oC. SF6is significantly decomposed to SO2, H2S and HF at 350oC. The concentration of SO2, H2S and HF was 7.2, 1.6 and 1.9 μL/L after heating for 5 hours in environment of SF6with 3616 μL/L water, and it was increased to 23.0, 3.0 and 1.2 μL/L 3 hours later. SF6is more easily to be decomposed and decomposed more rapidly at higher temperature. The concentration of SO2, H2S and HF was 62.2, 15.6 and 3.6 μL/L after heating for 5 hours in environment of SF6with 4064 μL/L water, and it was increased to 91.4, 25.2 and 2.3 μL/L 3 hours later. SF6will be decomposed to format HF, which is strongly corrosive and whose concentration is likely to decrease when it is above a certain concentration.展开更多
Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the ...Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the pre-formed Au/g-C_3N_4 for photocatalytic hydrogen evolution. Their structure, morphology and optical property were investigated in detail. Photocatalytic activities of the developed photocatalysts for water splitting were evaluated under visible-light irradiation(k > 420 nm) using glucose as electron donor.The highest hydrogen evolution rate of 123 lmol g^(-1)h^(-1)is achieved by Cd_(0.8Z)n_(0.2)S/Au/g-C_3N_4, which is 52.2 and 8.63 times higher than that of Au/g-C_3N_4 and Cd S/Au/g-C_3N_4, respectively. The results of photoluminescence spectra, photoelectrochemical and time-resolved photoluminescence spectra indicate that the improved photocatalytic activities for Cd_xZn_(1-x)S/Au/g-C_3N_4 are due to the efficient separation of photogenerated carriers. In addition, it is noteworthy that the undesired byproducts CO and CO_2 are greatly reduced by introducing CdxZn_(1-x)S over Au/g-C_3N_4 surface. In the photocatalytic process, gluconic acid originated from the reaction of photogenerated hydroxyl radical with glucose plays a vital role on suppressing the formation of the gas byproducts. The present work will provide a new strategy to design Z-scheme photocatalysts with enhanced efficiency for water splitting along with suppressing the byproducts.展开更多
文摘Abstract: In the occurrence of arc discharges, spark discharges, corona discharges and overheated faults in electrical equipment, SF 6would be decomposed to complicated byproducts, such as SO2 , H2S and HF. Analyzing these byproducts is an effective method to judge the internal operation condition of electric equipment. In order to study characters of SF6byproducts at different temperature of overheated faults in the electric equipment, a series of overheated faults of electric equipment were simulated. SF6is very stable and not significantly decomposed at 200oC, 250oC and 300oC. SF6is significantly decomposed to SO2, H2S and HF at 350oC. The concentration of SO2, H2S and HF was 7.2, 1.6 and 1.9 μL/L after heating for 5 hours in environment of SF6with 3616 μL/L water, and it was increased to 23.0, 3.0 and 1.2 μL/L 3 hours later. SF6is more easily to be decomposed and decomposed more rapidly at higher temperature. The concentration of SO2, H2S and HF was 62.2, 15.6 and 3.6 μL/L after heating for 5 hours in environment of SF6with 4064 μL/L water, and it was increased to 91.4, 25.2 and 2.3 μL/L 3 hours later. SF6will be decomposed to format HF, which is strongly corrosive and whose concentration is likely to decrease when it is above a certain concentration.
基金supported by the National Natural Science Foundation of China (U1403193 and 21643012)the ‘‘Western Light” Program (YB201303)the Outstanding Young Scientist Program of Chinese Academy of Sciences
文摘Inspired by natural photosynthesis, a new series of Z-scheme Cd_xZn_(1-x)S/Au/g-C_3N_4 photocatalysts were synthesized via depositing Au particles on g-C_3N_4, followed by anchoring CdxZn_(1-x)S solid solution on the pre-formed Au/g-C_3N_4 for photocatalytic hydrogen evolution. Their structure, morphology and optical property were investigated in detail. Photocatalytic activities of the developed photocatalysts for water splitting were evaluated under visible-light irradiation(k > 420 nm) using glucose as electron donor.The highest hydrogen evolution rate of 123 lmol g^(-1)h^(-1)is achieved by Cd_(0.8Z)n_(0.2)S/Au/g-C_3N_4, which is 52.2 and 8.63 times higher than that of Au/g-C_3N_4 and Cd S/Au/g-C_3N_4, respectively. The results of photoluminescence spectra, photoelectrochemical and time-resolved photoluminescence spectra indicate that the improved photocatalytic activities for Cd_xZn_(1-x)S/Au/g-C_3N_4 are due to the efficient separation of photogenerated carriers. In addition, it is noteworthy that the undesired byproducts CO and CO_2 are greatly reduced by introducing CdxZn_(1-x)S over Au/g-C_3N_4 surface. In the photocatalytic process, gluconic acid originated from the reaction of photogenerated hydroxyl radical with glucose plays a vital role on suppressing the formation of the gas byproducts. The present work will provide a new strategy to design Z-scheme photocatalysts with enhanced efficiency for water splitting along with suppressing the byproducts.
