In the preparation of a series of Ce_(0.8)Zr_(0.2)O_(y)catalysts catalyzing the removal of formaldehyde,BET,H2-TPR,IR,SEM,XPS,and XRD were used to characterize the catalyst,and the influence of humidity on the catalys...In the preparation of a series of Ce_(0.8)Zr_(0.2)O_(y)catalysts catalyzing the removal of formaldehyde,BET,H2-TPR,IR,SEM,XPS,and XRD were used to characterize the catalyst,and the influence of humidity on the catalyst activity was studied by adjusting the humidity during the process.The experimental results showed that the formaldehyde removal rate increased with the increase of humidity.When the humidity was higher than 50%,the formaldehyde removal rate decreased by 3%over that when the humidity was 50%.The characterization results showed that humidity facilitated the activation of oxygen and the formation of hydroxyl groups,which both promoted the formation and oxidative decomposition of intermediates and prevented the deposition of intermediates that clogged the pores,allowing more formaldehyde to be adsorbed and oxidized,which increased the activity of the catalyst.This provides new mechanistic evidence for the oxidation of formaldehyde and helps in the development of relatively low-cost materials for formaldehyde purification.展开更多
High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface...High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.展开更多
基金Funded by the Young and Middle-aged Academic and Technical Leaders Reserve Talent Project of Yunnan Province(No.202105AC160054)。
文摘In the preparation of a series of Ce_(0.8)Zr_(0.2)O_(y)catalysts catalyzing the removal of formaldehyde,BET,H2-TPR,IR,SEM,XPS,and XRD were used to characterize the catalyst,and the influence of humidity on the catalyst activity was studied by adjusting the humidity during the process.The experimental results showed that the formaldehyde removal rate increased with the increase of humidity.When the humidity was higher than 50%,the formaldehyde removal rate decreased by 3%over that when the humidity was 50%.The characterization results showed that humidity facilitated the activation of oxygen and the formation of hydroxyl groups,which both promoted the formation and oxidative decomposition of intermediates and prevented the deposition of intermediates that clogged the pores,allowing more formaldehyde to be adsorbed and oxidized,which increased the activity of the catalyst.This provides new mechanistic evidence for the oxidation of formaldehyde and helps in the development of relatively low-cost materials for formaldehyde purification.
基金supported by the National Key R&D Program of China(Grant No.2023YFB2503900)the National Natural Science Foundation of China(Grant No.52372203)+1 种基金the National Natural Science Foundation of China(Grant No.52202259)the Shandong Province Natural Science Foundation(ZR2022QE093).
文摘High-capacity nickel-rich layered oxides are promising cathode materials for high-energy-density lithium batteries.However,the poor structural stability and severe side reactions at the electrode/electrolyte interface result in unsatisfactory cycle performance.Herein,the thin layer of two-dimensional(2D)graphitic carbon-nitride(g-C_(3)N_(4))is uniformly coated on the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(denoted as NCM811@CN)using a facile chemical vaporization-assisted synthesis method.As an ideal protective layer,the g-C_(3)N_(4)layer effectively avoids direct contact between the NCM811 cathode and the electrolyte,preventing harmful side reactions and inhibiting secondary crystal cracking.Moreover,the unique nanopore structure and abundant nitrogen vacancy edges in g-C_(3)N_(4)facilitate the adsorption and diffusion of lithium ions,which enhances the lithium deintercalation/intercalation kinetics of the NCM811 cathode.As a result,the NCM811@CN-3wt%cathode exhibits 161.3 mAh g^(−1)and capacity retention of 84.6%at 0.5 C and 55°C after 400 cycles and 95.7 mAh g^(−1)at 10 C,which is greatly superior to the uncoated NCM811(i.e.129.3 mAh g^(−1)and capacity retention of 67.4%at 0.5 C and 55°C after 220 cycles and 28.8 mAh g^(−1)at 10 C).The improved cycle performance of the NCM811@CN-3wt%cathode is also applicable to solid–liquid-hybrid cells composed of PVDF:LLZTO electrolyte membranes,which show 163.8 mAh g^(−1)and the capacity retention of 88.1%at 0.1 C and 30°C after 200 cycles and 95.3 mAh g^(−1)at 1 C.
