Methanol(CH_(3)OH)is a liquid hydrogen(H_(2))source that effectively releases H_(2) and is convenient for transportation.Traditional thermocatalytic CH_(3)OH reforming reaction is used to produce H_(2),but this proces...Methanol(CH_(3)OH)is a liquid hydrogen(H_(2))source that effectively releases H_(2) and is convenient for transportation.Traditional thermocatalytic CH_(3)OH reforming reaction is used to produce H_(2),but this process needs to undergo high reaction temperature(e.g.,200℃)along with a catalyst and a large amount of carbon dioxide(CO_(2))emission.Although photocatalysis and photothermal catalysis under mild conditions are proposed to replace the traditional thermal catalysis to produce H_(2) from CH_(3)OH,they still inevitably produce CO_(2) emissions that are detrimental to carbon neutrality.Here,we,for the first time,report an ultrafast and highly selective production of H_(2) without any catalysts and no CO_(2) emission from CH_(3)OH by laser bubbling in liquid(LBL)at room temperature and atmospheric pressure.展开更多
The wet grip of tire has always been the focus because it is related to the personal safety of passengers directly.Many methods were employed to improve the wet grip of tire.Researchers paid more attention on bionics ...The wet grip of tire has always been the focus because it is related to the personal safety of passengers directly.Many methods were employed to improve the wet grip of tire.Researchers paid more attention on bionics method recent years.In nature,tree frogs have high adhesion ability in wet environment,which is mainly due to their footpads having fine polygon grooves(mainly hexagon grooves).To improve the performance of wet grip of tire,from the perspective of bionics,inspired by the footpad of tree frog,the bionic hexagon tread pattern was designed.The friction test was carried out to compare with the common tread patterns such as serrated,striped and square patterns.The results showed that the bionic hexagon tread pattern generally had high friction coefficient and directional stability of friction.The main reason was that the hexagon tread block was less affected by the friction-induced torque and the groove of bionic hexagon tread pattern had better drainage characteristic.The bionic hexagon tread pattern provides new idea and method for the design of tires with high wet grip.展开更多
Frustrated Lewis pairs(FLPs) emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemic...Frustrated Lewis pairs(FLPs) emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemical fuels via hydrogenation/dehydrogenation. Herein, a DFT study was conducted to understand the geometric factors and electronic effects of FLPs on reversible H_2 activation. The Lewis base group mainly contributes to the proton attachment, and influences the kinetics of the H_2 activation. The Lewis acid group mainly relates to the hydride attachment, and affects more significantly on the thermodynamics of H_2 activation. The dimer and quenched structure of FLPs also have a degree of influence on the performance of catalyzed H_2 activation. A series of FLPs with para-substituted phenyl derivatives as LA groups were designed and evaluated. The results indicate that the variation of LA groups has significant impact on thermodynamic energy of dihydrogen adducts but insignificant effect on kinetics. Moreover,we found the thermodynamic energy of products has a good linear relationship with Hammett substituent constants. The solvent effect on H_2 activation was also studied, and polar solvent is beneficial for zwitterionic products. These results should provide deeper insight to understand the relation between FLPs structure and reactivity, which is critical for rational design of more efficient FLPs catalysts for reversible H_2 activation.展开更多
基金The National Natural Science Foundation of China(51832011)the State Key Laboratory of Optoelectronic Materials and Technologies supported this work.
文摘Methanol(CH_(3)OH)is a liquid hydrogen(H_(2))source that effectively releases H_(2) and is convenient for transportation.Traditional thermocatalytic CH_(3)OH reforming reaction is used to produce H_(2),but this process needs to undergo high reaction temperature(e.g.,200℃)along with a catalyst and a large amount of carbon dioxide(CO_(2))emission.Although photocatalysis and photothermal catalysis under mild conditions are proposed to replace the traditional thermal catalysis to produce H_(2) from CH_(3)OH,they still inevitably produce CO_(2) emissions that are detrimental to carbon neutrality.Here,we,for the first time,report an ultrafast and highly selective production of H_(2) without any catalysts and no CO_(2) emission from CH_(3)OH by laser bubbling in liquid(LBL)at room temperature and atmospheric pressure.
基金supported by the National Key R&D Plan(2016YFD0701102)the Graduate Innovation Fund of Jilin University(101832020CX166)+3 种基金the Science-Technology Development Plan Project of Jilin Province(20200403038SF,20200501013GX,20200403006SF)the"13th Five-Year Plan"Scientific Research Foundation of the Education Department of Jilin Province(JJKH20201000KJ,JJKH20211120KJ)the Talent Development Foundation of Jilin Province(2020015)the Fundamental Research Foundation for the Central Universities.
文摘The wet grip of tire has always been the focus because it is related to the personal safety of passengers directly.Many methods were employed to improve the wet grip of tire.Researchers paid more attention on bionics method recent years.In nature,tree frogs have high adhesion ability in wet environment,which is mainly due to their footpads having fine polygon grooves(mainly hexagon grooves).To improve the performance of wet grip of tire,from the perspective of bionics,inspired by the footpad of tree frog,the bionic hexagon tread pattern was designed.The friction test was carried out to compare with the common tread patterns such as serrated,striped and square patterns.The results showed that the bionic hexagon tread pattern generally had high friction coefficient and directional stability of friction.The main reason was that the hexagon tread block was less affected by the friction-induced torque and the groove of bionic hexagon tread pattern had better drainage characteristic.The bionic hexagon tread pattern provides new idea and method for the design of tires with high wet grip.
基金supported by the National Natural Science Foundation of China (Nos. 21502023 and 21473261)the Guangdong Natural Science Funds for Distinguished Young Scholar(No. 2015A030306027)+1 种基金the Guangdong Special Support Plan for High-Level Talent(No. 20153100042090537)supported in part by the high performance grid computing platform of Sun Yat-sen University, the Guangdong Province Key Laboratory of Computational Science, and Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (No. U1501501)
文摘Frustrated Lewis pairs(FLPs) emerge as a new type of bifunctional metal-free catalysts for reversible H_2 activation, which is important for the storage and liberation of H_2 or further controllable utilizing chemical fuels via hydrogenation/dehydrogenation. Herein, a DFT study was conducted to understand the geometric factors and electronic effects of FLPs on reversible H_2 activation. The Lewis base group mainly contributes to the proton attachment, and influences the kinetics of the H_2 activation. The Lewis acid group mainly relates to the hydride attachment, and affects more significantly on the thermodynamics of H_2 activation. The dimer and quenched structure of FLPs also have a degree of influence on the performance of catalyzed H_2 activation. A series of FLPs with para-substituted phenyl derivatives as LA groups were designed and evaluated. The results indicate that the variation of LA groups has significant impact on thermodynamic energy of dihydrogen adducts but insignificant effect on kinetics. Moreover,we found the thermodynamic energy of products has a good linear relationship with Hammett substituent constants. The solvent effect on H_2 activation was also studied, and polar solvent is beneficial for zwitterionic products. These results should provide deeper insight to understand the relation between FLPs structure and reactivity, which is critical for rational design of more efficient FLPs catalysts for reversible H_2 activation.