Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and comp...Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and complex by-products separation.To this end,we introduce the lattice oxygen oxidation mechanism(LOM),propelling a novel UOR route using a modified CoFe layered double hydroxide(LDH)catalyst termed CFRO-7.Theoretical calculations and in-situ characterizations highlight the activated lattice oxygen(O_(L))within CFRO-7 as pivotal sites for UOR,optimizing the reaction pathway and accelerating the kinetics.For the urea overall electrolysis application,the LOM route only requires a low voltage of 1.54 V to offer a high current of 100 mA cm^(-2) for long-term utilization(>48 h).Importantly,the by-product NCO^(-)−is significantly suppressed,while the CO_(2)2/N_(2) separation is efficiently achieved.This work proposed a pioneering paradigm,invoking the LOM pathway in urea electrolysis to expedite reaction dynamics and enhance product selectivity.展开更多
To study statistical characteristics of the random spray autoignition,aviation kerosene was injected transiently into non-vitiated air crossflow in a flow reactor with optical accesses.The operating conditions were re...To study statistical characteristics of the random spray autoignition,aviation kerosene was injected transiently into non-vitiated air crossflow in a flow reactor with optical accesses.The operating conditions were relevant to gas turbine combustor:the air crossflow pressure and temperature were in the range of 1.4-1.7 MPa and 830-947 K,respectively,and the jet-tocrossflow momentum flux ratios were 20,50 and 80.Statistical distributions of random ignition delay times with adequate convergence were estimated based on histograms.The dependences of the distributions on reactor pressure,temperature,and jet-to-crossflow momentum flux ratio were studied.The results show that the resulting distributions appear more concentrated with the increase of air temperature or jet-to-crossflow momentum flux ratio.And then the correlations for the mean and standard deviation of the ignition delay time sample data were developed based on the present results.Compared with the correlations of ignition delay time of homogeneous premixed gas-phase kerosene/air mixture reported in the literature,the results show a greater significance pressure dependence and lower temperature sensitivity of the ignition delay time of nonpremixed kerosene spray.展开更多
基金supported by Fundamental Research Funds for the Central Universities(B220202062)supported by Key Program of National Natural Science Foundation of China(92047201,92047303,52102237)+1 种基金National Science Funds for Creative Research Groups of China(51421006)supported by Postdoctoral Science Foundations of China and Jiangsu Province(2021M690861,2022T150183,2021K065A)。
文摘Urea oxidation reaction(UOR)is proposed as an exemplary half-reaction in renewable energy applications because of its low thermodynamical potential.However,challenges persist due to sluggish reaction kinetics and complex by-products separation.To this end,we introduce the lattice oxygen oxidation mechanism(LOM),propelling a novel UOR route using a modified CoFe layered double hydroxide(LDH)catalyst termed CFRO-7.Theoretical calculations and in-situ characterizations highlight the activated lattice oxygen(O_(L))within CFRO-7 as pivotal sites for UOR,optimizing the reaction pathway and accelerating the kinetics.For the urea overall electrolysis application,the LOM route only requires a low voltage of 1.54 V to offer a high current of 100 mA cm^(-2) for long-term utilization(>48 h).Importantly,the by-product NCO^(-)−is significantly suppressed,while the CO_(2)2/N_(2) separation is efficiently achieved.This work proposed a pioneering paradigm,invoking the LOM pathway in urea electrolysis to expedite reaction dynamics and enhance product selectivity.
基金supported by the National Natural Science Foundation of China(Nos.91641109 and 61827802)。
文摘To study statistical characteristics of the random spray autoignition,aviation kerosene was injected transiently into non-vitiated air crossflow in a flow reactor with optical accesses.The operating conditions were relevant to gas turbine combustor:the air crossflow pressure and temperature were in the range of 1.4-1.7 MPa and 830-947 K,respectively,and the jet-tocrossflow momentum flux ratios were 20,50 and 80.Statistical distributions of random ignition delay times with adequate convergence were estimated based on histograms.The dependences of the distributions on reactor pressure,temperature,and jet-to-crossflow momentum flux ratio were studied.The results show that the resulting distributions appear more concentrated with the increase of air temperature or jet-to-crossflow momentum flux ratio.And then the correlations for the mean and standard deviation of the ignition delay time sample data were developed based on the present results.Compared with the correlations of ignition delay time of homogeneous premixed gas-phase kerosene/air mixture reported in the literature,the results show a greater significance pressure dependence and lower temperature sensitivity of the ignition delay time of nonpremixed kerosene spray.
