Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to i...Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous electrolytes.Herein,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) molecules.The eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic sites.As a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell.This work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.展开更多
Reaction of a tripodal ligand, N,N＇,N＇＇-tris（3-pyridinyl） phosphoric trimide（TPPA） and CuBr_2·2H_2O result in the assembly of a new polymeric copper coordination polymer, which was characterized by single-...Reaction of a tripodal ligand, N,N＇,N＇＇-tris（3-pyridinyl） phosphoric trimide（TPPA） and CuBr_2·2H_2O result in the assembly of a new polymeric copper coordination polymer, which was characterized by single-crystal diffraction, infrared spectroscopy and elemental analysis. The polymer crystallizes in the triclinic system, space group P1 with a = 9.0964（5）, b = 10.2592, c = 10.5822（8） A, V = 933.01（9） A3, Z = 2, C_（30）H_（24）Br_4Cu_3N_（12）O_2P_2, M_r = 985.02, D_c = 1.753 g/cm3, F（000） = 4072 and μ（MoKα） = 0.746 mm^（-1）. The final R and w R are 0.0588 and 0.1329 for 4260 observed reflections with I 〉 2σ（I）. Cu（Ⅰ） is tetrahedrally coordinated and Cu（Ⅱ） center adopts square planar coordination geometry. Because of the flexibility of the TPPA ligands, the pyridyl rings rotate though a certain angle and three pyridyl rings on the same TPPA rotate by about 45° with respect to the central P=O groups. TPPA ligand acts as a tridentate ligand and is coordinated with three metal centers with its pyridyl donors to form a 2D-sheet like structure, and it is further connected by N-H···O and N-H···Br, resulting in a 3D network packing. Oxidation states of the metal center have been determined by bond valence sum calculation.展开更多
The extraction ability of organophosphorus extractant D2EHPA(di-2-ethylhexyl phosphoric acid) and hydroximic extractant Lix984N are investigated by the extraction equilibrium experiments.Effects of carrier concen-trat...The extraction ability of organophosphorus extractant D2EHPA(di-2-ethylhexyl phosphoric acid) and hydroximic extractant Lix984N are investigated by the extraction equilibrium experiments.Effects of carrier concen-tration and organic/aqueous volume ratio on the mass transfer of hollow fiber renewal liquid membrane(HFRLM) are studied.Results show that,in the extracting process,kerosene and n-heptane are more suitable than methyl-isobutyl ketone,butylacetate and benzene as the diluents of D2EHPA or Lix984N.The favorable feed pH is 4.4 for D2EHPA and 2.6 for Lix984N.The mass transfer flux of HFRLM increases with carrier concentration and finally reaches a plateau.The mass transfer flux and the overall transfer coefficient increase with the organic/aqueous volume ratio,reach the maximum and then decrease.展开更多
基金supported by the Climate Change Response Project (NRF-2019M1A2A2065612)the Brainlink Project (NRF2022H1D3A3A01081140)+3 种基金the NRF-2021R1A4A3027878 and the No. RS-2023-00212273 funded by the Ministry of Science and ICT of Korea via National Research Foundationresearch funds from Hanhwa Solutions Chemicals (1.220029.01)UNIST (1.190013.01)supported by the Institute for Basic Science (IBS-R019-D1)。
文摘Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous electrolytes.Herein,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) molecules.The eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic sites.As a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell.This work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.
基金supported by the Natural Science Foundation of Shanxi province(2012021005-2)Technology Foundation for Selected Overseas of Shanxi
文摘Reaction of a tripodal ligand, N,N＇,N＇＇-tris（3-pyridinyl） phosphoric trimide（TPPA） and CuBr_2·2H_2O result in the assembly of a new polymeric copper coordination polymer, which was characterized by single-crystal diffraction, infrared spectroscopy and elemental analysis. The polymer crystallizes in the triclinic system, space group P1 with a = 9.0964（5）, b = 10.2592, c = 10.5822（8） A, V = 933.01（9） A3, Z = 2, C_（30）H_（24）Br_4Cu_3N_（12）O_2P_2, M_r = 985.02, D_c = 1.753 g/cm3, F（000） = 4072 and μ（MoKα） = 0.746 mm^（-1）. The final R and w R are 0.0588 and 0.1329 for 4260 observed reflections with I 〉 2σ（I）. Cu（Ⅰ） is tetrahedrally coordinated and Cu（Ⅱ） center adopts square planar coordination geometry. Because of the flexibility of the TPPA ligands, the pyridyl rings rotate though a certain angle and three pyridyl rings on the same TPPA rotate by about 45° with respect to the central P=O groups. TPPA ligand acts as a tridentate ligand and is coordinated with three metal centers with its pyridyl donors to form a 2D-sheet like structure, and it is further connected by N-H···O and N-H···Br, resulting in a 3D network packing. Oxidation states of the metal center have been determined by bond valence sum calculation.
基金Supported by the Program for New Century Excellent Talents in University（NCET-05-0122） the National Natural Science Foundation of China（20576008 20706003）
文摘The extraction ability of organophosphorus extractant D2EHPA(di-2-ethylhexyl phosphoric acid) and hydroximic extractant Lix984N are investigated by the extraction equilibrium experiments.Effects of carrier concen-tration and organic/aqueous volume ratio on the mass transfer of hollow fiber renewal liquid membrane(HFRLM) are studied.Results show that,in the extracting process,kerosene and n-heptane are more suitable than methyl-isobutyl ketone,butylacetate and benzene as the diluents of D2EHPA or Lix984N.The favorable feed pH is 4.4 for D2EHPA and 2.6 for Lix984N.The mass transfer flux of HFRLM increases with carrier concentration and finally reaches a plateau.The mass transfer flux and the overall transfer coefficient increase with the organic/aqueous volume ratio,reach the maximum and then decrease.
