非贵金属催化剂在羟甲基糠醛电氧化增值中的应用 高等学校化学学报    2023, 44 (5): 20220710-.   DOI:10.7503/cjcu20220710

Fig.8 Electrochemical HMFOR performance using NiFe⁃LDHs catalyst^[57]
（A） HPLC chromatogram traces of the various products at different reaction times following an HMF electrochemical oxidation reaction； （B） digital photograph showing the color change of the anodic electrolyte during the electrochemical HMF oxidation process； （C） concentration changes of HMF and its oxidation products with the time of chronoamperometric tests at 1.33 V vs. RHE； （D） HMF concentration changes during four successive cycles.
Copyright 2018， American Chemical Society.

正文中引用本图/表的段落

氧化物在高电势的碱性环境中极易转化为相应的氢氧化物以及羟基氧化物. 因此， 也有学者直接制备过渡金属氢氧化物和羟基氧化物并用于HMFOR. 如NiFe-LDHs催化剂在20 mA/cm2电流密度下的HMFOR电势仅为1.32 V， 远低于OER的电极电势（1.57 V）［57］. 在1.33 V（vs. RHE）条件下对HMF的选择性进行测试， 结果表明FDCA的产率和法拉第效率接近99.4%（图8）. 在进一步提高电势的情况下， HMF的转化率会降低， 这主要是因为OER反应的发生； 降低电势至低于OER起始电位时FDCA的产率则会进一步提高至接近100%， 然而反应速度只有8.33×10-6 mmol/s［57］. 这些结果表明NiFe LDHs是将HMF氧化为FDCA的最具有活性和选择性的催化剂之一.

本文的其它图/表

• Fig.1  Schematic illustration of HMF and its possible oxidation products
• Table 1  The value-added products derived from HMFOR and their possible applications
• Fig.2  TEM image of Pd₁Au₂/C catalyst(A) and product distribution on Pd₁Au₂/C for the oxidation of 0.02 mol/L HMF in 0.1 mol/L KOH(B)^[28]Copyright 2014， the Royal Society of Chemistry.
• Fig.3  Schematic of the electrochemical cells with Co⁃P/CF catalyzed HMF oxidation(A), concentrations of HMF and oxidation products over passed charge during the chronoamperometry experiment conducted at 1.423 V in 1.0 mol/L KOH containing 50 mmol/L HMF(B)^[47], conversion and yield(%) changes of HMF and its oxidation products during the electrochemical oxidation of HMF at 1.54 V in a 0.5 mol/L borate buffer solution containing 5 mmol/L HMF and 7.5 mmol/L TEMPO(C)^[48]（A， B） Copyright 2016， American Chemical Society； （C） Copyright 2015， Nature Publishing Group.
• Table 2  Typical non-precious metal catalysts and their HMFOR performances
• Table 3  The oretical ΔH_f^FERE and experimental ΔH_f^exp of several typical transition metal-based compounds^[60]
• Fig.4  Morphological features of Ni₂P NPA/NF and conversation of FDCA^[50]（A） XRD pattern of Ni₂P NPA/NF with the corresponding standard patterns of Ni₂P and Ni； （B， C） SEM images of Ni₂P NPA/NF with different magnifications； （D） SEM and the corresponding elemental mapping images of Ni₂P NPA/NF； （E） LSV curves of Ni₂P NPA/NF at a scan rate of 2 mV/s in 1.0 mol/L KOH with and without 10 mmol/L HMF； （F） conversion and yield（%） changes of HMF and its oxidation products during the electrochemical oxidation of HMF at 1.423 V（vs. RHE） in 1.0 mol/L KOH with 10 mmol/L HMF； （G） faradaic efficiencies of Ni₂P NPA/NF for FDCA production under three successive electrolysis cycles.Copyright 2016， Wiley-VCH GmbH.
• Fig.5  Sum Frequency Generation(SFG) spectra recorded at the working electrode/electrolyte interface after running the cell at various voltages for 90 min(A) and by monitoring the reaction at different times at 1.45 V(vs. RHE) in 1 mol/L KOH and 20 mmol/L HMF(B)^[51]Copyright 2019， Wiley-VCH GmbH.
• Table 4  Typical transition metal Xides and their derivates(real active materials) during anodic reactions
• Fig.6  Physical characterizations of the reconstructed Ni(OH)₂/NiFeP after potentiostatic HMFOR polarization
• Fig.7  Theoretical calculation results to unravel the underlying HMFOR mechanisms on CuO⁃PdO catalyst^[83]（A） Adsorption configuration of the HMF and OH on CuO（111） surface and the as-designed CuO-PdO； （B） HMF and OH adsorption free energy； （C） free energy diagram and adsorption configurations of HMFOR intermediates on CuO（111） and CuO⁃PdO； （D） promoting mechanism of the HMFOR； （E） the charge density difference of PdO on CuO（111） surface.Copyright 2022， Wiley-VCH GmbH.