Water-Stable Pillared Three-Dimensional Zn–V Bimetal–Organic Framework for Promoted Electrocatalytic Urea Oxidation

Abstract

Urea oxidation reaction (UOR) is one of the potential routes in which urea-rich wastewater is used as a source of energy for hydrogen production. Metal−organic frameworks (MOFs) have promising applications in electrocatalytic processes, although there are still challenges in identifying the MOFs' molecular regulation and obtaining practical catalytic systems. The current study sought to synthesize [Zn 6 (IDC) 4 (OH) 2 (Hprz) 2 ] n (Zn-MOF) with three symmetrically independent Zn(II) cations connected via linear N-donor piperazine (Hprz), rigid planar imidazole-4,5-dicarboxylate (IDC 3− ), and −OH ligands, revealing the 3,4T1 topology. The optimized noblemetal-free Zn 0.33 V 0.66 -MOF/NF electrocatalysts show higher robustness and performance compared to those of the parent Zn monometallic MOF/NF electrode and other bimetallic MOFs with different Zn−V molar ratios. The low potential of 1.42 V (vs RHE) at 50 mA cm −2 in 1.0 M KOH with 0.33 M urea required by the developed Zn 0.33 V 0.66 -MOF electrode makes its application in the UOR more feasible. The availability of more exposed active sites, ion diffusion path, and higher conductivity result from the distinctive configuration of the synthesized electrocatalyst, which is highly stable and capable of synergistic effects, consequently enhancing the desired reaction. The current research contributes to introducing a practical, cost-effective, and sustainable solution to decompose urea-rich wastewater and produce hydrogen.

Copper-Based Bio-MOF/GO with Lewis Basic Sites for CO2 Fixation into Cyclic Carbonates and C–C Bond-Forming Reactions

“…The C–O alkoxy stretching vibration and the epoxy or peroxide functional group were reported at 1041 and 866 cm –1 , respectively . Besides, the two weak peaks observed for the bio-MOF­(Cu)’s FTIR spectrum at 3211 and 3237 cm –1 show a connection with amine’s N–H stretching in adenine. , The bending bands of N–H are shown in the band at 1612 cm –1 , , and the C–H stretching within the adenine structure is revealed by the bands at 1300–1450 cm –1 . − Figure b shows some low-intensity peaks at the 600–700 cm –1 range as the characteristic of metal–O stretching vibrations. ,− Investigations of FTIR spectra for all bio-MOF­(Cu)/GO nanocomposites confirm that most peaks for GO and bio-MOF­(Cu) are retained without any significant changes. Besides, according to Figure b, the properties of bio-MOF­(Cu) were not affected by GO.…”

Metal–organic frameworks (MOFs) for hybrid water electrolysis: structure–property–performance correlation

“…Similarly, Gao et al introduced Fe to develop Ni-MIL-53-NH 2 for UOR, 99 while high-valent vanadium (V) was incorporated into Zn-MOF to fabricate ZnV-MOF for excellent UOR activity. 100 The optimized Zn 0.66 V 0.33 -MOF exhibited a potential of 1.48 V vs . RHE at a current density of 10 mA cm −2 for OER, whereas only 1.37 V vs .…”

Structure–property–performance relationship of vanadium- and manganese-based metal–organic frameworks and their derivatives for energy storage and conversion applications

“…At the same time, they can also perform various tasks as their metal nodes and ligands are easily modified, 68 making them suitable candidates as catalysts and electrode materials. 69–71 MOFs have evenly distributed catalytic sites, large surface areas, open channels for substrate diffusion to access the active sites, and highly recyclable structures (Fig. 4).…”