Cu/Ag Complex Modified Keggin-Type Coordination Polymers for Improved Electrochemical Capacitance, Dual-Function Electrocatalysis, and Sensing Performance

Abstract

Different metal−organic units were introduced into the {PMo 12 } polyoxometalate (POM) system to yield three porous coordination polymers with distinct characteristics, {Cu(pra) 2 } [{Cu-(pra) 2 } 3 {PMo 11 VI Mo V O 40 }] (1), [{Ag 5 (pz) 6 (H 2 O) 0.5 Cl}{PMo 11 VI Mo V O 40 }] (2), and [{Cu 3 (bpz) 5 (H 2 O)}{PMo 12 O 40 }](3) (pra = pyrazole; pz = pyrazine; bpz = benzopyrazine), via an in situ hydrothermal method. In comparison with the maternal Keggin cluster and most reported POM electrode materials, compounds 1−3 exhibit larger specific capacitances (672.2, 782.1, and 765.2 F g −1 at a current density of 2.4 A g −1 , respectively), superior cyclic stability (91.5%, 89.3%, and 87.8% of cycle efficiency after 5000 cycles, respectively), and boosted conductivity, which may be attributed to the introduction of metal−organic units. The result indicates that metal−organic units can effectively enhance the capacitance performance of POMs. This may be due to the fact that they provide additional redox centers, induce the formation of stable porous structures, and improve ion/electron transfer efficiency. Compounds 1−3 present excellent electrocatalytic activity in reducing peroxide (H 2 O 2 ) and oxidizing ascorbic acid (AA). In addition, compound 2 shows an outstanding sensing performance detection of AA and H 2 O 2 .

“Tree”-like Multidentate Ligand-Assisted Synthesis of Polymolybdate-Based Architectures with Multinuclear Metal Clusters: Supercapacitor and Electrochemical Sensing Performances

“…The C s values were 823.8, 740.0, 631.3, 500.0, 431.3, and 350 F g –1 for the 2 -GCE, 798.8, 732.5, 656.3, 562.5, 487.5, and 425.0 F g –1 for 3 -GCE at the same current densities as those for the 1 -GCE. For BOHU-1 and BOHU-3 , their different capacitance performances can be attributed to different POMs and their different distinct structures . In BOHU-3 , the MnMo 9 anions could expose more active sites to enhance the capacitance and rate performance (Figure c).…”

“…For BOHU-1 and BOHU-3, their different capacitance performances can be attributed to different POMs and their different distinct structures. 21 In BOHU-3, the MnMo 9 anions could expose more active sites 22 to enhance the capacitance and rate performance (Figure 4c). For BOHU-1 and BOHU-2, different metal ions have a greater influence on the electrochemical storage capacity.…”

Polyoxometalate-Incorporated Metal-Organic Network as a Heterogeneous Catalyst for Selective Oxidation of Aryl Alkenes

“…One of the merits of POM-incorporated metal-organic networks is that they can be easily tailored by a judicious choice of metal ions, bridging organic ligands and polyanions. 30 Numerous studies reported that transition metal (TM) ions (Co, Zn, etc.) can act as catalytic centers for various oxidation processes.…”

Four Anderson-type [TeMo6O24]6−-based metal–organic complexes with a new bis(pyrimidine)-bis(amide): multifunctional electrochemical and adsorption performances

“…For instance, Zhou's group has reported three POMOCs containing Keggin-type polyoxometalates, in which complex 2 exhibited excellent sensing and detection properties for H 2 O 2 and AA. 27 Bromate (KBrO 3 ) and nitrite (KNO 2 ) can be used as food additives and preservatives, respectively, but excessive consumption will cause great harm to the human body. 28–30 Therefore, their control and detection are necessary.…”