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In this study, we report on how to design efficient catalysts for glucose oxidation via the transitional metal doping of nanohybrids of polyoxometalates (POMs) and metal-organic frameworks (MOFs). ZIF-67, a cobalt-based MOF, as well as phosphomolybdic acid (PMo), were used as precursors for the fabrication of pyrolyzed PMo@ZIF-67 (T-PMo@ZIF-67). A different amount of Ni2+ was doped into PMo@ZIF-67 to produce NixCoy@T-PMo@ZIF-67. Among them, Ni2Co2@T-PMo@ZIF-67 had the best performance. The power density of the fuel cell that used Ni2Co2@T-PMo@ZIF-67 as an anode catalyst was 3.76 times that of the cell that used active carbon as an anode catalyst. SEM and EDS mapping results indicate that Ni2Co2@T-PMo@ZIF-67 has a spherical structure and rough surface, and elements such as cobalt, nickel, and molybdenum are evenly distributed. XRD characterization indicates that Co3O4, CoMoO4, CoNiO4, and MoNiO4 co-exist in the composites. It is supposed that Co2+, Mo6+, and Ni2+ in the composites may have synergistic effects on the catalytic oxidation of glucose. [ABSTRACT FROM AUTHOR]

Collecting energy from the ambient environment through green and sustainable methods is highly expected to alleviate pollution and energy problems worldwide. Here, we report a facile and flexible hydrovoltaic generator capable of utilizing natural water evaporation for sustainable electricity production. The generator was fabricated by coating nano-Al2O3 on a twistable polyethylene terephthalate film. An open circuit voltage of 1.7 V was obtained on a piece of centimeter-sized hydrovoltaic generator under ambient conditions. The supercapacitor charged by the hydrovoltaic device can power a mini-motor efficiently. Moreover, by expanding the size or connecting it in series/parallel, the energy output of the generator can be further improved. Finally, the influence factors and the mechanism for power generation were primarily investigated. Electrical energy is produced by the migration of water through charged capillary channels. The environmental conditions, the properties of the solution and the morphology of the film have important effects on the electrical performance. This study is anticipated to offer enlightenment into designing novel hydrovoltaic devices, providing diverse energy sources for various self-powered devices and systems. [ABSTRACT FROM AUTHOR]

Polyoxometalates (POMs) are three-dimensional materials with unique, exceptional physical and chemical characteristics. The performance of POM-derived materials is anticipated to be enhanced by the combination of POM and metal–organic frameworks (MOFs) due to the high surface areas of MOF materials. In this study, three kinds of T-POMs@ZIF-67 (T-PMo@ZIF-67, T-SiW@ZIF-67, and T-PW@ZIF-67) were prepared by doping a cobalt-based MOF (ZIF-67) with three POMs (phosphomolybdic acid, silicotungstic acid, and phosphotungstic acid). The results show that the power density of the T-PMo@ZIF-67 catalyst anode is 3.08 times that of the blank control anode and 1.34 times that of the CoMoO4 catalyst. These findings suggest that the synthesis of MOF derivatives by doping MOFs with POM will have significant potential for use in the fuel cell industry. [ABSTRACT FROM AUTHOR]