In general, methyl orange (MO) can be degraded by an electrocatalytic oxidation process driven by a power source due to the generation of superoxidative hydroxyl radical on the anode. Here, we report a hybrid energy cell that is used for a self-powered electrocatalytic process for the degradation of MO without using an external power source. The hybrid energy cell can simultaneously or individually harvest mechanical and thermal energies. The mechanical energy was harvested by the triboelectric nanogenerator (TENG) fabricated at the top by using a flexible polydimethysiloxane (PDMS) nanowire array with diameters of about 200 nm. A pyroelectric nanogenerator (PENG) was fabricated below the TENG to harvest thermal energy. The power output of the device can be directly used for electrodegradation of MO, demonstrating a self-powered electrocatalytic oxidation process. KEYWORDS: Hybrid energy cell, triboelectric nanogenerator, pyroelectric nanogenerator, self-powered, methyl orange, electrodegradation W ith the growing threat of pollution, global warming, and energy crises, the search for cost-effective, renewable and green energy sources to meet the global energy demands of the future is one of the most urgent challenges. 1 Currently, there are three typical physics effects that can be used to fabricate nanogenerators (NGs) to harvest energy from the ambient environment. Both piezoelectric and triboelectric effect can be used to harvest the mechanical energy from irregular mechanical vibrations. 2−5 The pyroelectric effect can be used to harvest the thermal energy from the time-dependent temperature fluctuations. 6−8 Since the mechanical and thermal energies are not always available at the same time in the environment, it is necessary to develop a hybrid energy cell technology to simultaneously/individually harvest both energies by using an integrated device. Although some attempts about the hybrid cells have been achieved, 9−11 there has no report about a hybrid energy cell that consists of a triboelectric nanogenerator (TENG) and a pyroelectric nanogenerator (PENG) for harvesting mechanical and thermal energies.The purpose of developing self-powered nanotechnology is to use NGs instead of batteries or other energy storage/supply systems to power small electronic devices (such as LCD, LED) or achieve some electrochemical applications (such as electrodeposition). 12−14 Although some experiments about the selfpowered electrochemical applications have been demonstrated, 14 there has no report about the self-powered degradation of dyeing wastewater by the electrocatalytic oxidation. Usually, wastewater from textile manufacturing contains dyes, which must be removed before it can be discharged. The purification of dyeing wastewater by electrochemical techniques has been proven to be a very effective method, where it has the simple equipment, easy operation, lower temperature requirements and no sludge formation. 15−17 Although the feasibility of electrochemical degradation of dyes [such as methyl orange (MO),...

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Superhydrophilic and superhydrophobic surfaces were studied with an eye to industrial applications and use as research tools. Conventional methods involve complex and time-consuming processes and cannot feasibly produce large-area three-dimensional surfaces. Here, we report robust and large-area alumina nanowire structures with superhydrophobic or superhydrophilic properties, generated by an inexpensive single-step anodization process that can routinely create arbitrary three-dimensional shapes. This process is expected to open up diverse applications.

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