chemical) available in our surrounding, mechanical energy (variable frequency and amplitude) is the most urgent valuable energy because of its greater accessibility anywhere and anytime. [ 1,4 ] Several approaches have been reported to harvest mechanical energy from different mechanical energy sources, such as movement of body (fi nger imparting, pushing, stretching, bending, twisting, etc.), talking, breathing, air fl owing, vibration, friction, water falling, and hydraulic forces (ocean waves, blood fl ow, etc.) to power up various portable electronic devices. [4][5][6][7][8][9][10][11] Thus, human motion based energy harvesting technology is of great interest due to its emergent trends to power up portable smart electronic devices. [ 12,13 ] Recently, piezoelectric nanogenerators (PNGs) and triboelectric nanogenerators (TENGs) have attracted great attention for harvesting mechanical energy under different small mechanical and biomechanical actions with variable amplitude and frequency present in our living environment. [ 12,14 ] Although, TENGs have exhibited high output with high energy conversion efficiency up to ≈55%, they are unfavorable for long term uses (low durability) due to wear and tear at the two contact surfaces and industrial packaging problem in open environment for humidity. [ 15,16 ] Thus, to realize fully independent, scalable, sustainable, and wireless operation of low power-consuming self-powered devices and systems, development of PNGs with large power generating performance, high sensitivity and energy conversion effi ciency, and prominent mechanical durability is highly important. A lot of research works have been reported to fabricate PNGs using various semiconducting nanomaterials, e.g., ZnO, InN, GaN, Te, and lead based Pb(Zr,Ti)O 3 , (PZT) and lead free ceramics (BaTiO 3 , ZnSnO 3 , NaNbO 3 , KNbO 3 ) with superior energy conversion effi ciency. [17][18][19][20][21][22][23][24][25][26] But they have limitations, e.g., brittle, heavy weight, poisonous, low durability compared to piezoelectric polymers which retain their fl exibility and higher strain level to Till date, fabrication of piezoelectric nanogenerator (PNG) with highly durable, high power density, and high energy conversion effi ciency is of great concern. Here a fl exible, sensitive, cost effective hybrid piezoelectric nanogenerator (HPNG) developed by integrating fl exible steel woven fabric electrodes into poly(vinylidene fl uoride) (PVDF)/aluminum oxides decorated reduced graphene oxide (AlO-rGO) nanocomposite fi lm is reported where AlO-rGO acts as nucleating agent for electroactive β-phase formation. The HPNG exhibits reliable energy harvesting performance with high output, fast charging capability, and high durability compared with previously reported PVDF based PNGs. This HPNG is capable for harvesting energy from a variety and easy accessible biomechanical and mechanical energy sources such as, body movements (e.g., hand folding, jogging, heel pressing, and foot striking, etc.) and machine vibration. The HPNG exhib...

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Palladium(0) has been immobilized into the silica-based mesoporous material to develop catalyst Pd(0)-MCM-41, which is found to be highly active in carbon-carbon coupling reactions. [Pd(NH3)4]2+ ions have been incorporated into the mesoporous material during synthesis of MCM-41 and subsequently upon treatments with hydrazine hydrate Pd2+ ions present in mesoporous silica matrix were reduced to Pd(0) almost instantaneously. The catalyst has been characterized by small-angle X-ray diffraction, N2 sorption, and transmission electron microscopy (TEM). TEM and surface area measurements clearly demonstrate that the immobilization of Pd(0) into the mesoporous silica has a significant effect on pore structure of the catalyst. Nevertheless, after immobilization of palladium the meso-porosity of the material is retained, as evidenced in the nitrogen sorption measurement. The TEM micrograph shows that both MCM-41 and Pd(0)-MCM-41 have similar types of external surface morphology; however, Pd(0)-MCM-41 was less ordered. Pd(0)-MCM-41 showed high catalytic activity toward carbon-carbon bond formation reactions like Heck and Sonogashira coupling, as evidenced in high turn-over numbers. In contrast to many other Pd-based catalysts reported so far, Pd(0)-MCM-41 acts as a truly heterogeneous catalyst in C-C coupling reactions. Notably, the new heterogeneous catalyst is found to be efficient in the activation of arylchloride to give impressive conversion in cross coupling (15-45% for Heck and 30% for Sonogashira) reactions under mild conditions.

We have shown an enhancement in the output performance of PDMS/ZnSnO3/MWCNT based TENGs through modification of dielectric constant, internal resistance, and surface patterning.