Contact electrification is a direct triboelectrification method for producing current through charge transfer when two different differentiated materials have brought into contact. For the first time, we developed a simple triboelectric nanogenerator (TENG) where the electronic charges were realized through contact separation mode between sand-polished Kapton (SPK) and Al surface. Here, we demonstrated the energetic interfacial contact between these surfaces and observed satisfactory output performance. The novel SPK-TENG produced 40 V and 2.8 µA, of open-circuit voltages (V_oc) and short-circuit currents (I_sc) at 4 Hz, respectively. Mainly, the SPK-TENG was dramatically increased up the performance of TENG, up to 40% of V_oc and 42% of I_sc, with respect to the Kapton film because the mobility of electrons is very high on the device surface compared to the other pristine Kapton film. The fabricated SPK-TENGs were good candidates for satisfying the need for alternative contact separation mode TENGs. GRAPHICAL ABSTRACT

The detection of sustainable materials from naturally available resources using a simple fabrication process is highly important for novel research. Here, we used chitosan-PVA (Chs-PVA) blend films via layer-by-layer casting technologies for generating power through mechanical induction through triboelectric nanogenerators. The proposed Chs-PVA biodegradable film (i.e., thickness of 60 ± 5 μm) is facile, ecofriendly, highly flexible, mechanically strong, cost-effective, and easy to scale up. FT-IR analysis of the ChS-PVA blend membrane showed the strong interactions between the amines of ChS and hydroxyl groups of PVA through chemical cross-linking by hydrogen bonding. More importantly, the triboelectric nanogenerators (TENG) values of ChS-PVA films were 3–4 orders of magnitude lower than chitosan films reported before. Layer-on-layer cast films in particular exhibited high tensile strength (15.8 ± 1 MPa) and were more than three times stronger than other polyelectrolyte multilayer films. Both types of films remained stable in an acidic environment. Furthermore, the layer-on-layer-assembled films presented greater open circuit voltage (Voc) and short circuit current (Isc) values compared to pure ChS and PVA films. The ChS-PVA membrane can be used as a functional layer to produce charges by collecting get-up-and-go through vertical contact and separation mode TENG counters to the PVDF membrane. The enhancement of Voc and Isc of ChS-PVA TENG were 244 and 1,080% from ChS TENG. Where in the case of PVA TENG, the enhancement of Voc and Isc were increased by 633 and 2,888%, respectively due to the availability of free loan pair on the -NH₂ and -OH functional groups. The novel ChS-PVA TENG is a potential candidate for satisfying the tight requirement of an optimized energy harvesting device as an alternate bio-material option for contact-separation mode TENGs.

In this article, a zirconia-based nano-catalyst (Nano-ZrO₂), with intermolecular C-N bond formation for the synthesis of various benzimidazole-fused heterocycles in a concise method is reported. The robustness of this reaction is demonstrated by the synthesis of a series of benzimidazole drugs in a one-pot method. All synthesized materials were characterized using ¹HNMR, ¹³CNMR, and LC-MS spectroscopy as well as microanalysis data. Furthermore, the synthesis of nano-ZrO₂ was processed using a standard hydrothermal technique in pure form. The crystal structure of nano-ZrO₂ and phase purity were studied, and the crystallite size was calculated from XRD analysis using the Debye–Scherrer equation. Furthermore, the antimicrobial activity of the synthesized benzimidazole drugs was evaluated in terms of Gram-positive, Gram-negative, and antifungal activity, and the results were satisfactory.

In this article, the oxidation of alcohols into carbonyl compounds was studied in oxygen atmospheres using a copper oxide on graphene oxide (CuO@GO) nano composites catalyst, synthesized by the wet chemistry method. CuO@GO nano composites were prepared from GO, and CuO NPs by the sol-gel method. The transformation of aromatic alcohols into corresponding carbonyl compounds in good-to-high yields were observed using the CuO@GO catalyst under an oxygen atmosphere. Synthesized CuO@GO was confirmed by FT-IR, XRD, XPS, TEM, FE-SEM, TEM, and SEM analyses, and revealed intercalation of CuO-NPs on/in GO nano sheets through the chelation of Cu⁺² ions with CO, COOH, and OH groups presenting on the GO nano sheets. The catalytic activity of CuO@GO nano composites for the conversion of alcohols into carbonyl compounds were evaluated through TOF (2.56 × 10⁻³ mol g⁻¹ min⁻¹). The use of CuO@GO has shown catalytic activity and recyclability with a high conversion of alcohols to ketones. We assume that the proposed CuO@GO catalyst can be used for other key organic transformations and will be evaluated in the future.

We report the synthesis of thermally heated pop-up reduced graphene oxide (Pop-rGO) and its nanofluid (Pop-rGO-Nf) in DI water for extended critical heat flux (CHF) in a nucleate pool boiling experiment. When Pop-rGO-Nf is boiled over a nichrome (NiCr) wire heater the CHF values were increased up to 132%, 156%, and 175% with increasing concentrations of 0.0005 vol%, 0.001 vol%, and 0.005 vol% at heat fluxes of q′′ = 264 333 kW m⁻², 339 202 kW m⁻², and 327 895 kW m⁻², respectively, because of the higher surface area of 430 m² g⁻¹. We also found a decrease in the CHF value from 0.05 vol% (175%) to 0.01 vol% (153%) for Pop-rGO-Nf due to the nanofluid concentration reaching the saturation point. After nucleate pool boiling, the developed Pop-rGO-Nf built-up layer on the NiCr wire surface showed regular π–π stacking with novel micro-rippled structures having uniform nanocavities and nanochannels. The nanocavities strongly helped vapor bubbles to escape from the NiCr wire surface. In addition, the nanochannels were formed by hydrogen bonding of adjacent carboxyl groups of each Pop-rGO nanosheet. The surface hydrophobicity of the built-up layers increased with the increase of the concentration of the Pop-rGO-Nfs, and the surface morphology, roughness average (R_a) and hydrophobicity were determined using FE-SEM, AFM and contact angle (CA) analysis. In our present investigation, during and after the nucleate CHF experiments with Pop-rGO-Nfs, for the first time, we obtained a higher CHF value of 175% at 0.01 vol% and a higher CA of 118° obtained at 0.05 vol%, due to the increase in surface hydrophobicity and the novel micro-rippled structures. We anticipate that the present results suggest that pool boiling employing Pop-rGO-Nf can dissipate the critical heat flux of electronic chips to a greater extent, allowing the enhancement of the cooling performance in existing two-phase heat transfer devices.

Harvesting of flow current through implanted hydrophobic surface within silicone pipe as liquid nanogenerators where Tap water (TW), and DI water (DIw) as liquid reservoirs to successfully convert induced mechanical energy into electrical energy. Here, we used a commercial PTFE film for the generation of a hydrophobic surface as a source of mechanical energy. The surface roughness of the hydrophobic surface is confirmed using atomic force microscopy, and contact angle analyses. The generation of power through the interaction of TW and DI with inbuilt PTFE in silicone tube is described. The higher output voltage (Voc), and short circuit currents (Isc) were attained through an interaction of TW and DIw with N-PTFE. The lower Voc, and Isc’s were produced when DI water interacts with N-PTFE electrode, whereas TW produced higher V_oc and I_sc’s, respectively, due to a lack of free mobile ions in DIw than TW. The TW-Sh-TENG and DIw-Sh-TENG are produced the maximum peak-to-peak Voc, and Isc of 29.5 V and 17.4 V and 3.7 μA, and 2.9 μA, respectively. Significant power output enhancement of ~ 300% from TW-Sh-TENG from DIw-N-TENG due to the formation of higher surface roughness and lead to the slipping of water droplets by super-hydrophobicity.