Abstract The development of sustainable, cost-effective, and high-performance counter electrodes (CEs) remains a major challenge in dye-sensitized solar cell (DSSC) research. Although Pt remains the benchmark CE because of its excellent electrocatalytic activity and electrical conductivity, its scarcity and high cost motivate the development of efficient Pt-free alternatives. Herein, we report a novel Pt-free counter electrode based on a MOF-derived ZnO/NiCo2O4/Nb2C MXene composite for DSSC applications. The counter electrode materials were synthesized by a hydrothermal method and systematically characterized to evaluate their structural, morphological, and photovoltaic properties. X-ray diffraction analysis revealed characteristic peaks at 36.3°, 34.1°, and 40.3°, confirming the formation of ZnO, NiCo2O4, and Nb2C. The optimized ZnO/NiCo2O4/Nb2C MXene counter electrode achieved a power conversion efficiency (PCE) of 8.08%, comparable to that of Pt-based DSSCs under standard illumination. This enhanced performance is attributed to the synergistic effects of high catalytic activity, rapid charge transfer, and robust structural integrity in the MOF-derived ZnO/NiCo2O4/Nb2C MXene composite. Also, the addition of Nb2C MXene significantly enhanced the overall electrical conductivity and accelerated electron transfer kinetics at the electrolyte–electrode interface. These findings demonstrate that the ZnO/NiCo2O4/Nb2C MXene composite is a promising platinum-free counter electrode for advancing DSSCs toward practical commercialization and large-scale energy harvesting applications.

Light harvesting materials are crucial for capturing the sunlight in a device such as a solar cell for better efficiency. In this study, we developed high surface area, submicron-sized TiO2 spheres (MTS) incorporated with anisotropic Au nanoparticles (Au_MTS) to create highly light-absorbing photoanodes for enhanced dye-sensitized solar cell (DSSC) efficiency. The high surface area of MTS (∼125 m2/g) allows for increased dye-loading, while their submicron size (150–300 nm) provides superior light-scattering capabilities for significantly enhancing the photoanode’s light absorption. Furthermore, incorporating of anisotropic Au nanoparticles enables broadband surface plasmon resonance (SPR) coupling, synergistically boosting photon harvesting in the Au_MTS photoanodes. The interconnected tiny TiO2 nanoparticle network in MTS supports charge carrier generation and transport, providing ample sites for dye adsorption and efficient electron pathways. Au_MTS with varying amounts of Au nanoparticles synthesized by a greener microwave-assisted synthesis method and DSSC devices were fabricated and compared with devices made from pristine MTS and P25 nanoparticles. The optimal Au_MTS device, containing ∼1.3 wt% Au nanoparticles, achieved a maximum power conversion efficiency (PCE) of ∼7.7%, representing improvements of ∼40% and ∼60% over pristine MTS (PCE of ∼5.2%) and P25 nanoparticles (PCE of ∼4.71%), respectively. Overall, this work demonstrates the effectiveness of plasmonic mesoporous photoanodes in enhancing DSSC performance through improved photo response, light scattering, and dye loading.

There is a real demand for sustainable lightweight structures because of the growing environmental concerns. One important solution is developing structures through recycled scrap/waste thermoplastic materials. The current work studies the friction stir spot weldability of recycled thermoplastics, which will help to analyze the potential of friction stir-based welding techniques towards developing these sustainable structures. The combined behavior of recycling-welding procedures is investigated, as they may cause degradations; to ensure that the base thermoplastic polymer's chemical, thermal, and mechanical properties are retained. Scrapped milk bottles made from HDPE material are used as a case study. The highest lap-shear load of 1528 N was achieved at the optimum welding conditions of 1600 rpm rotational speed, 1 mm plunge depth, and 60 s dwell time. Fractographic studies (macroscopic and SEM-based) suggested four types of fracture morphologies depending on welding conditions used. The DSC results showed no significant differences in melting temperature and crystalline content of the polymeric material. The TGA tests showed no significant thermal degradations. The FTIR analysis of all the samples (bottle, recycled sheet, weld material) exhibited characteristic HDPE peaks. All these results suggest combined-welding recycling had a minimal impact on the polymeric structure. Thus, friction stir spot welding (FSSW) technique joins recycled thermoplastic scrap/waste materials with high lap-shear load and without any significant polymer degradations.

A series of FexNiy/SA (SA = SiO2-Al2O3) catalysts were synthesized via solvothermal assisted deposition precipitation synthesis method and explored for low-temperature hydrodeoxygenation (HDO) reaction of methyl oleate into n-alkanes and vegetable oils. A comprehensive study on the effects of increasing iron oxide loading in catalyst samples, i.e., Fe1Ni1/SA, Fe3Ni1/SA, Fe5Ni1/SA and Fe7Ni1/SA, on the crystallographic, morphological, textual and surface chemical behavioural were investigated thoroughly using various spectroscopic techniques. The study disclosed excellent surface area, high acidic strength and reducibility of Fe1Ni1/SA catalyst due to the lowest Fe2+ or FeO species. In contrast, higher iron oxide loading leads to the accumulation of Fe2+ ions on the surface with reduced metal acid centres and diminished surface area. The catalytic conversion as well as C17-C18 selectivity in catalytic HDO was also scrutinised with particular reference to Fe2+/Fe3+ ion ratio. The obtained superior catalytic activity and C18 selectivity of Fe1Ni1/SA catalyst are due to the lowest Fe2+/Fe3+ ion ratio. However, the iron oxide loading increased the Fe2+/Fe3+ ion ratio, which ultimately decreased the catalytic activity. Thus, the role of Fe2+ species in the deactivation of catalyst was discussed in detail to establish conversion and selectivity control in the catalytic HDO pathway.

Abstract Developing supercapacitor materials that are both efficient and durable, with high cycle life and specific energy, poses a significant challenge due to issues in electrodes such as volume expansion and electrode degradation that occur over time. This work reports a simple, novel, and cost-effective synthesis method to fabricate high surface area “Iron (Fe) doped TiO2 materials” via the metal-organic framework (MOF) route for supercapacitor application. Morphological analysis revealed a disc-like shaped pattern for pristine TiO2 (PT), and a cuboid form for Fe-doped TiO2 (FeT). The electrochemical investigation of MOF-derived PT and FeT electrode materials demonstrated the superior performance of FeT. Cyclic Voltammetry revealed enhanced electrochemical properties in FeT. Galvanostatic charge-discharge measurements confirmed FeT’s higher energy storage capacity, reaching a maximum specific capacitance of 925 Fg− 1. Long-term cycling tests exhibited excellent stability, with FeT retaining 67% of its initial capacitance after 6000 cycles and showing prolonged self-discharge. Overall, the results underscore the potential of Fe-doped TiO2 for high-performance supercapacitors.

The enduring effort toward stabilizing and improving the efficiency of dye-sensitized solar cells (DSSCs) has stirred the solar research community to follow innovative approaches. Current research centered on electrode materials design, which improves photoanodes' light-harvesting efficiency (LHE). Metal–Organic Frameworks (MOFs) are a new family of materials that can be used as competent materials due to their desirable qualities, including high porosity, flexible synthesis methodology, high thermal and chemical stability, and good light-harvesting capabilities. MOF-derived porous photoanodes can effectively adsorb dye molecules and improve LHE, resulting in high power conversion efficiency (PCE). Doping is a prospective methodology to tune the bandgap and broaden spectral absorption. Hence, a novel and cost-effective synthesis of high surface area transition metal (TM) doped TiO 2 nanocrystals (NCs) via the metal–organic framework route for DSSCs is reported here. Among the TM dopants (i.e., Mn, Fe, Ni), a remarkable PCE of 7.03% was obtained for nickel-doped samples with increased Jsc (14.66 mA/cm 2 ) due to the bandgap narrowing and porous morphology of TiO 2 . The findings were further confirmed using electrochemical impedance spectroscopy (EIS) and dye-desorption experiments. The present study expedites a promising way to enhance the LHE for many innovative optoelectronic devices.

Dye-sensitized solar cells (DSSCs) are low-cost solar energy conversion devices with variable color and transparency advantages. DSSCs' potential power efficiency output, even in diffuse light conditions with consistent performance, allows them to be used in building-integrated photovoltaics (BIPV) window applications. Significantly, the development of bifacial DSSCs is getting significant scientific consideration. Triiodide/iodide (I 3 – /I – ) redox couple-mediated DSSCs require highly effective and stable electrocatalysts for I 3 − reduction to overcome their performance constraints. However, the commonly employed platinum (Pt) cathodes have restrictions on high price and unfavorable durability. Here, we report platinum nanoparticles (Pt NPs) incorporated into multiwalled carbon nanotubes (MWCNT) composites with lower Pt content as an efficient bifacial counter electrode (CE) material for DSSC applications. Pt NPs were homogenously decorated over the MWCNT surfaces using a simple polyol method at relatively low temperatures. CEs fabricated using Pt/MWCNT composites exhibited excellent transparency and power conversion efficiencies (PCE) of 6.92% and 6.09% for front and rear illumination. The results are expected to bring significant advances in bifacial DSSCs for real-world window applications.

Fatty acid-based biomass is one of the most abundant organic carbon sources and has acquired significant attention as a renewable feedstock for producing renewable bio-jet fuel via hydrocatalytic processes.

Industrial heat exchanger applications dealing with highly corrosive fluids demand the use of thermoplastic heat exchangers because of the chemically inert and anti-fouling nature of the thermoplastics. A non-conventional joining framework, based on the friction stir welding (FSW) technique, is used to form high-quality thermoplastic tube-to-tubesheet joints (TTJs). The proposed technique has potential applications for thermoplastic shell-and-tube heat exchangers and piping industries (as flange-to-pipe joints). In this work, the tube and tubesheet materials made of carbon black reinforced high-density polyethylene were used. The effect of different FSW parameters (rotational speed, plunge depth, tube protrusion, dwell time) on the tube pull-out behavior was investigated. The FSW technique showed capabilities at a wide range of operating conditions. The highest load bearing capacity of 517 N was achieved using the FSW process, much higher than adhesive joints. Also, it provides higher extensions at maximum load than adhesive joints, with the highest extension of 5.161 mm. Two FSW cases provided high leak paths of 77% and 58% remaining sheet thickness (greater than tube thickness) along with high load bearing capacity and corresponding extensions. The macroscopic and SEM-based fractographic studies illustrated three types of failure behavior: ductile, brittle, or mixed depending on the FSW process conditions. The DSC results showed no significant crystallinity changes in the weld material. The TGA results showed no significant thermal degradation occurring in the weld material. Further, the FTIR analysis indicated possible oxidation of the weld material. The capability to form TTJs with high leak path, high load bearing capacity, and no significant material degradations makes the FSW technique suitable for thermoplastic shell-and-tube heat exchanger applications.

The drawback of tungsten inert gas welded tube-to-tubesheet joints is shortened leak path between transfer fluids. In this work, solid-state friction stir welding is performed for investigating the combined effects of tube protrusions and radial clearances on tube-to-tubesheet joints made of AA 6061-T6 tube and AA 6063-T6 tubesheet. Joints with complete fusion over the entire clearance resulting in maximum leak paths are produced by the friction stir welding process. The average leak path of friction stir welded joints with 4.48 mm was higher than the 2.90 mm leak path of tungsten inert gas welded joints. The optimal tube pull-out load of 10,073.37 N using friction stir welding with 2 mm protrusion and 0 mm radial clearance is close to the maximum tube pull-out load of 10,081.84 N obtained using the tungsten inert gas welding process. Friction stir welding with protrusion was proven as an effective technique for producing tube-to-tubesheet joints with maximum leak path. [GRAPHICS] .

A series of ZnO–Ti 3 C 2 T x catalysts was studied first time for the catalytic hydrodeoxygenation (HDO) reaction. The catalyst exhibited complete conversion and >90% selectivity for octadecane (C-18) with 5-cycle recyclability.

In recent years, there has been much focus on how the structure and morphology of CoMn2O4 materials influence their electrochemical performance. Herein we introduce a KOH-surfactant agent to form a hexagonal like-CoMn2O4 via hydrothermal. The X-ray Rietveld refinement evidenced that spinel CoMn2O4 with the tetragonal structured I 41/amd phase. Further, the chemical environment of this phase is identified using various techniques. Surface morphology studies revealed hexagonal-like features. Owing to its features, the material delivers an excellent capacitance of 638.8 F/g. CoMn2O4 also shows attained columbic efficiency of 81% and retains a capacitance of 85% after 4000 charge-discharge cycles. The excellent cyclic stability and high performance are achieved due to the more active sites and convenient electronic transference route for the ions through an electrochemical process. The symmetrical two-electrode assembly has also been fabricated. Hence, we believed that the surfactant-KOH mediated hexagonal-like-CoMn2O4 material should enhance the supercapacitor properties.

Herein, we report a simple hydrothermal synthesis of ZnO-Ti3C2 MXene nanocomposites with a varying wt % of ZnO to exploit the synergistic effect of 2D layer structured Ti3C2 and semiconductor ZnO for photocatalysis and electrocatalysis applications. A systematic study on the efficiency of ZnO-Ti3C2 nanocomposites toward the degradation of organic pollutants (dyes and pharmaceuticals) and the hydrogen evolution reaction (HER) is demonstrated. Among the developed nanohybrid catalysts, the ZnOTi3C2 composite with 10 wt % ZnO (MXZnO-10) showed the highest photodegradation efficiency of 76.4% within 10 min of the reaction and 99.2% in 60 min for methylene blue (MB) dye. The synergistic interactions between 2D layered Ti3C2 and ZnO improved the lifetime of electrons and holes by reducing the recombination rate. The uncombined electrons and holes facilitated the effective degradation of the MB dye. The ZnO-Ti3C2 nanocomposite with S wt % ZnO (MXZnO-S) showed excellent HER performance and exhibited an overpotential of 495 mV at 10 mA/cm(2) with a Tafel slope of 108 mV/dec. This work widens the application range of transition metal oxide-MXene composites, providing potential substitute materials for photocatalysis and electrocatalysis applications.

Cubic spinel LiMn2O4 (LMO) are promising electrode materials for advanced technological devices owing to their rich electrochemical properties. Here, a series of Gd3+-doped LiMn2O4 were synthesized using a simple one-step sol-gel synthesis, and a systematized study on the effect of increasing Gd3+ concentration on magnetic properties is conferred. The Raman and density functional theory (DFT) calculations of the synthesized materials were correlated with the magnetic properties; we observed a high coercivity value for the doped LMO compared to pristine LMO, which scales down from 0.57T to 0.14T with an increase in Gd concentration. The samples exhibited paramagnetic (at 300K) to antiferromagnetic (at 5K) transition and variation in the magnetic moment due to the replacement of Mn+2 or Mn+3 ion by Gd+3 ion from the octahedral 16d lattice site. The observed phase transitions in the hysteresis curve below the Neel temperature (TN) at 5K are found to be due to the superexchange mechanism.

Improvement of light-harvesting efficiency using the localized surface plasmon resonance (LSPR) from the metals nanoparticles (MNPs) is a promising approach to boost the efficiency of the solar energy conversion systems. To attain the narrowband SPR, synthesis of the monodisperse MNPs with particular shapes and sizes is cumbersome and has great importance for (surface-enhanced Raman spectroscopy) SERS application. Contrary, broadband SPR is prominent for solar cell applications to absorb maximum sunlight from the solar spectrum. Incorporating polydisperse MNPs of mixed shapes and sizes is a unique approach to realizing the broadband SPR for solar cell application. However, the synthesis of polydisperse MNPs with good reproducibility is challenging. To address this issue, we report facile one-pot microwave synthesis of mixed shapes and sizes of Au nanoparticles (Au-Mx), possessing broadband SPR with decent reproducibility. Microwave-assisted uniform heating provides the control over the reaction parameter to produce identical SPR. Further, the light-harvesting ability of the Au-Mx is demonstrated by incorporating -1% of Au-Mx in photoanode while fabricating the dye-sensitized solar cells (DSSCs). The photoconversion efficiency (PCE) of the Au-Mx loaded DSSCs improved by -30% compared to the reference devices, indicating the effective utilization of broadband SPR for efficient charge generation in plas-monic devices.

Heteroatom-doped carbons are emerging candidates for metal-free catalysis, photocatalysis, and pollutant removal. Herein, we report the synthesis of N-doped solid (CS) and hollow carbon spheres (CNB) via a modified Stöber’s method. TEM, Raman, and XPS characterization techniques demonstrated a well-constructed N-doped sp2/sp3 hybridized carbons scaffold. Both CNB and CS nanospherical carbons have shown a high surface area of 360 and 400 m2/g, respectively, making them ideal candidates for the adsorption of pharmaceutical pollutants (ciprofloxacin and ibuprofen) and heavy metals (Pb and Cr) from wastewater. These materials have good interfacial interaction with the adsorbate and generate the proper medium to facilitate fast and efficient remediation. The highest surface adsorption (96% in 30 min) was observed for ibuprofen by CS. Interestingly, CNB was more selective for heavy metals at lower concentrations, while CS showed high surface adsorption at higher concentrations.

This systematic study includes physical–chemical characterisation of nanomaterials, arsenic adsorption assays, adsorption mechanism proposal, and acute toxicity assays with Daphnia magna.

Lithium-free metal batteries are currently emerging as a viable substitute for the existing Li-ion battery technology, especially for large-scale energy storage, ease of problems with lithium availability, high cost, and safety concerns. However, the economic benefits of lithium-free batteries, which are often mentioned, have not been studied in detail until recently. This paper aims to bridge the gap between academics and industry by advocating the best practices for measuring performance and proposing recommendations concerning essential parameters, including capacity, cyclability, Coulombic efficiency, and electrolyte consumption in novel lithium-free batteries. Here, the monovalent, divalent, and multivalent lithium-free metal batteries are investigated. Finally, the technology roadmap of these battery technologies and their current applications, commercialization, and future technologies are discussed to open a window for promoting the commercial application of lithium-free metal batteries.