National Nanotechnology Center

Nickel titanate (NiTiO3) is a promising pseudocapacitive electrode material; however, its electrochemical performance is limited by low electrical conductivity and slow ion transport. In this work, a solvent-free solid-state NaBH4 reduction strategy is developed to introduce oxygen vacancies (OVs) into NiTiO3, producing reduced NiTiO3 (R-NTO) with a three-dimensional (3D) cauliflower-like morphology and controllable defect density. The optimized R300-NTO-1.2 electrode delivers a 207.8% increase in specific capacitance (505 F g–1) compared with pristine NiTiO3, along with improved wettability and stable cycling performance (89.2% retention after 10,000 cycles), owing to its OV-rich structure and hierarchical porosity. By coupling R300-NTO-1.2 with reduced crumpled graphene oxide (rCGO) as the negative electrode, a high-performance asymmetric supercapacitor (ASC) is constructed, combining Faradaic charge storage at the positive electrode with an electric double-layer capacitance at the negative electrode. Benefiting from effective electrode potential matching, the R300-NTO-1.2//rCGO-ASC operates stably over a 2.0 V voltage window, achieving an energy density of 44.0 Wh kg–1 at 1000 W kg–1 and retaining 34.2 Wh kg–1 at 6000 W kg–1, together with 94.9% capacitance retention and 100% Coulombic efficiency. This study demonstrates that solid-state NaBH4-induced OV engineering, when combined with a structurally robust carbon electrode, offers an effective and scalable approach for developing high-energy, long-life aqueous ASCs.

This study benchmarks two nanocellulose (NC) production architectures: sulfuric-acid hydrolysis of pineapple peel biomass to obtain hydrolyzed nanocellulose (HNC) and microbial biosynthesis of bacterial nanocellulose (BNC) by Rhizobium leguminosarum biovar trifolii in defined media. HNC and BNC were characterized by SEM, FTIR, AFM, and ζ-potential, and the routes were compared using a sustainability-focused multicriteria framework. The Visual Integration of Multicriteria Evaluation (VIME) (radar chart + weighted decision matrix) yielded a higher overall score for BNC (66) than HNC (51), driven primarily by lower downstream washing/neutralization water demand (~0.3 L vs. ~14 L per batch), fewer purification stages (~2 vs. ~5), and lower waste hazard. In contrast, HNC performed better in calendar time (~7 vs. ~18 days). AFM revealed route-dependent morphologies: BNC formed a homogeneous nanofiber network (37 ± 9 nm), while HNC formed heterogeneous lamellar fragments (70 ± 12 nm). Route-specific yields were 3.15% (w/w, dry biomass basis) for HNC and 1.065 g/L (culture-volume basis) for BNC. Although a full ISO-compliant Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) are beyond the scope of this laboratory-scale study, the defined system boundaries and reported process inventories provide an LCA/TEA-ready template for future mass- and cost-balanced comparisons.

The development of bifunctional electrocatalysts capable of steering CO2 reduction toward selective C1 products under mild conditions remains central to advancing next-generation electrochemical technologies. Here, we demonstrate that stabilization of Cu+ species by N-doped carbon derived from tea leaves (TL9) enables highly selective and durable CO2 electroreduction to CO and formate. Uniformly dispersed Cu2O nanoparticles supported on TL9 exhibit strong metal–support interactions and form stable Cu–Nx coordination that preserves the active Cu+/Cu0 interface during operation. Structural, spectroscopic, and electrochemical analyses reveal that this tailored interface suppresses Cu agglomeration and hydrogen evolution, promoting efficient two-electron transfer pathways. The optimized TL9/Cu-40% catalyst achieves faradaic efficiencies approaching 90% for CO and formate at −0.6 V vs. RHE and maintains over 60% selectivity after 24 h of continuous operation. These findings highlight how defect-engineered carbon supports can precisely regulate Cu oxidation states to enhance efficiency, selectivity, and stability—offering a robust design principle for bifunctional catalysts that couple renewable electricity with CO2 valorization.

Demand for batteries continues to increase in line with the growth of electric vehicles, while the availability of lithium in nature is limited. One alternative is the use of renewable natural materials, such as coconut shells, to produce functional carbon materials. This study aims to synthesize graphene-like carbon (GLC) from coconut shells using pyrolysis and sonication methods. The process was carried out through drying at 150–200 °C and pyrolysis at 700 °C. XRD characterization showed main peaks at 2θ ≈ 23.11° and 43.75° (150 °C/700 °C), and 23.15° and 43.38° (200 °C/700 °C), with an interlayer spacing of 0.35 nm and a shift in the C (002) peak from pure graphite, indicating the formation of nanosized graphene layers. FTIR analysis confirmed the presence of O–H, aromatic C=C, C=O, and C–O groups, indicating a hexagonal carbon framework with oxygen functionality on the surface. The Raman spectrum showed ID/IG ratios of 0.84 and 0.83, indicating structural disorder while still consistent with graphene-like characteristics. Conductivity tests showed relatively stable electrical conductivity with gradual electron energy loss at small current increases, allowing better control of electron mobility.

A novel analytical method is proposed that integrates monolithic sorbent micro-solid-phase extraction (µ-SPE) with an anodized screen-printed graphene electrode for the determination of serotonin (SER). Monolithic sorbent µ-SPE offers a straightforward and efficient pretreatment method for removing of interfering substances, thereby enhancing the selectivity of SER analysis before being coupled with an electrochemical sensor. Under optimal conditions, the integration of monolithic sorbent µ-SPE with the electrochemical sensor provided a broad linear range of 50-1500 nM for SER detection, with detection and quantification limits of 4.78 and 15.94 nM, respectively. The developed sensor exhibited excellent reproducibility (RSD < 10%) and good stability over a period of 6 months. Furthermore, the proposed method can detect SER even in the presence of ascorbic acid and uric acid at their normal levels in human biological fluids. This method was successfully applied to determine SER levels in real urine samples with an acceptable recovery range of 93.76%-124.14%. The analytical results derived from the developed methodology are strongly correlated with those obtained using the standard high-performance liquid chromatography method.

Viscosity variations within cellular microenvironments are closely associated with pathological states such as cancer, motivating the development of molecular probes that integrate environmental sensing with therapeutic function. Here, we report two anthracene-fused heptamethine cyanine molecular rotors, ASCy7 (asymmetric) and SCy7 (symmetric), designed as heavy-atom-free near-infrared (NIR) materials for combined viscosity sensing and imaging-guided photodynamic therapy (PDT). Anthracene π-extension enhances intramolecular charge transfer and spin-orbit coupling, thereby promoting intersystem crossing and efficient singlet oxygen generation under 850 nm irradiation. Both probes exhibit strong viscosity-dependent fluorescence via the twisted intramolecular charge transfer (TICT) mechanism and show selective mitochondrial localization in HepG2 cells. Upon NIR activation, ASCy7 and SCy7 induce reactive oxygen species-mediated apoptosis with IC50 values as low as 0.39 µM, while maintaining excellent dark biocompatibility. This work establishes π-extension engineering as an effective materials design strategy to integrate environmental responsiveness and photodynamic activity within a single NIR cyanine platform for cancer theranostics.