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Modulation of the structure, composition, and morphology through a simple refinement of the synthetic parameters is central to obtaining signature catalytic properties, enabling an understanding of the underlying growth and reaction mechanisms. In this study, a bismuth vanadate (BiVO4) model photocatalyst with several nanostructures (including pillar-like, dendrites, and microgranules) was fabricated by simple hydrothermal, solvothermal, and solid-state reaction (SSR) methods. As the solvothermal reaction temperature was increased, the tetragonal phase transformed into a monoclinic phase, and the inorganic nuclei interacted, self-assembled, and grew continuously to yield a well-defined architecture indicating the critical role of temperature in stabilizing the crystal structure and surface atomic features principally in an ethanol/water mixture. In contrast, conventional hydrothermal synthesis (only water as a solvent) resulted in single-phase BiVO4 pillars enriched with rough surfaces, sharp edges, and porous structures. The growth mechanism of the BiVO4 dendrites was investigated by the morphological evolutions from different reaction products obtained under different reaction conditions. BiVO4 has a bandgap energy in the visible spectral range (2.50–2.27 eV). Hence, BiVO4 architectures with exclusively controlled surfaces and crystal structures can be used as efficient photocatalysts to remove organic pollutants (methylene blue dye) in water. The solvothermally prepared BVO-SLR'24 with a mixed-phase (monoclinic and tetragonal zircon) structure exhibited superior photocatalytic activities for the decomposition of organic contaminants, which may be due to the unique connectivity between crystals, accelerated electron transfer, and heterojunction formation, compared to BiVO4 prepared with pure phase pillars and microgranules. This work highlights the significance of synthesis methodology and microstructural modification with the photophysical properties to reinvigorate the conventional design of visible-light-driven (VLD) photocatalysts. [ABSTRACT FROM AUTHOR]

Lignin nanoparticles (LNPs) have gained great interest as a promising renewable nanomaterial toward value-added applications. This work investigated solution chemistry and particle–particle interaction force in the LNP formation aiming at a facile technique to balance amphiphilic properties of lignin for size-controlled synthesis. By facilely tuning solution chemistry, lignin with different amphiphilic properties can form the nanoparticles with 57–262 nm and dispersity index (Đ) less than 0.2 at an initial lignin concentration of 10–80 g L−1. A numerical estimation of particle size was established with Derjaguin–Landau–Verwey–Overbeek's (DLVO) theory and population balance equation (PBE) to evaluate the interaction energy of particles as the function of solution chemistry and lignin properties. In the developed DLVO–PBE model, lignin properties such as molecular weights and content of functional groups are closely related to the repulsive energy calculation in the particle collision and further determine the assembly patterns. The model can be applied to lignin with varied properties with high prediction accuracy, especially in the DLVO forces-driven aggregation. It also suggests that solvated lignin chains can involve the uneven electrostatic force field and non-DLVO forces leading to a broad/multi-modal size distribution. Overall, the combination of experimental and theoretical investigations provides new insights into assembly mechanisms of lignin molecules involved in the formation of nano-/submicron particles. [ABSTRACT FROM AUTHOR]

A new amperometric biosensor for hydrogen peroxide (H2O2) and superoxide anion (SO) has been developed. The biosensor developed uses cytochrome c (Cyt c) modified glassy carbon electrodes coupled with electrochemically reduced graphene oxide (ErGO). To immobilize Cyt c, the “one step” electrochemical deposition of vertically aligned and ErGO (VAErGO) has been performed by using a pulse reverse technique, thus resulting in a very simple and efficient system. The well-established vertical alignment of ErGO was confirmed by atomic force microscopy and the electrochemical characteristics of the biosensor were investigated by cyclic voltammetric, electrochemical impedance spectroscopy and amperometric techniques. The surface coverage (Γ) of immobilized Cyt c was effectively increased by the vertical alignment of ErGO and found to be 1.03 × 10−10 mol cm−2. The direct electron transfer property of Cyt c was also improved by VAErGO and the heterogeneous electron transfer rate constant (ket) was estimated to be 6.40 s−1. To detect H2O2 and SO, amperometric measurements were carried out at different operating potentials (0.0 V vs. Ag/AgCl for H2O2 and +0.2 V for SO). The sensitivity and detection limit for H2O2 were found to be 46.3 μA mM−1 cm−2 and 2.3 μM, and for SO were found to be 32.1 μM nA−1 cm−2 and 6.84 nM s−1, respectively. Additionally, the designed biosensor exhibited strong anti-interference ability and satisfactory reproducibility. [ABSTRACT FROM AUTHOR]

The position at which conjugated side chains were fluorinated, the meta- or ortho-position in phenyl side chains, was varied to investigate the positional effects of fluorination on the energy levels, crystalline ordering, and photovoltaic properties of the polymers. The fluorine in the ortho-position achieved a lower HOMO energy level than that in the meta-position, but reduced the chain rigidity. [ABSTRACT FROM AUTHOR]

Hole transporting materials (HTMs) with high charge carrier mobilities and receptive functionalities have gained significant attention recently due to their direct effect on boosting the efficiency and lifetime of perovskite solar cells (PVSCs). Herein, two new simple small molecular diketopyrrolopyrrole-based HTMs with different central π-bridges (thieno[3,2-b]thiophene (DPP-TT), and dithieno[3,2-b : 2′,3′-d] thiophene (DPP-DTT)) were synthesized via a facile molecular engineering approach. Both small molecules exhibited strong absorption between 500 and 750 nm and an optical bandgap of ∼1.48 and 1.52 eV; however, their crystalline natures were significantly different, resulting in marked differences in their coating ability and PVSC performances. Thus, optimized DPP-TT-based PVSC devices with a lithium (bis(trifluoromethanesulfonyl)imide) dopant demonstrated a maximum PCE of 15.57% with superior energy level matching and an optimal trade-off between aggregation and processability, resulting in effective perovskite layer passivation via high surface coverage and suppression of charge recombination. In comparison, DPP-DTT had a slightly lower PCE of 14.49%, attributed to its poor film quality caused by its high aggregation tendency. Additionally, these HTMs delivered superior stability owing to superior hydrophobic characteristics. These findings provide valuable insight into the design of new HTMs with varying central π-bridge, which is a simple and effective approach. [ABSTRACT FROM AUTHOR]

We report the synthetic methodology for silver nanorings with controlled nanoscale morphology. The morphology of Ag nanorings was kinetically controlled by electrochemical potential tuning of Ag deposition using halide counter-ions, which resulted in concentric PtAu@Ag nanorings (i.e., Ag homogeneously wrapped around the Pt nanorings) and eccentric PtAu@Ag nanorings (i.e., Ag selectively deposited at the inner boundary of the Pt nanorings). The resulting high quality of each Ag nanoring allowed us to systematically investigate their corresponding localized surface plasmon resonance (LSPR) profiles as a function of their geometrical parameters. Additionally, we evaluated the application of the samples as surface-enhanced Raman spectroscopy (SERS) substrates composed of 2D monolayers of varied compositions of Ag and Au nanorings, which showed a different extent of enhancement depending on the adsorption characteristics of the analytes. [ABSTRACT FROM AUTHOR]

A new type of disposable flexible sensor for hydrogen peroxide (H2O2) detection was developed by in situ synthesis of copper–ruthenium bimetallic nanoparticles on a laser-induced graphene surface (Cu–Ru/LIG). The approach produced Cu–Ru/LIG via a solid phase transfer mechanism which loaded the metal precursor onto LIG, followed by laser scribing without demanding chemical vapor deposition or solution-based reactions. Cu–Ru/LIG showed a high electrocatalytic response toward H2O2 reduction at −0.4 V vs. Ag/AgCl. The sensor also showed good selectivity and reproducibility. This method provides an alternative route to easily synthesize various catalysts on conductive substrates for sensor applications. [ABSTRACT FROM AUTHOR]

A new approach based on differential pulse voltammetry (DPV) was developed for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) using a modified glassy carbon electrode (GCE). The sensor was constructed by a simple “one-step” technique, wherein de-bundled single-walled carbon nanotubes (SWCNTs) were drop-cast onto the GCE. Without de-bundling, the SWCNTs were poorly dispersed in aqueous solution and were ineffective for the one-step procedure. De-bundling of the SWCNTs was achieved using a small amount (0.1 wt%) of the synthesized polymer dispersant, sulfonated poly(ether sulfone) (SPES); the de-bundled SWCNTs had a high aspect ratio (length = 2.5 ± 1.0 μm; height = 2 ± 1 nm, as determined using transmission electron microscopy and atomic force microscopy). The de-bundled SWCNTs also led to enhanced electrocatalytic activity and selectivity of the modified sensor for the simultaneous determination of AA, DA, and UA in DPV measurements: the peak-to-peak separation values were 221, 119, and 340 mV (vs. Ag/AgCl) for DA–AA, UA–DA, and AA–UA, respectively. The dynamic linear ranges for AA, DA, and UA were 0.2–1.6 mM, 5.0–50 μM, and 5.0–60 μM, and the detection limits were 10.6 μM, 15 nM, and 113 nM (S/N = 3), respectively. The analytical performance of the developed sensor was demonstrated in the determination of AA and DA in commercial pharmaceutical samples (vitamin C tablets and DA injection). The characteristics of the modified sensor make it promising for the individual or simultaneous determination of AA, DA, and UA. [ABSTRACT FROM AUTHOR]

Correction for 'Structure–property relationships of diketopyrrolopyrrole- and thienoacene-based A–D–A type hole transport materials for efficient perovskite solar cells' by Gururaj P. Kini et al., New J. Chem., 2022, DOI: https://doi.org/10.1039/d2nj00294a. [ABSTRACT FROM AUTHOR]