Phosphorus and sulfur co-doped nickel molybdate with rich-oxygen vacancies for efficient water splitting.

The rational design of high-performance electrocatalysts is essential for promoting the industrialization of electrocatalytic water-splitting technology. Herein, phosphorus and sulfur co-doped nickel molybdate with rich-oxygen vacancies (P, S-NiMoO4) was prepared as an efficient bifunctional self-supporting water-splitting catalyst from the perspective of enhancing the conductivity and optimizing the electronic configurations. The incorporation of P, S and oxygen vacancies greatly enhances the conductivity and charge-transfer efficiency of NiMoO4. Additionally, P and S can serve as proton carriers and electron acceptors to enhance the catalytic activity by accelerating proton activation and high-valent metal generation in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As expected, P, S-NiMoO4 demonstrates efficient bifunctional catalytic activity with an overpotential of only 31/206 mV at 10 mA cm-2 for HER/OER in 1 M KOH. Meantime, the electrolyzer assembled with P, S-NiMoO4 as electrodes requires a voltage of only 1.55 V to achieve a water-splitting current density of 50 mA cm-2 along with good stability over 110 h. This work puts forward a novel approach based on elemental doping and vacancy engineering for the design of effective and enduring catalysts for water splitting.

Facilitating charge transfer via a Semi-Coherent Fe(PO3)2-Co2P2O7 heterointerface for highly efficient Zn-Air batteries.

Developing reversible oxygen electrodes for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for achieving high-performance rechargeable Zn-air batteries (ZABs). This study introduced an nitrogen-doped carbon confined with a semi-coherent Fe(PO3)2-Co2P2O7 heterojunction for bifunctional oxygen electrocatalysis. This nanocomposite yielded an ORR half-wave potential of 0.908 V and an OER overpotential of 291 mV at 10 mA/cm2. ZABs incorporating this catalyst yielded impressive performance, including a peak power density of 203 mW/cm2, a specific capacity of 737 mAh/gZn, and promoted stability. Both experimental and theoretical simulations demonstrated that the unique electric field between Fe(PO3)2 and Co2P2O7 promoted efficient charge transport across the heterointerface. This interaction likely modulated the d-band center of the heterojunction, expedite the desorption of oxygen intermediates, thus improving oxygen catalysis and, consequently, ZAB performance. This work illustrates a significant design principle for creating efficient bifunctional catalysts in energy conversion technologies.

Selective Segregation of Thermo-Responsive Microgels via Microfluidic Technology.

Separation of equally sized particles distinguished solely by material properties remains still a very challenging task. Here a simple separation of differently charged, thermo-responsive polymeric particles (for example microgels) but equal in size, via the combination of pressure-driven microfluidic flow and precise temperature control is proposed. The separation principle relies on forcing thermo-responsive microgels to undergo the volume phase transition during heating and therefore changing its size and correspondingly the change in drift along a pressure driven shear flow. Different thermo-responsive particle types such as different grades of ionizable groups inside the polymer matrix have different temperature regions of volume phase transition temperature (VPTT). This enables selective control of collapsed versus swollen microgels, and accordingly, this physical principle provides a simple method for fractioning a binary mixture with at least one thermo-responsive particle, which is achieved by elution times in the sense of particle chromatography. The concepts are visualized in experimental studies, with an intend to improve the purification strategy of the broad distribution of charged microgels into fractioning to more narrow distribution microgels distinguished solely by slight differences in net charge.

SnF2-Catalyzed Lithiophilic-Lithiophobic Gradient Interface for High-Rate PEO-based All-Solid-State Batteries.

Polyethylene oxide (PEO)-based all solid-state lithium metal batteries (ASSLMBs) are strongly hindered by the fast dendrite growth at the Li metal/electrolyte interface, especially under large rates. The above issue stems from the suboptimal interfacial chemistry and poor Li+ transport kinetics during cycling. Herein, a SnF2-catalyzed lithiophilic-lithiophobic gradient solid electrolyte interphase (SCG-SEI) of LixSny/LiF-Li2O is in-situ formed. The superior ionic LiF-Li2O rich upper layer (17.1 nm) possesses high interfacial energy and fast Li+ diffusion channels, wherein lithiophilic LixSny alloy layer (8.4 nm) could highly reduce the nucleation overpotential with lower diffusion barrier and promote rapid electron transportation for reversible Li+ plating/stripping. Simultaneously, the insoluble SnF2-coordinated PEO promotes the rapid Li+ ion transport in the bulk phase. As a result, an over 46.7 and 3.5 times improvements for lifespan and critical current density of symmetrical cells are achieved, respectively. Furthermore, LiFePO4-based ASSLMBs deliver a recorded cycling performance at 5 C (over 1000 cycles with a capacity retention of 80.0%). More importantly, impressive electrochemical performances and safety tests with LiNi0.8Mn0.1Co0.1O2 and pouch cell with LiFePO4, even under extreme conditions (i.e., 100 ℃), are also demonstrated, reconfirmed the importance of lithiophilic-lithiophobic gradient interfacial chemistry in the design of high-rate ASSLMBs for safety applications.

Lattice Manipulation with Di-Tertiary Ammonium Spacer in Bismuth Bromide Perovskite Directs Efficient Charge Transport and Suppressed Ion Migration for Photodetector Applications.

Bismuth halide hybrid perovskites have emerged as promising alternatives to their lead halide homologs because of high chemical stability, low toxicity, and structural diversity. However, their advancements in optoelectronic field are plagued with poor charge transport, due to considerable microstrain triggered by bulky spacer. Herein, the di-tertiary ammonium spacer (N,N,N',N'-tetramethyl-1,4-butanediammonium, TMBD) is explored to direct stable 1D bismuth bromide lattice structure with relaxed microstrain. Compared to the primary pentamethylenediamine (PD)2+, the (TMBD)2+ adopting alternating alignment enables a unique H-bonds mode to distort the configuration of inorganic layers to form corner-sharing [BiBr5] near-regular chains with narrower bandgap, lower exciton binding energy, and reduced carrier-lattice interactions, thereby facilitating charge-carrier transport. Moreover, the (TMBD)2+ spacers largely suppress ion migration in perovskite lattice, as substantiated by the experimental and theoretical investigations. Consequently, (TMBD)BiBr5 single crystal photodetector delivers a 185-fold increase in current on/off ratio with respect to (PD)BiBr5 under white light irradiation, considerable responsivity (≈82.97 mA W-1), detectivity (≈8.06 ×1011 Jones) under weak light (0.02 mW cm-2) irradiation, in the top rank of the reported hybrid bismuth halide perovskites. This finding offers novel design criterion for high-performance lead-free perovskites.

Triple Templates Directed Synthesis of Nitrogen-Doped Hierarchically Porous Carbons from Pyridine Rich Monomer as Efficient and Reversible SO2 Adsorbents.

Herein, a variety of 2,6-diaminopyridine (DAP) derived nitrogen-doped hierarchically porous carbon (DAP-NHPC-T) prepared from carbonization-induced structure transformation of DAP-Zn-SiO2-P123 nanocomposites are reported, which are facilely prepared from solvent-free co-assembly of block copolymer templates P123 with pyridine-rich monomer of DAP, Zn(NO3)2 and tetramethoxysilane. In the pyrolysis process, P123 and SiO2 templates promote the formation of mesoporous and supermicroporous structures in the DAP-NHPC-T, while high-temperature volatilization of Zn contributed to generation of micropores. The DAP-NHPC-T possess large BET surface areas (≈956-1126 m2 g-1), hierarchical porosity with micro-supermicro-mesoporous feature and high nitrogen contents (≈10.44-5.99 at%) with tunable density of pyridine-based nitrogen sites (≈5.99-3.32 at%), exhibiting good accessibility and reinforced interaction with SO2. Consequently, the DAP-NHPC-T show high SO2 capacity (14.7 mmol g-1, 25 °C and 1.0 bar) and SO2/CO2/N2 IAST selectivities, extraordinary dynamic breakthrough separation efficiency and cycling stability, far beyond any other reported nitrogen-doped metal-free carbon. As verified by in situ spectroscopy and theoretical calculations, the pyridine-based nitrogen sites of the DAP-NHPC-T boost SO2 adsorption via the unique charge transfer, the adsorption mechanism and reaction model have been finally clarified.

D-π-A type fluorescent dyes: Effect of π-bridge units on optical and G4 DNA binding properties.

Fluorescent solvatochromic dyes that are sensitive to the nature of local microenvironmental, have been explored as probes in applications ranging from the imaging biomolecules to understanding of basic biomolecule functions. To expand the scope of fluorescent solvatochromic dyes for G-quadruplex (G4) DNA structures, and to illustrate the relationship between structure and properties, three newly designed D-π-A type fluorescent dyes were synthesized by introducing diarylimidazole to carbazole skeleton linked to benzene, furan or thiophene π-conjugated bridge and connected with pyridinium acceptor, respectively. Their structural characteristics, optical properties, and G4 DNA binding properties were discussed in detail. In general, the incorporation of furan and thiophene as π-conjugated bridges leads the better conjugation and molecular coplanarity with more efficient intramolecular charge transfer (ICT) effect compared with benzene bridge. The fluorescence intensities induced upon interaction were found that TP-6 with thiophene π-conjugated bridge had the strongest response toward G4 DNAs. In addition, the application of this dye as a fluorescent agent for living cell imaging was also demonstrated.

Size matters: Altering antigen specific immune tolerance by tuning size of particles.

Precisely co-delivering antigens and immunosuppressants via nano/microcarriers to antigen-presenting cells (APCs) to induce antigen-specific immune tolerance represents a highly promising strategy for treating or preventing autoimmune diseases. The physicochemical properties of nano/microcarriers play a pivotal role in regulating immune function, with particle size and surface charge emerging as crucial parameters. In particular, very few studies have investigated micron-scale carriers of antigens. Herein, various nanoparticles and microparticles (NPs/MPs) with diverse particle sizes (ranging from 200 nm to 5 µm) and surface charges were prepared. Antigen peptides (MOG35-55) and immunosuppressants were encapsulated in these particles to induce antigen-specific immune tolerance. Two emulsifiers, PVA and PEMA, were employed to confer different surface charges to the NPs/MPs. The in vitro and in vivo studies demonstrated that NP/MP-PEMA could induce immune tolerance earlier than NP/MP-PVA and that NP/MP-PVA could induce immune tolerance more slowly and sustainably, indicating that highly negatively charged particles can induce immune tolerance more rapidly. Among the different sizes and charged particles tested, 200-nm-NP-PVA and 3-µm-MP-PEMA induced the greatest immune tolerance. In addition, the combination of NPs with MPs can further improve the induction of immune tolerance. In particular, combining 200 nm-NP-PVA with 3 µm-MP-PEMA or combining 500 nm-NP-PEMA with 3 µm-MP-PVA had optimal therapeutic efficacy. This study offers a new perspective for treating diseases by combining NPs with MPs and applying different emulsifiers to prepare NPs and MPs.

The third-order nonlinear optical responses of zinc porphyrin oligomers: Cycles vs linear chains.

Porphyrins are widely used as potential nonlinear optical (NLO) materials because of their highly delocalized π electrons and feasible synthesis and functionalization with broad biological applications. A variety of linear and cyclic porphyrin derivatives have been synthesized, and the correlation between their structures and NLO properties awaits being disclosed. In this work, the electronic structures and third-order NLO properties of linear and cyclic butadiyne-linked zinc porphyrin oligomers have been studied by quantum chemical methods and sum-over-states model. The static second hyperpolarizability (<γ0>) increases exponentially with the number of zinc porphyrin units ([<γ0>n] = 0.67[<γ0>1]n2.63, n = 2 âˆ¼ 6) in linear π-conjugated oligomers, and the <γ0> of the linear hexamer is about 74 times that of the monomer. Such enhancement of <γ0> in linear oligomers originates from closely-lying frontier molecular orbitals available for low energy electron excitations and strong charge transfer-based excitations across porphyrins. The <γ0>s of cyclic porphyrins are lower than that of the linear hexamer, though the interaction between the ring and the ligand enhances the <γ0> of some cyclic zinc porphyrin complexes. The large two-photon absorption cross sections confer on these zinc porphyrin derivatives excellent candidates for two-photon absorption applications.

Double-Layer Electronegative Structure-Based Triboelectric Nanogenerator for Enhanced Performance Using Combined Effect of Enhanced Charge Generation and Improved Charge Trapping.

The performance of a triboelectric nanogenerator (TENG) device depends on the amount of generated surface charges during triboelectrification and the retention of surface charges. Here, we present the fabrication of a double-layer nanocomposite structure for the electronegative layer in a TENG, which resulted in the enhanced generation of surface charges and retention of generated charges. The double-layer structure is a stack of two different nanocomposite layers, in which the top layer is a nanocomposite of PVDF and MXene and the bottom layer is a nanocomposite layer of PDMS and NaNbO3 nanoparticles. The use of the double-layer structure for the electronegative layer enhanced the generated voltage to 150 V and the current to 4.3 µA, resulting in an output power density of 134 µW/cm2, which is ∼5.8 times higher compared to the performance of a TENG with a single PVDF electronegative layer. Through systematic Kelvin probe force microscopy measurements, it is shown that the introduction of a highly electronegative MXene in the PVDF matrix improved the electron affinity of the friction layer, resulting in enhanced charge generation during contact electrification. The introduction of NaNbO3 ferroelectric nanoparticles in the PDMS matrix is shown to result in enhanced internal polarization and increased trap sites, resulting in the retention of generated surface charges for longer durations. The combined effect of the two layers resulted in a substantial improvement in TENG performance. The application of the TENG device in wireless communication for signal transfer is also presented.

Efficient CdIn2S4/MgIn2S4 heterojunction for ultrasensitive detection of lung cancer marker neuron-specific enolase.

In this work, a photoelectrochemical (PEC) immunosensor was constructed for the ultrasensitive detection of lung cancer marker neuron-specific enolase (NSE) based on a microflower-like heterojunction of cadmium indium sulfide and magnesium indium sulfide (CdIn2S4/MgIn2S4, CMIS) as photoactive material. Specifically, the well-matched energy level structure and narrow energy level gradients between CdIn2S4 and MgIn2S4 could accelerate the separation of electron-hole (e--h+) pairs in the CMIS heterojunction to enhance the photocurrent of CMIS, which was increased 5.5 and 80 times compared with that of single CdIn2S4 and MgIn2S4, respectively. Meanwhile, using CMIS as photoactive material, increasing the biocompatibility by dropping Pt NPs on the surface of CMIS to immobilize the antibody through Pt-N bond. Fe3O4-Ab2, acting as the quencher, competitively consumes electron donors and absorbs light, leading to photocurrent quenching. With the increasing of quencher, the photocurrent decreased. Hence, the developed "signal-off" PEC immunosensor realized the trace detection of NSE within the range from 1.0 fg/mL to 10 ng/mL with a low detection limit of 0.34 fg/mL. This strategy provided a new perspective for establishing ternary metal sulfide heterojunction to construct PEC immunosensor for sensitive detection of disease biomarkers.

An accelerated PETALUTE MRI sequence for in vivo quantification of sodium content in human articular cartilage at 3T.

OBJECTIVE: In this work, we evaluate the sodium magnetic resonance imaging (MRI) capabilities of a three-dimensional (3D) dual-echo ultrashort echo time (UTE) sequence with a novel rosette petal trajectory (PETALUTE), in comparison to the 3D density-adapted (DA) radial spokes UTE sequence in human articular cartilage in the knee. MATERIALS AND METHODS: We scanned five healthy subjects using a 3D dual-echo PETALUTE acquisition and two comparable implementations of 3D DA-radial spokes acquisitions, one matching the number of k-space projections (Radial - Matched Spokes) and the other matching the total number of samples (Radial - Matched Samples) acquired in k-space. RESULTS: The PETALUTE acquisition enabled equivalent sodium quantification in articular cartilage volumes of interest (168.8 ± 29.9 mM, mean ± standard deviation) to those derived from the 3D radial acquisitions (171.62 ± 28.7 mM and 149.8 ± 22.2 mM, respectively). We achieved a 41% shorter scan time of 2:06 for 3D PETALUTE, compared to 3:36 for 3D radial acquisitions. We also evaluated the feasibility of further acceleration of the PETALUTE sequence through retrospective compressed sensing with 2 × and 4 × acceleration of the first echo and showed structural similarity of 0.89 ± 0.03 and 0.87 ± 0.03 when compared to non-retrospectively accelerated reconstruction. CONCLUSION: We demonstrate improved scan time with equivalent performance using a 3D dual-echo PETALUTE sequence compared to the 3D DA-radial sequence for sodium MRI of articular cartilage.

Excited-State Dynamics of a Bright Fluorescent Dye with Precise Control of Emission Color Using Acid-Base Equilibrium, Intramolecular Charge Transfer, and Host-Guest Chemistry.

A fluorescent dye, a dithiophene-conjugated benzothiazole derivative (DTBz), was prepared to have high fluorescence emission quantum yields (ΦF) across various organic solvents. Its emission color modulation, from bright blue to deep red, was achieved through intramolecular charge transfer (ICT), acid-base equilibrium, and host-guest chemistry. Although it exhibits a weak solvatochromic effect, DTBz exhibited a bright fluorescence emission around 480 nm upon excitation at 390 nm in most solvents. In polar solvents, such as MeOH (methanol), EtOH (ethanol), DMF (N,N-dimethylforamide), and DMSO (dimethyl sulfoxide), an additional ICT emission band emerged around 640 nm, notably intense in DMSO, resulting in a bright greenish-white emission (ΦF = 0.67). The addition of 1,8-diazabicyclo[5,4.0]undec-7-ene (DBU) altered emission characteristics, reducing emission from the local excited (LE) state and enhancing ICT state emission. The degree of emission spectral change saturation with DBU addition varied with the solvent nature. Polar solvents with high dielectric constants, like DMSO and DMF, saw a complete disappearance of LE state emission with 5 equiv of DBU, resulting in a deep red emission (ΦFs of 0.53 and 0.48, respectively). Femtosecond transient absorption spectroscopy and time-resolved photoluminescence measurements elucidated the excited-state dynamics, revealing a long-lived excited state (τ-H = 10.3 ns) at a lower energy emission (640 nm), identified as DTBz-*, supported by transient absorption spectra analysis. Further analysis, including time-resolved fluorescence decay measurements and time-dependent density-functional theory (TD-DFT) calculations, underscored the role of deprotonation of DTBz's hydroxyl group in promoting the ICT process. The CIE coordination plot demonstrated wide linear emission color changes upon successive DBU additions in all solvents, while emission color precision was achieved through host-guest chemistry. Emission changes induced by DBU were reverted to the original state upon beta-cyclodextrin (ß-CD) addition, with the 1H NMR study revealing the competition between acid-base equilibrium and host-guest complex formation as the cause of emission color change.

Extremely Long-Lived Charge Donor States Formed by Visible Irradiation of Quantum Dots.

Using cyclic voltammetry under illumination, we recently demonstrated that CdS quantum dots (QDs) form charge donor states that live for at least several minutes after illumination ends, ∼12 orders of magnitude longer than expected for free carriers. This time scale suggests that the conventionally accepted mechanism of charge transfer, wherein charges directly transfer to an acceptor following exciton dissociation, cannot be complete. Because of these long time scales, this unconventional pathway is not readily observed using time-resolved spectroscopy to probe charge transfer dynamics. Here, we investigated the chemical nature of these charge donor states using cyclic voltammetry under illumination coupled with NMR spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and optical spectroscopy. Our data reveal that charges are stored locally rather than as free carriers, and the number of charges stored is dependent on the QD surface ligation and stoichiometry. Altogether, our results confirm that electrons are stored at ligated surface Cd, these sites are competent charge donors, and this storage is charge balanced by X-type ligand desorption. We found that charge storage occurs in every QD system studied, including CdS, CdSe, and InP capped with carboxylate and phosphonate ligands.

Asymmetric Charge Distribution in One-dimensional Metal-Organic Assemblies to Promote Photocatalytic Hydrogen Evolution.

The local charge distribution of photocatalyst is crucial to the catalytic activity due to its influence on the charge separation process. Herein, we report two one-dimensional Ni-based metal-organic assemblies for efficient photocatalytic hydrogen evolution without using noble-metal cocatalysts. By adjusting the aromatic ring in the center of the tricarboxylic ligand, the photocatalytic hydrogen evolution activity was increased from 1715 to 2652 µmol h-1 g-1. The detailed mechanism study shows that the introduced nitrogen atoms in the ligands of the metal-organic coordination assembly could modulate the local charge distribution, and yielding a significant enhancement of the molecular dipole moment which engenders a propulsive force for the effective separation and transport of photoinduced charge carriers. This work provides insights into the local charge distribution via ligand modulation for enhancing the activity of photocatalysts.

Coordination and Hydrogen Bond Chemistry in Tungsten Oxide@Polyaniline Composite toward High-Capacity Aqueous Ammonium Storage.

Aqueous ammonium ion batteries (AAIBs) have garnered significant attention due to their unique energy storage mechanism. However, their progress is hindered by the relatively low capacities of NH4 + host materials. Herein, the study proposes an electrodeposited tungsten oxide@polyaniline (WOx@PANI) composite electrode as a NH4 + host, which achieves an ultrahigh capacity of 280.3 mAh g-1 at 1 A g-1, surpassing the vast majority of previously reported NH4 + host materials. The synergistic interaction of coordination chemistry and hydrogen bond chemistry between the WOx and PANI enhances the charge storage capacity. Experimental results indicate that the strong interfacial coordination bonding (N: →W6+) effectively modulates the chemical environment of W atoms, enhances the protonation level of PANI, and thus consequently the conductivity and stability of the composites. Spectroscopy analysis further reveals a unique NH4 +/H+ co-insertion mechanism, in which the interfacial hydrogen bond network (N-H···O) accelerates proton involvement in the energy storage process and activates the Grotthuss hopping conduction of H+ between the hydrated tungsten oxide layers. This work opens a new avenue to achieving high-capacity NH4 + storage through interfacial chemistry interactions, overcoming the capacity limitations of NH4 + host materials for aqueous energy storage.

Dynamic Control of Asymmetric Charge Distribution for Electrocatalytic Urea Synthesis.

Constructing dual catalytic sites with charge density differences is an efficient way to promote urea electrosynthesis from parallel NO 3 - ${\mathrm{NO}}_3^ - $ and CO2 reduction yet still challenging in static system. Herein, a dynamic system is constructed by precisely controlling the asymmetric charge density distribution in an Au-doped coplanar Cu7 clusters-based 3D framework catalyst (Au@cpCu7CF). In Au@cpCu7CF, the redistributed charge between Au and Cu atoms changed periodically with the application of pulse potentials switching between -0.2 and -0.6 V and greatly facilitated the electrosynthesis of urea. Compared with the static condition of pristine cpCu7CF (FEurea = 5.10%), the FEurea of Au@cpCu7CF under pulsed potentials is up to 55.53%. Theoretical calculations demonstrated that the high potential of -0.6 V improved the adsorption of *HNO2 and *NH2 on Au atoms and inhibited the reaction pathways of by-products. While at the low potential of -0.2 V, the charge distribution between Au and Cu atomic sites facilitated the thermodynamic C-N coupling step. This work demonstrated the important role of asymmetric charge distribution under dynamic regulation for urea electrosynthesis, providing a new inspiration for precise control of electrocatalysis.

Selective Chromogenic Chemosensors for Arsenite Anion: A Facile Approach to Analyzing Arsenite in Honey, Milk, and Water samples.

In this study, two chemosensors, N5R1 and N5R2, based on 5-(4-nitrophenyl)-2-furaldehyde, with varying electron-withdrawing groups, were synthesized and effectively employed for the colorimetric selective detection of arsenite anions in a DMSO/H2O solvent mixture (8:2, v/v). Chemosensors N5R1 and N5R2 exhibited a distinct color change upon binding with arsenite, accompanied by a spectral shift toward the near-infrared region (Δλmax exceeding 200 nm). These chemosensors established stability between a pH range 6-12. Among them, N5R2 displayed the lowest detection limit of 17.63 ppb with a high binding constant of 2.6163×105 M⁻1 for arsenite. The binding mechanism involved initial hydrogen bonding between the NH binding site and the arsenite anion, followed by deprotonation and an intramolecular charge transfer (ICT) mechanism. The mechanism was confirmed through UV and 1H NMR titrations, cyclic voltammetric studies, and theoretical calculations. The interactions between the sensor and arsenite anions were further analyzed using global reactivity parameters (GRPs). Practical applications were demonstrated through the utilization of test strips and molecular logic gates. Real water samples, honey, and milk samples were successfully analyzed by both chemosensors for the sensing of arsenite.

Metal Cocatalyst Engineering in Metal-Semiconductor Hybrid Photocatalysts Achieves a Fivefold Enhancement of Hydrogen Evolution.

This study explores the optimal morphology of photochemical hydrogen evolution catalysts in a one-dimensional system. Systematic engineering of metal tips on precisely defined CdSe@CdS dot-in-rods is conducted to exert control over morphology, composition, and both factors. The outcome yields an optimized configuration, a Au-Pt core-shell structure with a rough Pt surface (Au@r-Pt), which exhibits a remarkable fivefold increase in quantum efficiency, reaching 86% at 455 nm and superior hydrogen evolution rates under visible and AM1.5G irradiation conditions with prolonged stability. Kinetic investigations using photoelectrochemical and time-resolved measurements demonstrate a greater extent and extended lifetime of the charge-separated state on the tips as well as rapid water reduction kinetics on high-energy surfaces. This approach sheds light on the critical role of cocatalysts in hybrid photocatalytic systems for achieving high performance.

Counterion Distribution in the Stern Layer on Charged Surfaces.

Counterion adsorption at the solid-liquid interface affects numerous applications. However, the counterion adsorption density in the Stern layer has remained poorly evaluated. Here we report the direct determination of surface charge density at the shear plane between the Stern layer and the diffuse layer. By the Grahame equation extension and streaming current measurements for different solid surfaces in different aqueous electrolytes, we are able to obtain the counterion adsorption density in the Stern layer, which is mainly related to the surface charge density but is less affected by the bulk ion concentration. The charge inversion concentration is further found to be sensitive to the ion type and ion valence rather than to the charged surface, which is attributed to the ionic competitive adsorption and ion-ion correlations. Our findings offer a framework for understanding ion distribution in many physical and chemical processes where the Stern layer is ubiquitous.