Interfacial Charge Transfer Resistance Research Articles

Advanced TiO2/Al2O3 Bilayer ALD Coatings for Improved Lithium-Rich Layered Oxide Electrodes.

Surface modification is a highly effective strategy for addressing issues in lithium-rich layered oxide (LLO) cathodes, including phase transformation, particle cracking, oxygen gas release, and transition-metal ion dissolution. Existing single-/double-layer coating strategies face drawbacks such as poor component contact and complexity. Herein, we present the results of a low-temperature atomic layer deposition (ALD) process for creating a TiO2/Al2O3 bilayer on composite cathodes made of AS200 (Li1.08Ni0.34Co0.08Mn0.5O2). Electrochemical analysis demonstrates that TiO2/Al2O3-coated LLO electrodes exhibit improved discharge capacities and enhanced capacity retention compared with uncoated samples. The TAA-5/AS200 bilayer-coated electrode, in particular, demonstrates exceptional capacity retention (∼90.4%) and a specific discharge capacity of 146 mAh g-1 after 100 cycles at 1C within the voltage range of 2.2 to 4.6 V. The coated electrodes also show reduced voltage decay, lower surface film resistance, and improved interfacial charge transfer resistances, contributing to enhanced stability. The ALD-deposited TiO2/Al2O3 bilayer coatings exhibit promising potential for advancing the electrochemical performance of lithium-rich layered oxide cathodes in lithium-ion batteries.

Achieving High Initial Coulombic Efficiency and Capacity in a Surface Chemical Grafting Layer of Plateau-type Sodium Titanate.

The plateau-type sodium titanate with suitable sodiation potential is a promising anode candidate for high safe and high energy density of sodium-ion batteries (SIBs). However, the poor initial Coulombic efficiency (ICE) and cyclic instability of sodium titanate are attributed to the unstable interfacial structure along with the decomposition of electrolytes, resulting in the continuous formation of solid electrolyte interface (SEI) film. To address this issue, a chemical grafting method is developed to fabricate a highly stable interface layer of inert Al2 O3 on the sodium titanate anode, rendering the high ICE and excellent cycling stability. Based on theoretical calculations, NaPF6 are more likely adsorption on the Al2 O3 surface and produce sodium fluoride. The formation of a thin and dense SEI film with rich sodium fluoride achieves the low interfacial resistances and charge-transfer resistances. Benefitting from our design, the obtained sodium titanate exhibits a high ICE from 67.7 % to 79.4 % and an enhanced reversible capacity from 151 mAh g-1 to 181 mAh g-1 at 20 mA g-1 , along with an increase in capacity retention from 56.5 % to 80.6 % after 500 cycles. This work heralds a promising paradigm for rational regulation of interfacial stability to achieve high-performance anodes for SIBs.

Development of Inverse-Opal-Structured Charge-Deficient Co9S8@nitrogen-Doped-Carbon to Catalytically Enable High Energy and High Power for the Two-Electron Transfer I+/I- Electrode.

The iodine (I) electrode involving two-electron transfer chemistry by converting between I+ and I-, has the potential to deliver theoretically doubled capacity and higher working voltage platforms, thus achieving higher energy density. However, owing to the slow kinetics of the cascade two-electron transfer reactions, the system suffers from large overpotentials and low power density, especially at high working currents and low temperatures. Here, an inverse-opal-structured cobalt sulfide@nitrogen-doped-carbon (Co9S8@NC) catalyst with unique charge-deficient states is developed to promote the reaction kinetics of the I-/I+ electrode. The charge-deficient Co9S8@NC catalyst not only enables strong physicochemical adsorption with the iodine species but also significantly reduces the activation energy and interfacial charge transfer resistance of the cascade I+/I0/I- conversion reaction. Consequently, the prototypical Zn‖I+/I0/I- battery equipped with the Co9S8@NC catalyst can deliver a high energy density of 554 Wh kg-1 and a stable cycle life of 5000 cycles at 30°C. Moreover, at a subzero temperature of -30 °C, the battery can exhibit enhanced kinetics and a high power density of 1514 W kg-1, high energy density of 485 Wh kg-1.

Ligand bridged MXene/metal organic frameworks heterojunction for efficient photocatalytic ammonia synthesis

Efficient interfacial charge transfer is imperative for enhancing N2 photofixation, yet controlling this process proves challenging. Herein, a unique ligand pre-coupling strategy was employed to design ligand-bridged MXene/MIL-125(Ti), creating a coordination bond between Ti3C2Ox and MIL-125(Ti) and forming a ligand-bridge, aiming to regulate interfacial electron transfer. Kelvin probe force microscopy and charge density difference analysis revealed the establishment of an electronic unidirectional transport channel from MIL-125(Ti) to Ti3C2Ox through this ligand-bridge. This effectively reduced the interface charge transfer resistance, enhanced the separation efficiency of charge carriers. Consequently, the Ti3C2Ox/MIL-125(Ti) manifested an excellent ammonia evolution rate of 103.02 μmol·gcat-1·h-1. Furthermore, the efficiency of this strategy for accelerating the separation of photogenerated carriers was demonstrated in five other MOFs, demonstrating its potential for constructing ligand-bridged MXene/MOFs heterojunctions.

Effect of two-fold single-atom substitutions (S, Se; C, N) in band gap engineered donor-acceptor conjugated microporous polymers on the efficient aerobic photooxidation of aryl sulfides.

Substitution of a single atom in a photoactive system is capable of vastly altering its optoelectronic properties leading to the generation of an efficient photocatalyst. In this study, we explore the impact of two-fold single-atom substitutions on the optoelectronic properties and photocatalytic performance of donor-acceptor type conjugated microporous polymers (D-A CMPs). For this, three isostructural triphenylamine (TPA)-based D-A CMPs were synthesized namely PTPA-BT, PTPA-BS, and PTPA-PS containing 2,1,3-benzothiadiazole, 2,1,3-benzoselenadiazole and [1,2,5]selenadiazolo[3,4-c]pyridine as the acceptor moieties, respectively. Firstly, PTPA-BT and PTPA-BS were synthesized using the S to Se single-atom substitution strategy, followed by the synthesis of PTPA-PS employing a second C to N single-atom substitution. The effect of single-atom substitution demonstrated drastic changes in their band gap, conductivity, and charge carrier dynamics, which in turn impacted their photocatalytic activity, although the change in their porosity was not much pronounced. In terms of photocatalytic detoxification of sulfur mustards, the activities of D-A CMPs follow the trend: PTPA-BS > PTPA-PS > PTPA-BT. In comparison with PTPA-BT (containing C, S) and PTPA-PS (containing N, Se), PTPA-BS (containing C, Se) exhibits a higher photocatalytic activity towards the photooxidation of thioanisole with >99% conversion and ∼93% isolated yield under visible-light illumination, which is attributed to its lower interfacial charge transfer resistance, stronger photocurrent response, optimal band gap and higher activity to generate superoxide anion radicals. Therefore, the two-fold single-atom substitution strategy is crucial for optimizing D-A CMPs for the photocatalytic oxidation of aryl sulfides. This approach allows fine-tuning of the optoelectronic properties to enhance photocatalytic efficiency and performance.

Ultra-fast green synthesis of a defective TiO2 photocatalyst towards hydrogen production.

An ultra-fast green synthesis of defective titanium dioxide (TiO2) photocatalysts was conducted by the microwave-assisted method using l-ascorbic acid (l-As) as a reducing agent. Effect of l-As concentrations on the chemical-, optical- and photoelectrochemical properties as well as the photocatalytic performance towards the hydrogen (H2) production was explored. The obtained TiO2 nanoparticles (NPs) illustrated the brown fine powders with different brownness levels depending on the concentrations of l-As. A high l-As concentration provided a high brownness of TiO2 NPs with a high generation of Ti3+ defects and oxygen vacancies (Ov), which can extend the light absorption towards the visible and near-infrared regions, suppress the recombination rate of electron-hole pairs, promote the photocurrent response and minimize the interface charge transfer resistance. An appropriate quantity of generated defects and good porous properties played a crucial role in photocatalytic H2 production. Under fluorescence illumination, the sample synthesized with a TiO2 and l-As weight ratio of 1 : 0.25 (PAs0.25) exhibited the highest H2 production rate (∼162 μmol g-1 h-1 in the presence of 1 wt% Au co-catalyst) with a slight drop (∼8.2%) after the 5th use (15 h). The synthesis method proposed in this work provides a new insight to an ultra-fast synthesis of defective TiO2 NPs using an eco-friendly chemical precursor under non-severe conditions.

Asymmetric Fe-O2-Ti structures accelerate reduced-layer-FeII “electron” conversion: Facilitating photocatalytic nitrogen fixation

As a green and sustainable method for ammonia production, solar photocatalytic nitrogen fixation (PNRR) provides a new approach to slowing down the consumption of non-renewable energy resources. Given the extremely huge energy required to activate inert nitrogen, a rational design of efficient nitrogen fixation catalytic materials is essential. This study constructs defective Ti3+-Ti3C2Ox to regulate the NH2-MIL-101(Fe) reduced layer-FeII 'electron' transition; meanwhile, the heterojunction interface electronic structure formed by coupling promotes catalytic charges' transfer/separation, while the interface-asymmetric Fe-O2-Ti structure accelerates the response with nitrogen. It is shown that the heterojunction NM-101(FeII/FeIII)-1.5 exhibits a 75.1 % FeII enrichment (FeII:FeIII), which successfully impedes the fouling relationship between the two (FeII/FeIII). Mössbauer spectroscopy analysis demonstrates that the presence of D1-high spin state FeIII and D2-low/medium spin state FeII structures in the heterojunction boosts the PNRR activity. Furthermore, it is found that the defective state Ti3+-Ti3C2Ox modulation enhances the reduced nitrogen fixation capacity of the heterojunction (CB = -0.84 eV) and decreases the interfacial charge transfer resistance, yielding 450 umol·g−1·h−1 ammonia. Furthermore, this study modulates the charge ration of the catalyst reduction layer by constructing a charge-asymmetric structure with Ti3+-deficient carriers; this method provides a potential opportunity for enhancing photocatalytic nitrogen fixation in the future.

One-pot synthesis of an Au modified BiOCOOH plasmonic photocatalyst with enhanced photocatalytic activity

In this work, we designed the plasmonic photocatalyst of Au–BiOCOOH through a one-pot method, which can be used to effectively treat wastewater contaminated with rhodamine (RhB) and tetracycline (TC). Compared with neat BiOCOOH, as expected, the resulting Au–BiOCOOH illustrated significantly boosted photocatalytic efficiency for degrading RhB and TC under visible light illumination. Remarkably, 3.0%Au–Bi showed the most optimal performance against RhB and TC, achieving degradation rates of 99.5 % and 99.7 % within 120 min. Through multiple characterization techniques, the physical and chemical photoelectric properties of the photocatalyst as well as the photocatalysis mechanism were discussed in detail. UV–visible diffuse reflectance spectroscopy (DRS) analysis demonstrates that the loading of Au nanoparticles (Au NPs) onto 2D nanosheets of BiOCOOH significantly expanded the wavelength range of response of BiOCOOH to visible light. Separately, the outcomes of electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) manifestly reveal that the presence of Au NPs on BiOCOOH can efficiently reduce the interfacial charge transfer resistance and accelerate the photogenerated charge transfer. The free radical trapping test provided evidence for the essential role played by holes (h+) and superoxide radicals (·O2−) were involved in the degradation of RhB. The study provided a possibility to improve the photocatalytic efficiency of BiOCOOH.

Electrochemical treatment of antibiotic wastewater containing ceftriaxone sodium by porous Ti/Magnéli Ti4O7 nanotube arrays

In this study, porous Ti/Magnéli Ti4O7 nanotube arrays (NTA) was fabricated to pretreat antibiotic wastewater. Characterization of the Ti4O7-NTA illustrated that highly ordered NTA was successfully generated on the porous Ti substrate, which enlarged the specific surface area by 1.67 times. The Ti4O7-NTA has a high oxygen evolution potential (2.60 V) as well as low interfacial charge transfer resistance (4.479 Ω cm−2). Ceftriaxone sodium (CRO) was completely removed from raw antibiotic wastewater after 3 h of treatment by the Ti4O7-NTA, under optimal operation conditions. The biodegradability and toxicity of the wastewater were also significantly enhanced and reduced, as the BOD/COD and EC50,48h values were increased to 0.48 and 57.62 % ± 2.16 %, respectively. The possible degradation pathway of CRO was proposed by LC‒MS. Cathodic polarization was proven to be an effective way to ensure the long-term durability of the Ti4O7-NTA.

Stoichiometric ratio-modulated nickel sulfides nanosheet arrays for electrocatalytic oxygen reduction reaction toward hydrogen peroxide production

Nickel sulfides (Ni2S3, NiS, and NiS2) nanosheets (NSs) with different stoichiometric ratios were synthesized through low-temperature chemical conversion routes. Among them, the as-synthesized NiS2 NSs showed the best electrocatalytic ORR activity toward H2O2 production because of large electrochemically active surface area, small interfacial charge transfer resistance, and high 2e− reaction process selectivity. In addition, the as-synthesized NiS2 NSs showed good durability and electrocatalytic inertness to the decomposition of H2O2. The stoichiometric ratios engineering provided a new strategy for designing highly efficient electrocatalysts toward H2O2 generation.

Exploring the impact of electron transport layer thickness and morphology on perovskite infiltration and photoresponse in HTM-free self-powered photodetector

Methylammonium lead Iodide (MAPbI3) is emerging as the frontrunner for high-performance photo-detection due to its superior optoelectronic characteristics and ease of processing. Titanium dioxide (TiO2) is the commonly employed electron transport layer in conventional perovskite-based photodetectors. However, the fundamental understanding of the role of TiO2 morphology and its thickness on the photodetector performance is yet to be explored explicitly. This work systematically investigates the impact of morphology (mesoporous versus compact TiO2 layer) and thickness of the TiO2 layer (50 nm – 3000 nm) on the MAPbI3 photodetector performance. The devices have been fabricated in a hole transport material (HTM)-free architecture with carbon as the top contact. The heterojunction between MAPbI3 and TiO2 renders the device with self-powered capability. The influence of the perovskite sensitisation in the TiO2 electrodes, carrier recombination characteristics and charge-carrier transfer resistances have been studied using photoluminescence and impedance spectroscopy. The TiO2 layer morphology and thickness affected the MAPbI3 infiltration and film formation kinetics. Impedance and photoluminescence spectroscopies reveal that TiO2 layers, with thickness above 460 nm, negatively affected the device performance. An optimum thickness of 460 nm-mesoporous TiO2 layer exhibited a superior responsivity and rise time of 2.9 A/W and 21 ms, respectively. The poor performance at higher thicknesses is due to the increased interfacial charge transfer resistance and charge carrier recombination. This work is the first report of extensive optimisation and study on the impact of TiO2 film morphology and thickness on the MAPbI3 photodetectors. The present work will be a key for modelling and designing high-performance perovskite photodetectors.

Self-Transformation of Atomically Precise Alloy Nanoclusters to Plasmonic Alloy Nanocrystals: Evaluating Photosensitization in Solar Water Oxidation.

Atomically precise alloy nanoclusters (NCs) inherit the advantages of homometal NC counterparts such as atomic stacking fashion, quantum confinement effect, and enriched catalytic active sites and simultaneously possess the advantageous physicochemical properties such as significantly enhanced photostability, ideal photosensitization efficiency, and favorable energy band structure. Nevertheless, elucidation of the roles of alloy NCs and alloy nanocrystals (NYs) in boosting solar water oxidation has so far not yet been reported owing to the deficiency of applicable alloy NC photosystems. Herein, utilizing the generic thermal-induced self-transformation of alloy NCs to alloy NYs, we comprehensively explore the photosensitization properties of glutathione (GSH)-capped alloy NCs (AgxAu1-x@GSH and CuxAu1-x@GSH) and the corresponding alloy NY (AgAu and CuAu) counterparts in solar water oxidation reaction. The results imply that photoelectrons of alloy NCs surpass the hot electrons over plasmonic alloy NYs in stimulating the PEC water oxidation reaction. The photoelectrons of alloy NCs demonstrate lower interfacial charge-transfer resistance, longer carrier lifetime, and a more enhanced photosensitization effect with respect to the plasmonic alloy NYs, contributing to the significantly boosted photoelectrochemical water oxidation activities. Moreover, we found that our result is universal.

In-situ grown carbon as charge transfer medium for enhanced photoinduced electrons extraction from polymer carbon nitride toward TiO2

Interfacial charge transfer resistance is one of the main limiting factors for realizing high photocatalytic efficiency of heterostructures system. Herein, an activated carbon layer is successfully introduced between the interface of polymer carbon nitride (CN) and TiO2 heterostructure (CNP-x) as charge transfer medium by in situ pyrolysis carbonization method. Because of the lower spatial resistance of the crystalline/amorphous interface and the fast carrier transportation character of activated carbon, the efficiency of TiO2 in extracting photoinduced electrons from CN was significantly improved. That is, the separation/transport of photocarriers in CNP-x heterostructure is accelerated, and the recombination time of photogenerated electrons and holes is prolonged. The CNP-1 exhibits a H2 evolution rate of 1298.5 μmol h−1 with apparent quantum yield (AQY) of 34.5 %, 20.3 % and 12.6 % at 365 nm, 380 nm and 400 nm, respectively. This work offers a novel and unique strategy to promote interface charge separation and transport of CN-based heterostructures by accurately introduction charge transfer medium.

Aminosilanized Interface Promotes Electrochemically Stable Carbon Nitride Films with Fewer Trap States on FTO for (Photo)electrochemical Systems.

We have demonstrated the direct growth of a CNx layer on a plasma-cleaned and aminosilanized F-doped SnO2 (FTO) electrode to study the CNx|FTO interface that is critical for (photo)electrocatalytic systems. The (3-aminopropyl)triethoxysilane (APTES) was chosen as a bifunctional organosilane, with the amino end incorporating into CNx and the silane end connecting to the hydroxylated FTO surface. Plasma cleaning and aminosilanization resulted in a highly hydrophilic surface, which leads to better contact of melted thiourea to the aminosilanized FTO (p-FTONH2) during CNx polymer condensation, thus generating a thinner and more compact CNx layer. The modification at the interface was shown to influence the CNx growth on length scales of tens of micrometers. We grew CNx thin films on p-FTONH2 (CNx/p-FTONH2) and nonaminosilanized p-FTO (CNx/p-FTO). CNx/p-FTONH2 had a smaller density of trap states and passed 2.4 times the charges before failure compared to CNx/p-FTO. Additionally, a 40% decrease in interfacial charge transfer resistance at the CNx|electrolyte interface was measured for CNx/p-FTONH2 compared to CNx/p-FTO under -0.5 V vs RHE in 0.1 M Na2SO4. Furthermore, with the CNx surface coated with a Pt cocatalyst, Pt/CNx/p-FTONH2 exhibited faster hydrogen evolution rates and larger current densities than Pt/CNx/p-FTO. The highest Faraday efficiency toward electrochemical hydrogen evolution (FEH2) in 0.1 M Na2SO4 (pH = 7) was 46.1%, 37.3%, 57.7%, and 70.5% for Pt/CNx/p-FTONH2, Pt/CNx/p-FTO, CNx/p-FTONH2, and CNx/p-FTO, respectively. The increase in hydrogen evolution rate did not follow the magnitude of the current density change, indicating electrochemical processes other than proton reduction. Overall, we have carefully investigated the CNx|FTO interface and suggested potential solutions to make CNx films better (photo)electrodes for (photo)electrochemical systems.

All‐Solid‐State Battery Fabricated by 3D Aerosol Jet Printing

All‐solid‐state battery (ASSB) technology has emerged as a promising solution for developing safe and high‐energy‐density power sources. However, the pronounced interfacial charge transfer resistance between the electrode and the solid electrolyte continues to be a central obstacle in contemporary ASSBs. This work demonstrates the first approach to printing ASSBs using aerosol jet printing technology. A composite cathode, composed of active materials, binder polymer, and conductive filler, is printed onto the current collector. Subsequently, a solventless superionic conducting solid polymer electrolyte is printed on the cathode to form a seamless interface between the electrode and the electrolyte, resulting in a 3D‐printed all‐solid‐state lithium‐ion battery. The active material in the cathode (lithium iron phosphate, LFP) achieves a loading of ≈10 mg cm−2, while the solid polymer electrolyte layer maintains a thickness of a mere 24 μm. Under ambient conditions (30 °C), the half‐cell ASSB exhibits a specific capacity of over 130 mAh g−1 at 0.05 C. Advanced aerosol printed cells with a porous membrane, which allows the batteries to be safely cycled at higher temperature (60 °C), exhibit fast charging/discharging rates. These batteries are capable of cycling at a 0.3 C rate, delivering a specific capacity surpassing 160 mAh g−1.

Quantitative measurement of CA 15-3 cancer biomarker using an electrochemical aptasensor based on the electrodeposition of Au thin film on cauliflower-like rGO-MoS2 nanocomposite.

The present research was conducted to design and construct an electrochemical aptasensor for evaluating carbohydrate antigen 15-3 (CA15-3) as a biomarker for breast cancer. The aptasensor has been fabricated by a gold thin film (AuTF) electrodeposited on a cauliflower-like reduced graphene oxide-molybdenum sulfide nanocomposite (rGO-MoS2). The modified electrode's surface was used to immobilize the thiolated aptamer, which was subsequently treated with CA 15-3 antigen. The aptasensor fabrication process was assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This research also applied EIS to the quantitative measurement of CA 15-3 antigen by the proposed aptasensor. The interfacial charge transfer resistance (Rct) alteration before and after incubation of CA 15-3 by theimmobilized aptamer was considered a signal for the quantitative measurement of CA 15-3. A linear concentration ranging from 5.0 to 200.0 U mL-1 with a detection limit of 3.0 × 10-1 U mL-1 was obtained for CA 15-3 using the EIS method. This designed aptasensor indicates satisfactory repeatability and stability, good selectivity, and high sensitivity. Moreover, clinical samples were assayed by the prepared aptasensor and compared with the ELISA method, yielding acceptable results. Therecovery and relative standard deviation (RSD) of CA 15-3 in human serum samples were in the range 95.0 to 107.0% and 3.5 to 7.5%, respectively.

Amphiphilic Cobalt Phthalocyanine Boosts Carbon Dioxide Reduction.

Due to the easy accessibility, chemical stability and structural tunability of macrocyclic skeleton, cobalt phthalocyanines immobilized on carbon supports offer an ideal research model for advanced electrochemical carbon dioxide reduction reaction (eCO2 RR). Herein, for the first time, an amphiphilic cobalt phthalocyanine (TC-CoPc) is loaded on multiwalled carbon nanotubes to unveral the roles of hydrophilic/hydrophobic properties on catalytic efficiency. To our surprise, the resultant electrode exhibits FECO of 95% for CO2 RR with TOF of 29.4 s-1 at the overpotential of 0.585V over long-term electrolysis in H-type cell. In membrane electrode assembly device (MEA), the boosted transport of water vapor to catalyst layer slows down carbonate crystallization and enhances the stability of the electrode with FECO value of > 99% over 27 hours at -0.25 A, which represents the best selectivity and stability among reported molecular catalysts in MEA devices. The amphiphilic cobalt phthalocyanine, which decreases interfacial charge and mass transfer resistance and maintains effective contact between active sites and the electrolyte, highlights the exceptional CO2 conversion from molecular perspective. This article is protected by copyright. All rights reserved.

Defect controlled diffusion of lithium ions in Mn doped V2O5 for potential applications as cathode material

With a motivation to unravel the effect of cation (Mn) doping-induced modifications in structure, charge transfer resistance, and Li-ion diffusion in V2O5 a systematic study using X-ray diffraction (XRD), Raman Spectroscopy and electrochemical impedance spectroscopy (EIS) has been employed using three electrodes configuration. Structural investigations using XRD suggest the selective diffusion of Mn ion towards the c-axis at a low doping percentage. Raman spectroscopy suggests the shift in 994 cm-1 modes which substantiates the uniaxial diffusion of Mn ions. Nyquist plots show that interfacial charge transfer resistance is highest for the lowest doping i.e., 1% Mn-doped V2O5 and exhibits the lowest diffusion coefficient as compared to other doped V2O5 samples. Specific capacitance calculated from cyclic voltammetry is found to be highest for the 4% Mn-doped V2O5 sample. Moreover, diffusion of Lithium ions improves with an increase in doping concentration due to higher concentration of defects as evident from Δd/d and Nelson–Riley factor (NRF) for pure V2O5 and Mn-doped V2O5.

Hybridization Chain Reaction-Enhanced Biocatalytic Precipitation on Flower-like Bi2S3: Toward Organic Photoelectrochemical Transistor Aptasensing with High Transconductance.

Organic photoelectrochemical transistor (OPECT) bioanalysis has recently emerged as a promising avenue for biomolecular sensing, providing insight into the next-generation of photoelectrochemical biosensing and organic bioelectronics. Herein, this work validates the direct enzymatic biocatalytic precipitation (BCP) modulation on a flower-like Bi2S3 photosensitive gate for high-efficacy OPECT operation with high transconductance (gm), which is exemplified by a prostate-specific antigen (PSA)-dependent hybridization chain reaction (HCR) and subsequent alkaline phosphatase (ALP)-enabled BCP reaction toward PSA aptasensing. It has been shown that light illumination could ideally achieve the maximized gm at zero gate bias, and BCP could efficiently modulate the device's interfacial capacitance and charge-transfer resistance, resulting in a significantly changed channel current (IDS). The as-developed OPECT aptasensor realizes good analysis performance for PSA with a detection limit of 10 fg mL-1. This work features direct BCP modulation of organic transistors and is expected to stimulate further interest in exploring advanced BCP-interfaced bioelectronics with unknown possibilities.

Synthesis of AuX (X = Ni, Ga, Mo, Zn, and Cr) Alloy Aerogels as High-Performance Electrocatalytic CO2 Reduction Reaction Catalysts.

Electrocatalytic CO2 reduction reaction (eCO2RR) into value-added chemicals is highly desirable to mitigate the global warming effect and energy crisis. Metal aerogels, as featured by a self-supporting structure, large specific surface area, outstanding conductivity, and a hierarchical porous structure, are ideal electrocatalysts in eCO2RR. Herein, we report a simple and general strategy for constructing a series of Au-based alloy aerogels which contain Au with another metal including Ga, Ni, Mo, Zn, and Cr, respectively. For the first time, the electrocatalytic activities of AuGa aerogels, AuNi aerogels, and AuMo aerogels for CO2RR were studied in detail. The resultant Au81Ga19 aerogel achieves a 95.2% Faradaic efficiency (FE) at -1.16 V versus reversible hydrogen (vs RHE) in H-cells. Impressively, a total 99.4% FE for C1 products (CO + HCOOH) with a current density of 100 mA cm-2 at -0.6 V vs RHE and a large current density of 228 mA cm-2 can be achieved at -0.9 V with a 72.3% FE for the C1 product in a flow cell. Electrochemical characterization and theoretical calculations further revealed that the outstanding performance of the Au-based aerogels was derived from the large specific surface area, abundant grain boundaries, low interfacial charge transfer resistance, and synergetic effect. Overall, this study provides a promising alternative to engineer alloy aerogel electrocatalysts for highly efficient CO2 electroreduction.