Accelerate Electron Transfer Research Articles

Targeted Electrocatalysis for High‐Performance Lithium–Sulfur Batteries

The intricate sulfur redox chemistry involves multiple electron transfers and complicated phase changes. Catalysts have been previously explored to overcome the kinetic barrier in lithium–sulfur batteries (LSBs). This work contributes to closing the knowledge gap and examines electrocatalysis for enhancing LSB kinetics. With a strong chemical affinity for polysulfides, the electrocatalyst enables efficient adsorption and accelerated electron transfer reactions. Resulting cells with catalyzed cathodes exhibit improved rate capability and excellent stability over 500 cycles with 91.9% capacity retention at C/3. In addition, cells were shown to perform at high rates up to 2C and at high sulfur loadings up to 6 mg cm−2. Various electrochemical, spectroscopic, and microscopic analyses provide insights into the mechanism for retaining high activity, coulombic efficiency, and capacity. This work delves into crucial processes identifying pivotal reaction steps during the cycling process at commercially relevant areal capacities and rates.

Modulating structure of Ce-UiO-66 by introducing fluorinated terephthalic acid for enhanced removal efficiency of antibiotics: Insights into degradation kinetics and pathways

In this work, the 2-fluoroterephthalic acid with asymmetric structure and high electronegative F species was introduced in the assembly of Ce-UiO-66 catalysts to increase the defect density and enlarge pore structure for enhancement in removal efficiency of sulfamethoxazole. Owing to the strong coordination ability from high electronegative F species of 2-fluoroterephthalic acid with Ce-oxo nodes, the designed CUF exhibited improved interfacial properties (accelerated electron transfer rate, available active sites and enhanced interaction with PMS), which was favorable for the exploration and accessibility of active sites with sulfamethoxazole and PMS to decrease the adsorption barrier and accelerate PMS activation. As a result, the CUF catalysts exhibited higher adsorption capacity (173.4 mg/g) than that of CUH (117.8 mg/g), the enhanced degradation efficiency of sulfamethoxazole with a rate constant higher than 2.3 times CUH, good elimination (>95 %) of methylene blue, tetracycline and ibuprofen. In addition, the CUF/PMS system possessed satisfactory stability in wide solution pH, recycling and real water and good potential application in continuous wastewater treatment based on the designed dynamic catalytic reactor. This work provided deep insight into the design of catalysts with high adsorption performance and degradation efficiency based on the structure–activity relationship.

Atomically Asymmetrical Ir-O-Co Sites Enable Efficient Chloride-mediated Ethylene Electrooxidation in Neutral Seawater.

The chloride-mediated ethylene oxidation reaction (EOR) of ethylene chlorohydrin (ECH) via electrocatalysis is practically attractive because of its sustainability and mild reaction conditions. However, the chlorine oxidation reaction (COR), which is essential for the above process, is commonly catalyzed by dimensionally stable anodes (DSAs) with high contents of precious Ru and/or Ir. The development of highly efficient COR electrocatalysts composed of nonprecious metals or decreased amounts of precious metals is highly desirable. Herein, we report a modified Co3O4 with a single-atom Ir substitution (Ir1/Co3O4) as a highly efficient COR electrocatalyst for chloride-mediated EOR to ECH in neutral seawater. Ir1/Co3O4 achieves a Faradaic efficiency (FE) of up to 94.8% for ECH generation and remarkable stability. Combining experimental results and density functional theory (DFT) calculations, the unique atomically asymmetrical Ir-O-Co configuration with a strong electron coupling effect in Ir1/Co3O4 can accelerate electron transfer to increase the reaction kinetics and maintain the structural stability of Co3O4 during COR. Moreover, a coupling reaction system integrating the anodic chloride-mediated and cathodic H2O2-mediated EOR show a total FE of ~170% for paired electrosynthesis of ECH and ethylene glycol (EG) using ethylene as the raw material. The technoeconomic analysis highlights the promising application prospects of this system.

Atomically Asymmetrical Ir–O–Co Sites Enable Efficient Chloride‐mediated Ethylene Electrooxidation in Neutral Seawater

The chloride‐mediated ethylene oxidation reaction (EOR) of ethylene chlorohydrin (ECH) via electrocatalysis is practically attractive because of its sustainability and mild reaction conditions. However, the chlorine oxidation reaction (COR), which is essential for the above process, is commonly catalyzed by dimensionally stable anodes (DSAs) with high contents of precious Ru and/or Ir. The development of highly efficient COR electrocatalysts composed of nonprecious metals or decreased amounts of precious metals is highly desirable. Herein, we report a modified Co3O4 with a single‐atom Ir substitution (Ir1/Co3O4) as a highly efficient COR electrocatalyst for chloride‐mediated EOR to ECH in neutral seawater. Ir1/Co3O4 achieves a Faradaic efficiency (FE) of up to 94.8% for ECH generation and remarkable stability. Combining experimental results and density functional theory (DFT) calculations, the unique atomically asymmetrical Ir‐O‐Co configuration with a strong electron coupling effect in Ir1/Co3O4 can accelerate electron transfer to increase the reaction kinetics and maintain the structural stability of Co3O4 during COR. Moreover, a coupling reaction system integrating the anodic chloride‐mediated and cathodic H2O2‐mediated EOR show a total FE of ~170% for paired electrosynthesis of ECH and ethylene glycol (EG) using ethylene as the raw material. The technoeconomic analysis highlights the promising application prospects of this system.

Spring Expanding-like Polarity Reversal in Photoelectrochemical Biosensing.

Although polarity-reversal photoelectrochemical (PEC) analysis can effectively eliminate false-positive and negative signals caused by interferents, achieving high sensitivity and accuracy is still a challenge. Hence, a spring expanding-like polarity reversal strategy with bipolar signal synergistic amplification is first proposed to help build a high-performance PEC analysis system. In this study, l-cysteine (l-cys) is discovered to not only act as a polarity regulator to elaborately reverse photocurrent via its covalent bond to Cu and Bi but also provide a relatively stable electron donor to effectively consume the photogenerated holes compared with commonly used H2O2 and ascorbic acid. More importantly, the amino and electron-rich functional acridine groups in the dye acriflavine endow an electrochemical activity to accelerate electron transfer between the electrode and solution, thus enabling bipolar synergistic signal amplification for acquiring an extremely enlarged photocurrent variation that is of great significance to overcome the rigorous signal prereversal depression and reversal amplification in traditional polarity-reversal systems. Accordingly, the PEC biosensor with the proposed spring expanding-like polarity reversal strategy exhibits excellent sensitivity and accuracy, reflecting ultralow detection limits of 0.04 fM toward lead ions (Pb2+) and good anti-interference ability in the detection of natural water samples. This work provides an avenue for exploring a new polarity reversal strategy for accomplishing high-performance PEC bioanalysis, expected to be widely applied in environmental monitoring, clinical diagnosis, and food supervision.

Novel strategies for enhancing energy metabolism and wastewater treatment in algae-bacteria symbiotic system through carbon dots-induced photogenerated electrons: The definitive role of accelerated electron transport

The nitrogen removal efficiency of the algae-bacteria symbiotic system (ABSS) remains challenging due to competition for light capture and insufficient electron donors in aquaculture wastewater. To overcome this bottleneck issue, we first identified and reported the introduction of photogenerated electrons into ABSS by coupling them with carbon dots (CDs). The energy metabolism (21.52 %-56.25 %) and pollutant degradation efficiency (89.36 %-96.42 %) of ABSS/CDs surpassed the biochemical limit observed in traditional ABSS. Notably, the addtion of CDs facilitated an opening of the plastoquinone-pool (PQ-pool) valve and accelerated electron transfer rates, enabling photogenerated electrons to selectively target light-harvesting complexs as activation sites, thereby mobilizing photosynthesis and respiratory system activity to enhance nicotinamide adenine dinucleotide reduced (NADH) and adenosine triphosphate (ATP) production while promoting tricarboxylic acid (TCA) and Calvin cycle processes. In simulated swine wastewater treatment, ABSS/CDs achieved higher removal rates for the chemical oxygen demand (COD), total nitrogen (TN) and ammonium-nitrogen (NH4+-N) (100 %, 99.23 % and 98.62 % respectively) compared to pure culture systems alone. Network-based analysis revealed that ABSS/CDs improved microbial community structure stability within the photobioreactor while demonstrating efficient coupling between fungi, nitrifying bacteria, and denitrifying bacteria for enhanced performance in nitrogen removal processes. The upregulation of nitrogen metabolism and PQ-pool genes maintains efficient electron transport rates and contributes to nitrogen removal. This study expands our understanding of the physiological aptitudes of ABSS and provides valuable insights into applying CDs photoelectrons for enhanced wastewater treatment.

Simple solution immersion for realizing bifunctional catalyzation of water splitting in various electrolytes

Developing cost-effective, highly efficient and scalable bifunctional electrocatalysts for hydrogen production is crucial for advancing hydrogen energy systems. However, current methods are hindered by high energy consumption and material limitations. This work introduces a bifunctional electrocatalyst (NiFe-OH@Co2P@NF), by simply immersing a hierarchical cobalt phosphide electrode in mixed Ni/Fe solution, followed by forming layered nickel-iron hydroxides on the surface. Electrochemical tests reveal that this catalyst enhances active site exposure, accelerates electron transfer, and significantly lowers the overpotential for water electrolysis. It requires minimal overpotentials (79 mV at 10 mA cm−2, 175 mV at 150 mA cm−2) in 1 M KOH solution. In a dual-electrode electrolytic cell system, the catalyst enables efficient hydrogen production at a current density of 10 mA cm−2 with just 1.52 V, demonstrating robust stability during prolonged alkaline water splitting tests. Moreover, the bifunctional electrodes display good performance and durability in simulated alkaline seawater and 1 M KOH + seawater.

Rationally designed photothermal-pyroelectric Fe0.9Ni0.1S2/ZnSnO3 Z-scheme heterojunction for promoting electrical charge polarization towards optimized photocatalytic H2 evolution and intermolecular N-N coupling reaction

Developing a photocatalytic composite system that can couple hydrogen (H2) evolution and benzylamine (BA) oxidation is a challenging task, especially while avoiding sacrificial agents and value-added chemicals. Here, a practical approach is reported to develop a photothermal-pyroelectric-Fe0.9Ni0.1S2/ZnSnO3 photocatalytic system with core–shell and Z-scheme heterostructure via hydrothermal and annealing methods. Although Fe0.9Ni0.1S2 nanoparticles (NPs) could convert most of near-infrared (NIR) light energy into heat energy to drive the pyroelectric effect of ZnSnO3, it also results in temperature fluctuations (ΔT) in the system, causing natural polarization and thermoelectric effects under the condensed water circulation. As a result, the as-designed Fe0.9Ni0.1S2/ZnSnO3-2 composites could yield up to 7.194 mmol g-1h−1 with exceptional photocatalytic H2 evolution under simulated sunlight. This result is 5.41 and 4.92-fold those of Fe0.9Ni0.1S2 and ZnSnO3, respectively, with 16.66 % apparent quantum yield (AQY) under 365 nm monochromatic light. At the same time, the composites could also oxidize BA and yield up to 6.640 mmol g-1h-1n-benzylidene benzylamine (NBBA) with a 90.2 % selectivity. Due to the synergistic effect of Z-scheme’s built-in electric field and photothermal-pyroelectric of Fe0.9Ni0.1S2/ZnSnO3, the surface charges released on them could direct the charge transfer pathways and restrain their recombination with accelerated electron transfer kinetics, thus extending the carrier lifetime. This work offers a new perspective for designing electrical charge polarized by the photothermal-pyroelectric effect, which can enhance H2 evolution and BA oxidation concurrently.

Coupled Lattice‐Expanded Ni and MoO2 Array for Efficient Alkaline Hydrogen Evolution

AbstractTransition metal oxides have attracted much attention due to their good electrical conductivity, high chemical stability, and easy electronic structure modulation. However, it is still a great challenge to solve the problems of sluggish reaction kinetics and high overpotential in the alkaline hydrogen evolution reaction (HER) due to their poor intrinsic activity. Herein, a lattice‐expanded Ni‐decorated MoO2 array (Ni‐MoO2‐700) catalyst is prepared for the alkaline HER. Unlike most of the reported literature, the decoration of metal heteroatoms may lead to lattice expansion of the carrier catalyst. In contrast, lattice expansion of Ni is also achieved by adjusting the annealing temperature in this work. The Ni‐induced lattice‐expanding effect can not only modulate the electronic structure of the catalyst but also accelerate electron transfer during the reaction, thus increasing its intrinsic activity for the HER. As a result, Ni‐MoO2‐700 exhibits significantly enhanced catalytic activity with an overpotential of 74.9 mV at 10 mA cm−2 in 1.0 m KOH, which is far superior to that of most of the reported advanced Ni‐ and Mo‐based materials. This work provides deep intrinsic insight and a great opportunity to design efficient transition metal oxide catalysts for the alkaline HER.

Enhancing photosynthesis of microalgae via photoluminescent g-C3N4 accelerated photoelectrons transfer in photosystem

Using photoluminescent (PL) graphitic carbon nitride (g-C3N4) to convert ultraviolet (UV) light into chloroplast absorbed blue or near infrared (NR) is an attractive methodology to facilitate sunlight energy storage and carbon sequestration by microalgae. However, most researches focus on inhibiting water bloom by g-C3N4, applying PL g-C3N4 to promote growth of microalgae is rarely reported. Accordingly, PL g-C3N4 is synthesized by a microwave heating method and co–cultured with Chlorella vulgaris (C. vulgaris) with concentration of 0, 50, and 250 mg/L, named as C. vulgaris-0, C. vulgaris-50, and C. vulgaris-250, respectively, to study effect of PL g-C3N4 on growth of C. vulgaris. Results indicate that there is no significant effect of microwave synthesized g-C3N4 on morphology of microalgae cells, while cell viability and growth rate of C. vulgaris-50 is obviously enhanced. Further analysis indicates that, on the one hand, PL fluorescence at 615 nm enlarges light absorption of microalgae; on the other hand, photogenerated electrons by g-C3N4 accelerate electron transfer in photosystem, subsequently enhancing formation of NADPH and ATP, which is favorable to growth of microalgae. Metabolism analysis illustrates that glucose, fructose, and galactose, involved in glycolysis and photosynthesis, are all up-regulated in C. vulgaris-50 group. This work reveals low concentration of PL g-C3N4 facilitates protein synthesis and energy metabolism through enhancing light absorption and electron transfers, providing a biochemical strategy to enhance carbon sequestration.

CoFe2O4/carbon nitride Z-scheme heterojunction photocatalytic PMS activation for efficient tetracycline degradation: Accelerated electron transfer

The escalating consumption of antibiotics and their subsequent discharge into the water supply is a matter of significant concern. This study presents an innovative visible light (VL) activated peroxymonosulfate (PMS) system for efficient degradation of the targeted antibiotic tetracycline (TC). CoFe2O4/carbon nitride (CFO/CN) Z-scheme heterojunctions were designed and synthesized through a simple co-precipitation and calcination strategy. Surface and analytical techniques were employed to comprehensively characterize the prepared CFO/CN, demonstrating its enhanced efficiency in separating photoinduced charge carriers. CFO/CN exhibited a 27-fold enhancement in TC degradation rate constants with PMS under VL. The effects of various factors including catalyst dosage, PMS concentration, initial pH, and content of CFO on TC degradation efficiency were investigated. Reactive species quenching and EPR measurements revealed the main contribution of superoxide radicals (•O2−) made to TC degradation. TC degradation pathways were proposed based on oxidized product analysis. The assessment of acute toxicity demonstrated the reduced toxicity of the formed intermediates. A plausible mechanism for TC degradation over CFO/CN-PMS-VL was discussed. This work provides a comprehensive guide for heterojunction photocatalytic activation of PMS for efficient micropollutant degradation.

Growth and stabilization of high-concentration metallic 1T-phase MoS2 as a high-performance l-cysteine electrochemical sensor by electron injection engineering

MoS2 is an attractive electrochemical sensing electrode material for the detection of biomolecule because of its adjustable band gap, large surface area, and unique electrochemical characteristics. However, the poor catalytic and electrical conductivity of the semiconductor 2H-phase MoS2 and the phenomenon of restacking during electrochemical use hinder its sensing application. Herein, electron injection engineering is employed for the formation and stabilization of high-concentration metal 1T-phase MoS2 nanosheets on ionic liquid-functionalized carbon nanotubes (CNTs-IL). The increase of MoS2 concentration in the metal 1T phase significantly accelerates electron transfer kinetics. The in-situ growth method results in a tightly interfaced coupling effect, thereby substantially shortening the electron transport pathway and decreasing interfacial transmission impedance. In addition, the sulfur defects on the surface of MoS2 as the anchoring point of sulfhydryl groups promote the enrichment of thiols on the surface of the material and reduce the reaction barrier for sulfhydryl oxidation, thereby improving the catalytic performance. The prepared CNTs-IL-MoS2/SPE biosensor shows excellent l-cysteine sensing performance by electrochemical detection.

Biochars from waste as an additive material in anaerobic co-digestion: Characterization and application in batch and semi-continuous systems

The conversion of organic waste into energy through anaerobic digestion (AD) is a profitable and environmentally friendly strategy. Enhancing the process is crucial for optimizing and maximizing biogas and methane production. To achieve this, various strategies can be employed, such as anaerobic co-digestion (co-AD) and the use of biochar. Biochar aids in process stability, provides buffering capacity, mitigates inhibitory toxins, immobilizes microorganisms, facilitates microbial colonization, and accelerates electron transfer between microorganisms. This study aimed to produce biochar from different wastes and pyrolysis temperatures and to investigate its use as an additive material in the co-AD of fruit and vegetable waste (FVW) and laying chicken manure (LCM) in batch and semi-continuous systems. Thermogravimetric analysis (TGA) and differential scanning calorimetry were performed to determine the pyrolysis temperature for biochar production, defining temperatures of 450 and 550 °C. A biochemical methane potential (BMP) test was conducted in 120 mL reactors (working volume) with the addition of 10 g/L of biochar from FVW, LCM, and wood pruning waste (WPW). WPW450 biochar showed the highest fixed carbon content, rough surface, and deep porous structure, factors that contributed to a 28 % increase in methane production compared to the control. Semi-continuous tests were conducted in 50 L reactors (working volume) using a reduced dosage (1 g/L) of WPW450 biochar, providing process stability and better biogas quality, resulting in a 31 % increase in methane production. The reduction in biochar dosage did not negatively impact the semi-continuous system, which showed a 74 % higher methane yield compared to the batch system. The results of this study highlight the importance of biochar addition to increase methane production in the co-AD of FVW and LCM at different scales, as well as the study of different biomasses and temperatures for biochar production.

Molecularly tailored bifunctional nano-overlayers for efficient and stable inverted perovskite solar cells

Triple cation perovskite solar cells (PSCs) have made remarkable progress in power conversion efficiency (PCE), which is also related to the interface regulation layers between the active layer and electron transport layer (ETL). The ionic nature of the perovskite lattice has enabled approaches to passivate molecular defects through the interaction of functional groups. Herein, a passivator OXD-7 is introduced as a modified layer to passivate surface defects and accelerate electron transfer. It has been observed that OXD-7 can alleviate the micro-strain of the perovskite thin films through intermolecular bonding, which suppresses the iodide vacancy on the perovskite surface. Additionally, the OXD-7 reduces the surface energy of the perovskite films and inhibits the formation of δ-FAPbI3 on the surface of perovskite film. Consequently, the resulting devices demonstrate improved fill factor and device stability. Under optimal fabrication conditions, triple cation mixed perovskite solar cells with an inverted structure achieve a PCE of 23.83%.

Droplet microreactor continuous synthesis of hierarchical Rh on CdZnS snowflakes for enhanced photocatalytic hydrogen evolution

Promising droplet microreactor-cation exchange strategy is utilized to construct the unique Rh hierarchical structure (RhHS) and Rh nanoclusters (RhNCs) on CdZnS (CZS) snowflakes. The fabricated RhHS/RhNCs/CZS achieves an optimal hydrogen evolution activity of 926.0μmol h−1 g−1, which is 5.9 and 10.5 folds enhancement that of CZS and CdS, respectively. The enhanced activity for H2 generation can be attributed to the RhHS/RhNCs (accelerating electron transfer), as well as the hierarchical structure of RhHS and CZS, which enhances reflection–absorption of visible light. Theoretical calculations reveal that Rh species can serve as new H* generation-release sites, reducing the energy barrier for hydrogen evolution. Notably, in situ Raman confirmed the Rh (Rh-H) and S (S-H) two main active sites for proton reduction during hydrogen generation. This paper provides a novel approach to constructing hierarchical structure photocatalyst (RhHS/RhNCs/CZS) for enhanced photocatalytic H2 production.

Enhanced ethanol gas sensing performance of Ag/SnO2 composites

A simple hydrothermal method was adopted to synthesize rectangular block-shaped SnO2 nanomaterials loaded with different amounts of Ag. The structural composition, morphology and chemical state of the nanomaterials were systematically investigated using XRD, SEM, TEM and XPS analysis. The gas sensing performance to ethanol was comprehensively evaluated by testing key parameters including gas response, optimal operating temperature, response-recovery time, and selectivity. The result demonstrates that the Ag/SnO2 composite, compared to pure SnO2, exhibits enhanced efficiency in detecting ethanol. The gas sensor fabricated by the sample Ag/SnO2-2 had a response of up to 80 for 200 ppm ethanol at 300℃. Moreover, the response time (reduced from 52 s to 29 s) and the selectivity were significantly improved. The superior gas sensing performance of Ag/SnO2 is attributed to the generation of highly active sites from Ag ion loading, accelerated electron transfer processes, and modulation of Schottky heterojunctions. In summary, this work demonstrates an effective strategy to improve the gas sensing performance of SnO2-based sensors by Ag loading.

Polymer tethering strategy modified ZIF67 derived cobalt-confined nanocage for norfloxacin degradation: Tailored reactive sites and beneficial local microenvironment

The refined state of reactive sites and their local microenvironment largely determined the reaction performance of catalyst. Herein, we constructed hollow cobalt-confined carbon nanocage (Co-NC@Co/C-x) with rich surface pyridinic N and more exposed tailored Co sites through cobalt-incorporated polymer tethering strategy modified ZIF67 and later thermal depolymerization. Such features facilitate rapid surface enrichment of contaminants, accelerated electron transfer and enhance the availability of unpaired electron oxygen of metallic cobalt, demonstrating exceptional efficiency in Norfloxacin degradation (NFX, 97.7 % within 20 min, kobs = 0.528 min−1) with a significantly lower activation energy of 6.39 KJ mol−1. Mechanistic investigations prove the promotive interplay of peroxymonosulfate with reactive sites and elucidate the dominant role of non-free radicals 1O2 for NFX degradation. The theoretical calculation showcases that unpaired-electron surface oxygen of metallic cobalt induces the impurity cleavage of the O-O bond, triggering the promotive generation of 1O2. Co-NC@Co/C-6 samples exhibit robust NFX degradation across different aqueous matrices, demonstrating cyclic stability and universal degradation performance against various pollutants, and flowing degradation experiments and immobilized recyclable monolith fiber-like bobbles experiments further underline the green recovery and practical potential in wastewater treatment.

Construction of hollow core-shell ZnO@Co3O4 p-n heterojunction for CO2 cycloaddition under visible light irradiation

In comparison to a single semiconductor, constructing p-n heterojunctions represents an efficient strategy for enhancing photocatalytic activity because of their advantages in accelerating charge separation and promoting photoabsorption. Herein, we propose a novel metal–organic framework (MOF)-assisted and controlled pyrolysis strategy for constructing a hollow core-shell p-n heterojunction photocatalyst ZnO@Co3O4. It is worth noting that the hollow core-shell heterojunction not only provides abundant active sites but also significantly facilitates the separation of photogenerated charge carriers and accelerates electron transfer. Benefiting from the above advantages, the optimized ZnO@Co3O4(400,2), obtained by pyrolysis at 400 ℃ for 2h using Zn-MOF@Co-MOF as a precursor, exhibits high activity for the cycloaddition of CO2 and epichlorohydrin, resulting in a 94% yield of 4-(chloromethyl)-1, 3-dioxolan-2-one under 1bar CO2 pressure and visible light irradiation for 2h, which is significantly superior to those of ZnO(400,2) (5%), Co3O4(400,2) (38%), and the physically mixed counterparts (55%). This work provides insightful guidance for designing efficient photocatalysts aimed at CO2 cycloaddition, thereby achieving solar to high-value-added chemical conversion efficiencies.

Charge transfer optimization: role of Cu-graphdiyne/NiCoMoO4 S-scheme heterojunction and Ohmic junction

The effective separation ability of photogenic support plays a crucial role in catalytic hydrogen production. The establishment of heterojunction structure is an effective means to overcome the limited carrier separation ability of some single catalysts. In this paper, Cu, Graphdiyne (GDY) and NiCoMoO4 were successfully coupled to construct a composite photocatalyst NCY-15%. The addition of sheet GDY effectively prevented the aggregation of NiCoMoO4, increased the number of active sites, and enhanced the light-trapping ability of the composite catalyst. The synergistic interaction of S-scheme heterojunction and Ohmic junction heterojunctions between Cu, GDY and NiCoMoO4 provides a unique transfer pathway for electrons, facilitating the rapid separation of photogenerated carriers and accelerating electron transfer, while retaining electrons with strong reducing capacity to participate in hydrogen production, thereby increasing the hydrogen evolution rate. This provides a new way for the development of GDY based photocatalysts.

Electrocatalysis of Co/CoxOy nanofilms supported by synchronously nitrogen-doped Ketjenblack carbon towards oxygen reduction reaction

Developing a highly active and stable non-precious metal catalyst for oxygen reduction reaction (ORR) is of great practical significance for advancing fuel cell technology. In this work, a continuous two-step hydrothermal reaction followed by high temperature pyrolysis were employed to achieve in situ N-doping preferentially into Ketjenblack carbon (KB-N) and composite of KB-N and Co/CoxOy nanofilms (Co/CoxOy-NFs) as Co/CoxOy-NFs@KB-N. The N-doped state strongly affects the ORR activity of catalyst. All prepared Co/CoxOy-NFs@KB-N catalysts exhibit observably improved ORR activity compared with the basal KB-N and N-doped Co/CoxOy-NFs, in which the optimal Co/CoxOy-NFs@KB-N catalyst demonstrate the positive Eonset (0.864 V) and E1/2 (0.788 V) vs. RHE, the low Tafel slope (69.27 mV dec−1), implying quick ORR kinetics. And, the Co/CoxOy-NFs@KB-N catalyst exhibits highly electrochemical durability. The KB-N substrate can purify Co valence in CoO component, promote amorphization of CoO crystalline structure and enhance the interaction between Co/CoxOy-NFs and KB-N in Co/CoxOy-NFs@KB-N catalyst. Thus electronic effect, structural effect and synergistic effect can strengthen O2 adsorption, provide enough adsorbed sites and accelerate electron transfer, resulting in prominent ORR performance of Co/CoxOy-NFs@KB-N catalyst.