Xiong He

Herein, we functionalized CoPc with –SO ₃ H (CoPcTs) to tailor its electronic structure, then integrated it with BiVO ₄ for PEC water splitting. This regulation enhances interface coupling, Co-site activity, and overall PEC performance.

Constructing heterojunction interfaces represents an effective approach to designing high-performance electrocatalysts for water oxidation, yet realizing practical heterostructures presents significant challenges. Herein, we have successfully developed and fabricated a novel MoO₃/NiFe LDH heterojunction material through an efficient one-pot ultrasound-assisted hydrothermal synthesis strategy. The as-prepared MoO₃/NiFe LDH exhibits outstanding electrocatalytic performance for oxygen evolution, achieving a low overpotential of merely 234 mV to drive 50 mA cm⁻² current density, while showing excellent operational durability with minimal potential variation following continuous operation for 100 hours under identical current conditions. The ultrasonic treatment facilitates the formation of a dense, coral reef-inspired nanostructure with uniform morphology, substantially increasing the available catalytic surface area while creating abundant accessible active centers. Furthermore, the heterojunction interface between MoO₃ and NiFe LDH facilitates efficient interfacial electron transfer, thereby accelerating the OER kinetics. This study offers an innovative and scalable approach for constructing heterojunction electrocatalysts, offering new ideas for the logical design of advanced and innovative materials for energy conversion applications.

This study deciphers the anionic modulation mechanism of halide ions (F⁻/Cl⁻) in cobalt-based hydroxides for oxygen evolution reaction (OER). Phase-pure Co(OH)₂, Co(OH)F, and Co₂(OH)₃Cl were fabricated via substrate-independent hydrothermal synthesis to eliminate conductive support interference. Electrocatalytic evaluation on glassy carbon electrodes demonstrates fluoride’s superior regulatory capability over chloride. X-ray photoelectron spectroscopy (XPS) analyses revealed that F⁻ incorporation induces charge redistribution through Co → F electron transfer, optimizing the electronic configuration via ligand effects. F⁻ incorporation simultaneously guided the anisotropic growth of 1D nanorods and reduced surface energy, thereby enhancing the wettability of Co(OH)F. The engineered Co(OH)F catalyst delivers exceptional OER performance: 318 mV overpotential at 10 mA/cm² in 1 M KOH with 94% current retention over 20 h operation. This study provides a synthetic strategy for preparing pure-phase Co(OH)F and compares halide ions’ effects on enhancing OER activity through electronic structure modulation and morphological control of basic cobalt salts.

This study presents a novel approach to enhance photoelectrochemical (PEC) water oxidation by integrating cobalt phthalocyanine (CoPc) with bismuth vanadate (BVO) via a direct solvothermal method. The as-prepared BVO@CoPc photoanode demonstrated a photocurrent density of 4.0 mA cm⁻² at 1.23 V vs. RHE, which is approximately 3.1 times greater than that of the unmodified BVO, and has superior stability. The incident photon-to-current conversion efficiency (IPCE) of the BVO@CoPc photoanode reaches an impressive value of 81%, accompanied by significant enhancements in charge injection efficiency. This excellent performance can be ascribed to the enhanced hydrophilicity with the BVO/CoPc interface engineering, which facilitates interfacial interaction between the electrode and electrolyte, accelerates photogenerated charge carrier transfer and separation. Furthermore, compared to the immersion and drop-casting methods, the BVO@CoPc-S composite photoanode prepared via the solvothermal method exhibits a significant improvement in interfacial contact and surface hydrophilicity. These findings highlight the potential of the strategy based on interfacial hydrophilicity modification to overcome key limitations in PEC water splitting, providing a pathway to more efficient and durable photoanode design.

The oxygen evolution reaction (OER), which involves a four-electron transfer and slow kinetics, requires an efficient catalyst to overcome the high energy barrier for high-performance water electrolysis. In this paper, a novel Ni₃S₂@V-NiFe(III) LDH/NF catalyst was prepared via a facile two-step hydrothermal method. The constructed heterostructure of Ni₃S₂@V-NiFe(III) LDH increases the specific surface area and regulates the electronic structure. Furthermore, the introduction of the V element forms an electron transport chain of Ni-O-Fe-O-V-O-Ni, which optimizes the binding energy between metal active sites and oxygen evolution reaction intermediates, accelerates electron transfer, and improves self-reconstruction. With this dual regulation strategy, Ni₃S₂@V-NiFe(III) LDH/NF exhibits exceptional OER performance with an overpotential of 280 mV at 100 mA/cm² and a Tafel slope of 45.4 mV/dec. This work develops a dual regulation strategy combining heterostructure formation and the doping effect, which are beneficial in the design of efficient OER catalysts.

Energy and the environment are the foundations of modern human society

Bismuth vanadate (BVO) is regarded as an exceptional photoanode material for photoelectrochemical (PEC) water splitting, but it is restricted by the severe photocorrosion and slow water oxidation kinetics. Herein, a synergistic strategy combined with a Co₃(HPO₄)₂(OH)₂ (CoPH) cocatalyst and an Al₂O₃ (ALO) passivation layer was proposed for enhanced PEC performance. The CoPH/ALO/BVO photoanode exhibits an impressive photocurrent density of 4.9 mA cm⁻² at 1.23 V_RHE and an applied bias photon-to-current efficiency (ABPE) of 1.47% at 0.76 V_RHE. This outstanding PEC performance can be ascribed to the suppressed surface charge recombination, facilitated interfacial charge transfer, and accelerated water oxidation kinetics with the introduction of the CoPH cocatalyst and ALO passivation layer. This work provides a novel and synergistic approach to design an efficient and stable photoanode for PEC applications by combining an oxygen evolution cocatalyst and a passivation layer.

Three-dimensional porous carbon materials with moderate heteroatom-doping have been extensively investigated as promising electrode materials for energy storage. In this study, we fabricated a 3D cross-linked chitosan-dicyandiamide-VOSO₄ hydrogel using a polymerization process. After pyrolysis at high temperature, 3D porous VO_x/N-doped carbon nanosheet hybrids (3D VNCN) were obtained. The unique 3D porous skeleton, abundant doping elements, and presence of VO_x 3D VNCN pyrolyzed at 800 °C (3D VNCN-800) ensured excellent electrochemical performance. The 3D VNCN-800 electrode exhibits a maximum specific capacitance of 408.1 F·g⁻¹ at 1 A·g⁻¹ current density and an admirable cycling stability with 96.8% capacitance retention after 5000 cycles. Moreover, an assembled symmetrical supercapacitor based on the 3D VNCN-800 electrode delivers a maximum energy density of 15.6 Wh·Kg⁻¹ at a power density of 600 W·Kg⁻¹. Our study demonstrates a potential guideline for the fabrication of porous carbon materials with 3D structure and abundant heteroatom-doping.

The development of low-cost and high-performance bifunctional electrocatalysts for overall water splitting is still challenging. Herein, we employed a facile electrodeposition method to prepare bifunctional cobalt phosphide for overall water splitting. The needle-like cobalt phosphide (Co-P-1) nanoarray is uniformly distributed on nickel foam. Co-P-1 exhibits excellent electrocatalytic activity for hydrogen evolution reaction (HER, 85 mV at 10 mA/cm², 60 mV/dec) and oxygen evolution reaction (OER, 294 mV at 50 mA/cm², 60 mV/dec). The cell-voltage of 1.60 V is found to achieve the current density of 10 mA/cm² for overall water splitting in the two-electrode system, comparable to that of previously reported Pt/C/NF||RuO₂/NF. The excellent electrocatalytic performance can be attributed to the needle-like structure with more active sites, accelerated charge transfer and evolved bubbles’ release. This work can provide new approach to the development of a bifunctional electrocatalyst for overall water splitting.

Lithium batteries incorporating LiFePO₄ (LFP) as the cathode material have gained significant attention in recent research. However, the limited electronic and ionic conductivity of LFP poses challenges to its cycling performance and overall efficiency. In this study, we address these issues by synthesizing a series of LiFePO₄/carbon (LFP/C) composites through low-temperature carbonization coating of LFP in the presence of Coke as the carbon source. The resulting lithium batteries utilizing LFP/C as the cathode material exhibited impressive discharge specific capacities of 148.35 mA·h/g and 126.74 mA·h/g at 0.1 C and 1 C rates, respectively. Even after 200 cycles of charging and discharging, the capacities remained remarkably high, with values of 93.74% and 97.05% retention, showcasing excellent cycling stability. Notably, the LFP/C composite displayed exceptional rate capability, and capacity retention of 99.27% after cycling at different multiplication rates. These findings underscore the efficacy of in situ low-temperature carbonization capping of LFP with Coke in significantly improving both the cycling stability and rate capability of lithium batteries.