In Situ Integration of ReS2/Ni3S2 p-n Heterostructure for Enhanced Photoelectrocatalytic Performance

Incorporating ReS2 Nanosheet into ZnIn2S4 Nanoflower as Synergistic Z-Scheme Photocatalyst for Highly Effective and Stable Visible-Light-Driven Photocatalytic Hydrogen Evolution and Degradation

Inspired by natural photosynthesis, the visible-light-driven Z-scheme system is very effective and promising for boosting photocatalytic hydrogen production and pollutant degradation. Here, a synergistic Z-scheme photocatalyst is constructed by coupling ReS2 nanosheet and ZnIn2S4 nanoflower and the experimental evidence for this direct Z-scheme heterostructure is provided by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and electron paramagnetic resonance. Consequently, such a unique nanostructure makes this Z-scheme heterostructure exhibit 23.7 times higher photocatalytic hydrogen production than that of ZnIn2S4 nanoflower. Moreover, the ZnIn2S4/ReS2 photocatalyst is also very stable for photocatalytic hydrogen evolution, almost without activity decay even storing for two weeks. Besides, this Z-scheme heterostructure also exhibits superior photocatalytic degradation rates of methylene blue (1.7 × 10-2 min-1) and mitoxantrone (4.2 × 10-3 min-1) than that of ZnIn2S4 photocatalyst. The ultraviolet-visible absorption spectra, transient photocurrent spectra, open-circuit potential measurement, and electrochemical impedance spectroscopy reveal that the superior photocatalytic performance of ZnIn2S4/ReS2 heterostructure is mostly attributed to its broad and strong visible-light absorption, effective separation of charge carrier, and improved redox ability. This work provides a promising nanostructure design of a visible-light-driven Z-scheme heterostructure to simultaneously promote photocatalytic reduction and oxidation activity.

ReS2@Au NPs as signal labels quenching steady photocurrent generated by NiCo2O4/CdIn2S4/In2S3 heterojunction for sensitive detection of CYFRA 21-1

In order to achieve rapid and sensitive detection of CYFRA 21-1, a signal-off photoelectrochemical (PEC) immunosensor was devised with NiCo₂O₄/CdIn₂S₄/In₂S₃ heterojunction photoactive materials as sensing platform and ReS₂@Au NPs as the secondary antibody labels amplifying signal based on the energy band-matching cascade structure and double suppression effect. NiCo₂O₄ possessed a faster charge transfer rate due to the abundance of redox electron pairs (Co³⁺/Co²⁺ and Ni³⁺/Ni²⁺). To further improve the PEC properties of NiCo₂O₄ under visible light, CdIn₂S₄ with matching bandgap energy was selected to form heterojunction with NiCo₂O₄ and sensitized with In₂S₃. The proposed heterojunctions with well-matched band structure promoted the transfer of photo-generated carriers and were exploited as signal transducers for immobilization of antibodies and recognition of CYFRA 21-1. Furthermore, a novel urchin-like p-type ReS₂ semiconductor nanostructure functionalized by Au NPs was firstly used as a nanolabel to quench the signal. On the one hand, the Schottky heterojunction generated by ReS₂ and Au NPs could compete with the transducer substrate for both light and electron donors. On the other hand, the large space steric hindrance of ReS₂ prevented contact between the matrix and AA. Subsequently, the sensor was sensitive in a wide range of concentrations for CYFRA 21-1 (0.0001-50 ng/mL), and the detection limit was 0.05 pg/mL.

Ni/Mo Bimetallic-Oxide-Derived Heterointerface-Rich Sulfide Nanosheets with Co-Doping for Efficient Alkaline Hydrogen Evolution by Boosting Volmer Reaction

Molybdenum disulfide (MoS₂ ) is a promising alternative to Pt-based catalysts for electrocatalytic hydrogen evolution reaction (HER) in an acidic environment. However, alkaline HER activity for molybdenum disulfide is limited by its slow water dissociation kinetics. Interface engineering is an effective strategy for the design of alkaline HER catalysts. However, the restricted heterointerfaces of current catalysts have significantly limited their alkaline HER performance. Herein, a novel assembly of cobalt-doped interface- and defect-rich MoS₂ /Ni₃ S₂ hetero-nanosheet anchoring on hierarchical carbon framework for alkaline HER is reported by directly vulcanizing NiMoO₄ nanosheets. In the heterostructure nanosheet, Ni₃ S₂ acts as a water dissociation promoter and MoS₂ acts as a hydrogen acceptor. Density functional theory calculations find that redistribution of charges at the heterointerface can reduce hydrogen adsorption Gibbs free energy (∆G_H* ) and water decomposition energy barrier. The resulting hierarchical electrode with the synergistic effect of both hybrid components shows a low overpotential of 89 mV at -10 mA cm^-2 in 1 m KOH, a Tafel slope as low as 62 mV dec^-1 , and can run at -100 mA cm^-2 for at least 50 h without obvious voltage change. This study provides a potentially feasible strategy for the design of heterostructure-based electrocatalysts with abundant active interfaces.

Construction of heterojunctions between ReS2 and twin crystal ZnxCd1−xS for boosting solar hydrogen evolution

Nanoflower-like ReS₂ anchoring on nanotwins Zn_xCd_1−xS greatly boosts photocatalytic hydrogen evolution rate with 31-times higher than pure phase P-ZCS.

A comparative study of the effects of different TiO2 supports toward CO2 electrochemical reduction on CuO/TiO2 electrode

CuO-based electrodes possess vast potential in the field of CO₂ electrochemical reduction. Meantime, TiO₂ supports show the advantages of being non-toxic, low-cost and having high chemical stability, which render it an ideal electrocatalytic support with CuO. However, different morphologies and structures of TiO₂ supports can be obtained through various methods, leading to the discrepant electrocatalytic properties of CuO/TiO₂. In this paper, three supports, named dense TiO₂, TiO₂ nanotube and TiO₂ nanofiber, were applied to synthesize CuO/TiO₂ electrodes by thermal decomposition, and the performances of the electrocatalysts were studied. Results show that the main product of the three electrocatalysts was ethanol, but the electrochemical efficiency and reaction characteristics are obviously different. The liquid product of CuO/Dense TiO₂ is pure ethanol, however, the current efficiency is rather low owing to the higher resistance of the TiO₂ film. CuO/TiO₂ nanotube shows high conductivity and ethanol can be synthesized at low overpotential with high current efficiency, but the gas products cannot be restricted. CuO/TiO₂ nanofiber has a larger specific surface area and more active sites, which is beneficial for CO₂ reduction, and the hydrogen evolution reaction can be evidently restricted. The yield of ethanol reaches up to 6.4 μmol cm⁻² at −1.1 V (vs. SCE) after 5 h.

Electrocatalytic reduction of CO₂ on three different morphologies of CuO/TiO₂.

Advancing Applications of Black Phosphorus and BP-Analog Materials in Photo/Electrocatalysis through Structure Engineering and Surface Modulation

Black phosphorus (BP), an emerging 2D material semiconductor material, exhibits unique properties and promising application prospects for photo/electrocatalysis. However, the applications of BP in photo/electrocatalysis are hampered by the instability as well as low catalysis efficiency. Recently, tremendous efforts have been dedicated toward modulating its intrinsic structure, electronic property, and charge separation for enhanced photo/electrocatalytic performance through structure engineering. Simultaneously, the search for new substitute materials that are BP-analogous is ongoing. Herein, the latest theoretical and experimental progress made in the structural/surface engineering strategies and advanced applications of BP and BP-analog materials in relation to photo/electrocatalysis are extensively explored, and a presentation of the future opportunities and challenges of the materials is included at the end.

Nanoscale engineering and Mo-doping of 2D ultrathin ReS2 nanosheets for remarkable electrocatalytic hydrogen generation

Two-dimensional (2D) lamellar ReS2 nanosheets are considered a promising electrocatalyst for the hydrogen evolution reaction (HER) but suffer from poor intrinsic conductivity and catalytically inert basal planes. In this work, sub 50 nm hierarchical Mo-doped ReS2 nanospheres consisting of numerous few-layered and defect-rich nanosheets are designed and synthesized as robust and efficient HER catalysts. On the one hand, the small size of the hierarchical structure, the disordered basal planes and the expanded interlayer endow the nanosheets with plentiful defects, thereby resulting in abundant exposed active sites. On the other hand, Mo-doping offers the nanosheets with some electronic benefits of unsaturated electrons, improved intrinsic conductivity, and optimized hydrogen adsorption free energy (ΔGH) of the basal planes. Owing to the synergistic effects, the 10%Mo-ReS2 catalyst exhibits an optimized catalytic activity with striking kinetic metrics of a small Tafel slope of 62 mV dec-1, a low overpotential of 81 mV at 10 mA cm-2, and a long operation stability of 50 h, and its performance is among the best of ReS2-based catalysts. This work provides a new approach for gaining the structural and electronic benefits of ReS2 catalysts by combinational nanoscale engineering and heteroatom doping.

The surface engineering of ReS2 with cobalt for efficient performance in hydrogen evolution under both acid and alkaline conditions

Cobalt-modified rhenium disulfide nanosheets rich in defects, obtained by following an ingenious atom substitution strategy, exhibited boosted HER performance. The 2%-Co doped ReS2 sample was highly efficient in both acid electrolyte (149 mV) and alkaline electrolyte (240 mV), achieving a current density of 10 mA cm-2 as well as superior long-term durability.

Single-Crystal Integrated Photoanodes Based on 4H-SiC Nanohole Arrays for Boosting Photoelectrochemical Water Splitting Activity

Photoelectrochemical (PEC) splitting of water into H₂ and O₂ by direct use of sunlight is an ideal strategy for the production of clean and renewable energy, which fundamentally relies on the exploration of advanced photoanodes with high performance. In the present work, we report that single-crystal integrated photoanodes, that is, 4H-SiC nanohole arrays (active materials) and SiC wafer substrate (current collector), are established into a totally single-crystal configuration without interfaces, which was based on a two-step electrochemical etching process. The as-fabricated SiC photoanode showed a rather low onset potential of -0.016 V vs reversible hydrogen electrode (RHE) and a high photocurrent density of 3.20 mA/cm² vs RHE 1.23 V, which were both superior to those of all reported SiC ones. Furthermore, such a rationally designed photoanode exhibited a fast photoresponse, wide photoresponse wavelength range, and long-term stability, representing its overall excellent PEC performance.