Efficient and Stable MoS2/CdSe/NiO Photocathode for Photoelectrochemical Hydrogen Generation from Water

Direct Z-scheme heterojunction impregnated MoS2-NiO-CuO nanohybrid for efficient photocatalyst and dye-sensitized solar cell

In this present work, the preparation of ternary MoS2-NiO-CuO nanohybrid by a facile hydrothermal process for photocatalytic and photovoltaic performance is presented. The prepared nanomaterials were confirmed by physio-chemical characterization. The nanosphere morphology was confirmed by electron microscopy techniques for the MoS2-NiO-CuO nanohybrid. The MoS2-NiO-CuO nanohybrid demonstrated enhanced crystal violet (CV) dye photodegradation which increased from 50 to 95% at 80 min; The degradation of methyl orange (MO) dye increased from 56 to 93% at 100 min under UV-visible light irradiation. The trapping experiment was carried out using different solvents for active species and the Z-Scheme photocatalytic mechanism was discussed in detail. Additionally, a batch series of stability experiments were carried out to determine the photostability of materials, and the results suggest that the MoS2-NiO-CuO nanohybrid is more stable even after four continuous cycles of photocatalytic activity. The MoS2-NiO-CuO nanohybrid delivers photoconversion efficiency (4.92%) explored efficacy is 3.8 times higher than the bare MoS2 (1.27%). The overall results indicated that the MoS2-NiO-CuO nanohybrid nanostructure could be a potential candidate to be used to improve photocatalytic performance and DSSC solar cell applications as well.

A microfluidic cathodic photoelectrochemical biosensor chip for the targeted detection of cytokeratin 19 fragments 21-1

A microfluidic chip integrated with a microelectrode and a cathodic photoelectrochemical (PEC) biosensor for the ultrasensitive detection of non-small cell lung cancer cytokeratin fragments based on a signal amplification strategy was designed. The mechanism for signal amplification is developed based on the p-n junction of AgI/Bi₂Ga₄O₉, with dissolved O₂ as an electron acceptor to produce the superoxide anion radical (˙O₂^-) as the working microelectrode. By combining this with a novel superoxide-dismutase-loaded honeycomb manganese oxide nanostructure (SOD@hMnO₂) as the co-catalyst signal amplification label, ˙O₂^- can be catalyzed by SOD via a disproportionation reaction to produce O₂ and H₂O₂; then, hMnO₂ is able to trigger the decomposition of H₂O₂ to generate O₂ and H₂O. Therefore, the increased O₂ promotes the separation of electron-hole pairs via consuming more electrons, leading to an effective enhancement of the cathodic PEC behavior. Under optimum conditions, with the cytokeratin 19 fragments 21-1 (CYFRA 21-1) as the targeted detection objects, the microfluidic cathodic PEC biosensor chip exhibited excellent linearity from 0.1 pg mL^-1 to 100 ng mL^-1, with a detection limit of 0.026 pg mL^-1 (S/N = 3). The exciting thing that this work offers is a new strategy for the detection of other important cancer biomarkers for disease diagnosis and prognosis.

Electrochemical and Photoelectrochemical Properties of Nickel Oxide (NiO) With Nanostructured Morphology for Photoconversion Applications

The cost-effective production of chemicals in electrolytic cells and the conversion of the radiation energy into electrical energy in photoelectrochemical cells (PECs) require the use of electrodes with large surface area, which possess either electrocatalytic or photoelectrocatalytic properties. In this context nanostructured semiconductors are electrodic materials of great relevance because of the possibility of varying their photoelectrocatalytic properties in a controlled fashion via doping, dye-sensitization or modification of the conditions of deposition. Among semiconductors for electrolysers and PECs the class of the transition metal oxides (TMOs) with a particular focus on NiO interests for the chemical-physical inertness in ambient conditions and the intrinsic electroactivity in the solid state. The latter aspect implies the existence of capacitive properties in TMO and NiO electrodes which thus act as charge storage systems. After a comparative analysis of the (photo)electrochemical properties of nanostructured TMO electrodes in the configuration of thin film the use of NiO and analogs for the specific applications of water photoelectrolysis and, secondly, photoelectrochemical conversion of carbon dioxide will be discussed.

NiO nanowires as hole-transfer layer for drastic enhancement of CdSe-sensitized photocathodes

Grass-like NiO nanowires as a hole-transfer layer to improve light capture efficiency and charge transfer rate for a CdSe-sensitized photocathode.

Ferroelectric Materials: A Novel Pathway for Efficient Solar Water Splitting

Over the past few decades, solar water splitting has evolved into one of the most promising techniques for harvesting hydrogen using solar energy. Despite the high potential of this process for hydrogen production, many research groups have encountered significant challenges in the quest to achieve a high solar-to-hydrogen conversion efficiency. Recently, ferroelectric materials have attracted much attention as promising candidate materials for water splitting. These materials are among the best candidates for achieving water oxidation using solar energy. Moreover, their characteristics are changeable by atom substitute doping or the fabrication of a new complex structure. In this review, we describe solar water splitting technology via the solar-to-hydrogen conversion process. We will examine the challenges associated with this technology whereby ferroelectric materials are exploited to achieve a high solar-to-hydrogen conversion efficiency.

Recent Advances in Sensitized Photocathodes: From Molecular Dyes to Semiconducting Quantum Dots

The increasing demand for sustainable and environmentally benign energy has stimulated intense research to establish highly efficient photo-electrochemical (PEC) cells for direct solar-to-fuel conversion via water splitting. Light absorption, as the initial step of the catalytic process, is regarded as the foundation of establishing highly efficient PEC systems. To make full use of visible light, sensitization on photoelectrodes using either molecular dyes or semiconducting quantum dots provides a promising method. In this field, however, there remain many fundamental issues to be solved, which need in-depth study. Here, fundamental knowledge of PEC systems is introduced to enable readers a better understanding of this field. Then, the development history and current state in both molecular dye- and quantum dot-sensitized photocathodes for PEC water splitting are discussed. A systematical comparison between the two systems has been made. Special emphasis is placed on the research of quantum dot-sensitized photocathodes, which have shown superiority in both efficiency and durability towards PEC water splitting at the present stage. Finally, the opportunities and challenges in the future for sensitized PEC water-splitting systems are proposed.

ITO nanoparticle film as a hole-selective layer for PbS-sensitized photocathodes

This study opened a new door to fabricate semiconductor sensitized photocathodes using ITO as the holes transfer layer.

A novel g-C3N4 based photocathode for photoelectrochemical hydrogen evolution

Novel and stable g-C₃N₄ based photocathode was designed and prepared with excellent activity for PEC hydrogen production without external co-catalyst.