Yongde Xia

Indium sulfide is a promising photoactive material for light-induced applications, particularly photoelectrochemical (PEC) water splitting. However, its practical application is limited by photocorrosion, which hinders its long-term efficiency. In this study, we report a hydrothermal synthesis of In-cystine bonded (311)-oriented indium sulfide thin films using a mixed sulfur source of l-cysteine hydrochloride and l-cystine, the latter generated in situ via Fe³⁺-induced oxidation of l-cysteine. Synthesis parameters such as temperature and ramp rate are found to affect the indium-organic complex’s physical and chemical properties such as composition, morphology, thickness, crystal structure, and thereby the PEC performance of the resulting films. The results indicated that thin films synthesized under slow heating conditions (e.g., 160–3 at 160 °C with a ramp rate of 3 °C/min for 6 h; 180–3 at 180 °C with a ramp rate of 3 °C/min for 6 h) exhibited a dominant indium sulfide phase bonded with In-cystine and demonstrated high and stable photocurrent densities of 1.0 and 0.93 mA cm^–2 at −0.2 V vs Ag/AgCl, respectively. In contrast, the fast-heated thin film 160–10 (prepared at 160 °C with a ramp rate of 10 °C/min for 6 h) primarily contained indium-organic complexes with mixed In-cystine and In-cysteine bonding and exhibited a photocurrent density of 0.35 mA cm^–2 at −0.2 V vs Ag/AgCl. Stability testing further revealed that after 2 h of continuous illumination at −0.2 V vs Ag/AgCl, the thin film 160–3 retained 0.75 mA cm^–2, while 180–3 maintained 1.1 mA cm^–2, demonstrating improved resistance to photocorrosion. This work presents an effective strategy for improving the long-term PEC performance of metal sulfide photoelectrodes by introducing In-cystine bonding at their surface, offering a pathway toward more stable and efficient solar-driven water-splitting devices.

A horizontal rotating electrospinning platform continuously spins helical fibre ropes, yielding mats with a markedly more open projected architecture than conventional straight-fibre mats.

Efficient photocatalysts for hydrogen production and pollutant degradation are crucial to address energy and environmental challenges. metal–organic framework (MOF)‐derived Cu _x O/TiO ₂ /C (TCC) composites are synthesized from Cu‐doped NH ₂ ‐MIL‐125(Ti) and their performance in photodegradation of pollutants and photocatalytic hydrogen generation are evaluated. These porous TCC composites demonstrate rapid adsorption capacities and greatly enhance photocatalytic degradation of organic pollutants under visible light, with TCC‐1 achieving complete pollutants removal in 90 min due to adsorption and photocatalysis. Moreover, these Cu _x O/TiO ₂ /C composites exhibit superior photocatalytic hydrogen evolution performance, and TCC‐2 achieves the highest hydrogen production rate of 2339 μmol g ⁻¹ h ⁻¹ , 13 times greater than TiO ₂ /C. The enhanced activity is attributed to the formation of type‐II band alignment between the coexisted anatase and rutile TiO ₂ phases, the presence of Cu ₂ O/CuO heterojunctions that facilitate p–n charge separation, and Cu ⁰ clusters as electron sinks to accelerate proton reduction. Porous carbon boosts adsorption and also provides rapid electron transport pathways. Additionally, the coexistence of multiple Cu species (Cu ²⁺ /Cu ⁺ ) facilitates reversible redox shuttling, suppressing electron–hole recombination. The synergistic effects of these structural and electronic features lead to superior hydrogen generation and pollutant degradation activity of TCC composites, demonstrating the promise of MOF‐derived photocatalysts for sustainable energy and environmental applications.

Indium sulfide thin films play a crucial role in photoelectrochemical (PEC) water splitting, offering promising strategies to mitigate energy shortages and global warming. In this study, indium sulfide thin films were synthesized via a hydrothermal method, and the effects of sulfur precursors—L-cysteine (LC) and L-cysteine hydrochloride (LCHCl)—along with hydrothermal temperature ramp rates (3 and 10 °C min⁻¹) on their crystallographic orientation, morphology, and thickness were investigated. The findings revealed that films synthesized with LC predominantly exhibited the (440) facet, while those synthesized with LCHCl had the (311) facet. Additionally, films produced at 3 °C min⁻¹ were thicker than those synthesized at 10 °C min⁻¹. The film (LC-IS-10) synthesized at 10 °C min⁻¹ using LC achieved a photocurrent density of 3.7 mA cm⁻² at −0.2 V vs. Ag/AgCl, which outperformed that of LCHCl-synthesized film (LCHCl-IS-10) at the same heating rate (2.6 mA cm⁻²) and those of the films synthesized at 3 °C min⁻¹ (LC-IS-3: 0.7 mA cm⁻² and LCHCl-IS-3: 2 mA cm⁻²). 2-Hour photocurrent stability assessments indicated that LC-synthesized films (LC-IS-3: 1 mA cm⁻², LC-IS-10: 670 μA cm⁻²) exhibited superior stability to the LCHCl-synthesized films (LCHCl-IS-10: 90 μA cm⁻², LCHCl-IS-3: 33 μA cm⁻²). This improved stability was attributed to their (440) facet, which was structurally more compact and symmetric and exhibited reduced sulfur exposure than the less ordered (311) facet. Although the LC-IS-3 film had the lowest photocurrent density, it showed enhanced stability, owing to the thickness alteration caused by the oxidation of surface S²⁻ species. This research provides insights for optimizing material design in PEC water-splitting applications, advancing sustainable energy solutions.

Developing robust active electrocatalysts from readily available earth‐abundant elements for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR) remains an unresolved challenge. Herein, Ti₃C₂T_x MXene‐containing metal–organic framework‐derived CoP nanocomposite electrocatalysts are successfully prepared by phosphidation of in situ‐produced ZIF‐67/MXene composite precursor at various heat treatment temperatures. The obtained nanocomposite catalysts are characterized by X‐ray diffraction, Brunauer–Emmett–Teller, X‐ray photoelectron spectroscopy, field emission‐scanning electron microscope/energy dispersive X‐ray spectroscopy (EDS), and high‐resolution transmission electron microscopy/EDS. In the produced composites, Ti₃C₂T_x MXene functions as a supportive substrate to facilitate mass transfer, as well as ion transport, and to improve electrical conductivity. Moreover, the introduction of MXene into the heterostructured CoP@C/Ti₃C₂T_x enables it to expose and provide extra active sites for electrochemical reactions. The as‐prepared CoP@C/MXene‐360 (abbreviated as CPMX‐360) nanocomposite is a promising trifunctional electrocatalyst toward OER, HER, and ORR. CPMX‐360 exhibits excellent electrocatalytic activity with an overpotential of 235 mV at 10 mA cm⁻² in OER, an overpotential of 220 mV at −10 mA cm⁻² in HER, and an E_onset and E_1/2 of 0.82 and 0.74 V in ORR, respectively. This research provides a viable method to develop nonprecious trifunctional electrocatalyst via phosphidation of metal–organic framework and MXene with excellent performance for OER, HER, and ORR.

Vanadium dioxide (VO₂) is a key coating component for smart devices, especially in smart windows, due to its excellent thermochromic properties and metal-insulating transformation. In this study, we investigate the influence of different annealing on the VO₂ thin films prepared by a sol-gel technique combined with spin-coating and compare the changes in morphology, structure, and optical properties. Of the two types of VO₂ (M) films obtained by one-step annealing at 700 °C and two-step annealing at 500 and 700 °C, the two-step annealed samples formed an intermediate phase VO₂ (B), which allowed them to exhibit higher purity and better crystallinity than those of the one-step annealed samples. An in-situ XRD study confirmed that the higher purity and better crystallinity enabled the resulting VO₂ thin films to lower the phase transition temperature, where the phase transition occurred by 5 °C earlier upon heating and about 10 °C upon cooling. As a result, the infrared and solar modulation capabilities were improved by 87 and 127%, respectively, while the high visible transmittance of the samples essentially remained unchanged. This study has demonstrated that proper annealing can refine the structures of VO₂ thin films and enhance their optical properties.

A porous CeO₂ catalyst produced via a simple and low temperature approach achieves a high dimethyl carbonate formation rate of 14.8 mmol g⁻¹ h⁻¹ at 5.0 MPa and 140 °C due to the superimposition of a number of properties of the catalyst.

Photocatalysis is an environmentally friendly technology for the utilizations of solar energy and has garnered significant attention in both scientific and industrial sectors. Developing cost‐effective semiconductive materials is the core issue in photocatalysis. Bismuth‐based metal‐organic frameworks (Bi‐MOFs) have emerged as attractive candidates in various photocatalytic applications, and Bi‐MOFs derivatives further expand and consolidate their promising potential in the realm of photocatalysis. Various modification strategies including in‐situ tailoring or external doping, as well as meticulous design and selection of metal nodes and organic linkers allow for fine control over the surface multifunctionality in Bi‐MOF‐based and derived photocatalytic composites with adjustable energy band structures and enhanced photocatalytic performance. In this review, the recent progress in the synthesis of diverse Bi‐MOFs‐based materials, Bi‐MOFs derivatives, and their Bi‐containing semiconductive composites were systemically analyzed and reviewed. The state‐of‐the‐art research progresses in the applications of Bi‐MOFs and derivatives, as well as composites in photocatalytic water splitting for hydrogen production, photodegradation of organic pollutants, and photocatalytic carbon dioxide reduction are comprehensively summarized. The relationships between structures, properties, and photocatalytic performance of Bi‐based semiconductive composites are discussed in detail. In addition, the perspectives and future challenges on Bi‐MOFs‐based and derived materials for photocatalytic applications are also offered.

The development of effective bifunctional electrocatalysts that can realize water splitting to produce oxygen and hydrogen through oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is still a great challenge to be addressed. Herein, we report a simple and versatile approach to fabricate bifunctional OER and HER electrocatalysts derived from ZIF67/MXene hybrids via sulfurization of the precursors in hydrogen sulfide gas atmosphere at high temperatures. The as-prepared CoS@C/MXene nanocomposites were characterized using a series of technologies including X-ray diffraction, gas sorption, scanning electronic microscopy, transmission electronic microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The synthesized CoS@C/MXene composites are electrocatalytically active in both HER and OER, and the CSMX-800 composite displayed the highest electrocatalytic performance towards OER and HER among all the produced samples. CSMX-800 exhibited overpotentials of 257 mV at 10 mA cm⁻² for OER and 270 mV at 10 mA cm⁻² for HER. Moreover, it also possesses small Tafel slope values of 93 mV dec⁻¹ and 103 mV dec⁻¹ for OER and HER, respectively. The enhanced electrocatalytic performance of the MXene-containing composites is due to their high surface area, enhanced conductivity, and faster charge transfer. This work demonstrated that CoS@C/MXene based electrocatalyst has great potential in electrochemical water splitting for hydrogen production, thus reducing carbon emissions and protecting the environment.