Ling Zan

The microstructure at the interface between the cocatalyst and semiconductor plays a vital role in concentrating photo‐induced carriers and reactants. However, observing the atomic arrangement of this interface directly using an electron microscope is challenging due to the coverings of the semiconductor and cocatalyst. To address this, multiple metal‐semiconductor interfaces on three TiO₂ crystal facets (M/TiO₂─N, where M represents Ag, Au, and Pt, and N represents the 001, 010, and 101 single crystal facets). The identical surface atomic configuration of the TiO2 facets allowed us to investigate the evolution of the microstructure within these constructs using spectroscopies and DFT calculations. For the first time, they observed the transformation of saturated Ti_6c─O bonds into unsaturated Ti_5c─O and Ti_6c─O─Pt bonds on the TiO₂─010 facet after loading Pt. This transformation have a direct impact on the selectivity of the resulting products, leading to the generation of CO and CH₄ at the Ti_6c─O─Pt and Pt sites, respectively. These findings pinpoint the pivotal roles played by the atomic arrangement at the M/TiO₂─N interfaces and provide valuable insights for the development of new methodologies using conventional lab‐grade equipment.

The construction of Z‐scheme photocatalyst materials mimicking the natural photosynthesis system provides many advantages, including increased light harvesting, spatially separated reductive and oxidative active sites and strong redox ability. Here, a novel Bi₂S₃ nanorod@In₂S₃ nanoparticle heterojunction photocatalyst synthesized through one‐pot hydrothermal method for Cr⁶⁺ reduction is reported. A systematic investigation of the microstructural and compositional characteristics of the heterojunction catalyst confirms an intimate facet coupling between (440) crystal facet of In₂S₃ and (060) crystal facet of Bi₂S₃, which provides a robust heterojunction interface for charge transfer. When tested under visible‐light irradiation, the Bi₂S₃–In₂S₃ heterojunction photocatalyst with 15% Bi₂S₃ loading content achieves the highest Cr⁶⁺ photoreduction efficiency of nearly 100% with excellent stability, which is among the best‐reported performances for Cr⁶⁺ removal. Further examination using optical, photoelectrochemical, impedance spectroscopy, and electron spin resonance spectroscopy characterizations reveal greatly improved photogenerated charge separation and transfer efficiency, and confirm Z‐scheme electronic structure of the photocatalyst. The Z‐scheme Bi₂S₃–In₂S₃ photocatalyst demonstrated here presents promise for the removal of highly toxic Cr⁶⁺, and could also be of interest in photocatalytic energy conversion.

Rapidly electrons transferring of noble metal‐free electron mediator NiS modifying In ₂ S ₃ photocatalysts were synthesized through a one‐pot hydrothermal method. Light with longer wavelength scope and stronger intensity can be absorbed and achieving more rapidly electrons transportation speed. PL and photocurrent spectra demonstrating that NiS‐In ₂ S ₃ composites have higher charge carrier separation efficiency. HRTEM revealed that NiS and In ₂ S ₃ were contacted in nano size and have intimate contact with each other. XPS further proved there has an influence of the banding energy between NiS and In ₂ S ₃ . 10 % content sample achieving complete removal of Cr ⁶⁺ with a trace photocatalyst concertation (0.2 mg/mL) within 30 min which was 3 times higher than pure In ₂ S ₃ . The proper mechanism was proposed that In ₂ S ₃ was excited by visible light to produce electron‐hole pairs, and NiS acted as a light absorbing intensifier and electron trapper conducting electrons from the In ₂ S ₃ conduction band to the surface of composites and then reacting with the active species, thus improving the charge carrier separation efficiency and photocatalytic activity

Compositing nanoparticles photo-catalyst with enormous surface areas metal–organic framework (MOF) will greatly improve photocatalytic performances. Herein, WO₃nanoparticles are partly embedded into pores of MIL-101 or only supported on the outside of representative MIL-101, which were defined as embedded structure WO₃@MIL-101@WO₃and coating structure WO₃&MIL-101 respectively. Different pH, concentration and loading percentage were researched. XRD, TEM and BET were carried to analyze the composites. Compared with the pristine WO₃, all WO₃loaded MOF nanocomposites exhibited remarkable enhancing for the efficiency of photocatalytic degradation methylene blue under visible light. Their activity of the same loading percentage WO₃in embedded structure and coating structure have increased for 9 and 3 times respectively compared with pure WO₃. The WO₃@MIL-101@WO₃has 3 times higher efficiency than WO₃&MIL-101, because the shorter electron-transport distance can make a contribution to electron–hole separation. The further mechanism involved has been investigated by radical quantify experiment, XPS and photoluminescence spectroscopy.

Herein, anatase TiO₂ with different percentages of exposed {001} and {101} facets was prepared, and subsequently, Ag and MnO_x were co-loaded on these TiO₂ facets through a classical photodeposition method; the loaded TiO₂ samples were labeled as Ag–TiO₂–MnO_x (N%), where N% denotes the percentage of the exposed {001} facets. The as-prepared samples were analyzed via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS), and the photocatalytic reduction of CO₂ was carried out. The results showed that Ag–TiO₂–MnO_x (40%) exhibited the highest photocatalytic activity among the other dual-loaded samples and pure TiO₂. The XPS spectra demonstrated that Ti–O–Mn and Ti–O–H bonds were formed at the interfaces of the cocatalyst-TiO₂. The PL and VB spectra revealed that the chemical bond (Ti–O–Mn) at the Ag–TiO₂–MnO_x (40%) interface greatly increased the hole mobility rate and the photoinduced carrier separation efficiency that resulted in higher catalytic activity for the photoreduction of CO₂.

The proposed growth mechanism of Ag NPs during PAg–TiO ₂ (A) and SAg–TiO ₂ (B) preparation processes.

Three-dimensional macroporous graphene-based Li₂FeSiO₄ composites (3D-G/Li₂FeSiO₄/C) were synthesized and tested as the cathode materials for lithium-ion batteries. To demonstrate the superiority of this structure, the composite’s performances were compared with the performances of two-dimensional graphene nanosheets-based Li₂FeSiO₄ composites (2D-G/Li₂FeSiO₄/C) and Li₂FeSiO₄ composites without graphene (Li₂FeSiO₄/C). Due to the existence of electronic conductive graphene, both 3D-G/Li₂FeSiO₄/C and 2D-G/Li₂FeSiO₄/C showed much improved electrochemical performances than the Li₂FeSiO₄/C composite. When compared with the 2D-G/Li₂FeSiO₄/C composite, 3D-G/Li₂FeSiO₄/C exhibited even better performances, with the discharge capacities reaching 313, 255, 215, 180, 150, and 108 mAh g^–1 at the charge–discharge rates of 0.1 C, 1 C, 2 C, 5 C, 10 C and 20 C (1 C = 166 mA g^–1), respectively. The 3D-G/Li₂FeSiO₄/C composite also showed excellent cyclability, with capacity retention exceeding 90% after cycling for 100 times at the charge–discharge rate of 1 C. The superior electrochemical properties of the 3D-G/Li₂FeSiO₄/C composite are attributed to its unique structure. Compared with 2D graphene nanosheets, which tend to assemble into macroscopic paper-like structures, 3D macroporous graphene can not only provide higher accessible surface area for the Li₂FeSiO₄ nanoparticles in the composite but also allow the electrolyte ions to diffuse inside and through the 3D network of the cathode material. Specially, the fabrication method described in this study is general and thus should be readily applicable to the other energy storage and conversion applications in which efficient ionic and electronic transport is critical.

We firstly demonstrate the opposite photocatalytic activity orders of low-index facets of anatase TiO₂ in the liquid phase for rhodamine B (RhB) photocatalytic degradation and in the gaseous phase for the photoreduction of CO₂ to CH₄. The photocatalytic activity order in the liquid phase for RhB photocatalytic degradation is revealed as {001} > {101} > {010}, whereas the photocatalytic activity order {010} > {101} > {001} is found in the gaseous phase for the photoreduction of CO₂ to CH₄. The atomic arrangement of the different facets, UV-vis diffuse reflectance spectra, photoluminescence spectra and attenuated total reflectance Fourier transform infrared spectroscopy analysis show that the photoactivity order in the gas phase for the photoreduction of CO₂ to CH₄ mainly depends on the CO₂ molecule adsorption properties on the different exposed facets, and the separation efficiency of the photo-generated carriers determines the photoactivity order for the dye degradation reaction in the liquid phase. These findings also provide a new direction to design efficient photocatalysts and the tuning of their photoreactivity for environmental and energy applications.