Constructing a semiconductor type II structure is an effective way to enhance the photogenerated charge separation efficiency. The separation and migration of interfacial photogenerated carriers is a key factor, which influences the photocatalytic activity. In this study, a conformal Al2O3 recombination barrier layer was introduced at the interface between TiO2 nanowires and CdSe nanoparticles, and the application of this composite in photoelectrocatalytic (PEC) hydrogen production was explored. Under visible-light irradiation, the photocurrent response and PEC hydrogen evolution performance increased step-by-step from TiO2 to the Al2O3/TiO2 and CdSe/Al2O3/TiO2 nanowire arrays. Moreover, the H2 evolution rate of CdSe/Al2O3/TiO2 was much higher than that of a different configuration, Al2O3/CdSe/TiO2. The enhanced PEC hydrogen evolution performance was attributed to the prevention of the interfacial charge recombination caused by the Al2O3 recombination barrier layer. Our results may shed new light on developing novel and highly efficient photocatalysts using rational interface design.

Developing visible light-driven photocatalyst has been paid a lot of attentions due to the intention of utilizing the solar energy. In this present work, novel visible light-driven S-doped carbon dots (S-CDs)/BiOI composites were synthesized via a facile hydrothermal method and followed by a chemisorption. The S-doped carbon dots were applied in the photocatalytic reaction for the first time and show promising results. The S-CDs/BiOI composite was formed with S-CDs uniformly deposited on the surface of thin BiOI nanosheet. All S-CDs/BiOI composites exhibit higher photocatalytic degradation activities of methylene blue (MB) than pure BiOI, and the optimal modification proportion of S-CDs is 1%. And the S-CDs/BiOI composite also exhibits much higher photocatalytic activities than undoped CDs/BiOI composite. The improved photocatalytic performance of S-CDs/BiOI is attributed to the interfacial transfer of electrons from BiOI to S-CDs, resulting in a more effective charge separation and enhanced photocatalytic activity. For the photocatalytic degradation of MB, the active species trapping experiments indicate that the superoxide radical is the main active species of the S-CDs/BiOI composite. Our results suggest that sulfur doping can further improve the performance of CDs and CDs modification can effectively enhance the photocatalytic activity.

Nanosheet ZSM-5 zeolite with highly exposed (010) crystal planes demonstrates high reactivity and good anti-coking stability for the catalytic cracking of n-heptane, which is attributed to the synergy of high external surface area and acid sites, fully accessible channel intersection acid sites, and hierarchical porosity caused by the unique morphology.

The control of the photocatalytic activity of TiO2 by tailoring their crystalline structure and electronic structure is a current topic of great interest. In the present study, the phase composition and exposed facets on Ti3+ self-doped TiO2 were regulated by simply changing the fluorinion concentration during the hydrothermal synthesis process of TiO2. It was found that the phase composition can be tuned facilely, and the phase transformation process was analyzed by XRD and UV Raman spectroscopy. The introducing fluorinion during the hydrothermal preparation of TiO2 resulted in F-doping and phase transformation. And the F-doping also affects the amount of Ti3+ ions in the TiO2. SEM analysis indicated that the morphology and exposed facets changed with the change in fluorinion concentration, and the ratios of exposed facets are adjustable. Through systematically optimizing these parameters, the TiO2 prepared under fluorinion concentration of 17.5 mM showed the excellent photocatalytic performance under full spectrum illumination. The good photocatalytic performance was mainly attributed to the more phase junctions and surface heterojunctions for enhancing charge separation.

A CdS encapsulated carbon nanotube (CNT) photocatalyst was prepared by a liquid-chemistry method. Through filling of CNTs with CdS, the aggregation of CdS was prevented efficiently by the good confinement effect of CNTs, and the photocatalytic performance of CdS was enhanced by 2.5 times via synergistic integration of the confinement effect of CNTs and heterojunction between CNTs and CdS. The photostability of CdS encapsulated in and attached on CNTs was investigated systematically through methylene blue photocatalytic degradation, X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy. The results indicate that the photocorrosion of CdS is successfully suppressed when it is encapsulated in the CNTs. The mechanism analysis suggests that spatial synergy of the CdS and powerful adsorptivity of CNTs are the primary causes for photocorrosion inhibition. Our efforts propose a new scheme to remarkably promote both the photostability and photocatalytic activity of photocorrosion-susceptible photocatalysts.

A photonic crystal-based CdS–Au–WO3 heterostructure was constructed on WO3 photonic crystal segments. Highly efficient visible-light-driven hydrogen and oxygen evolution are demonstrated relative to those of single-, two-component and unstructured systems due to good light harvesting of photonic crystals and efficient electron transfer of this heterostructure.

•TiO2/CdS was structured into hollow sphere with Pt loaded onto the internal wall.•Vectorial electron transfer and spatially separated reaction surfaces were achieved.•The as-prepared catalyst exhibits good photocatalytic hydrogen evolution activity.•The underlying mechanism for the photocatalytic hydrogen evolution was proposed.Solar driven semiconductor photocatalytic water splitting to produce hydrogen is an extremely charming process by storing photon energy in chemical bonds. In the present study, composite semiconductor TiO2/CdS was structured into uniform and porous double-shelled hollow sphere with cocatalyst platinum selectively loaded onto the internal wall. The SEM, TEM, STEM, XRD, BET and EDS elemental distribution etc. were employed to evidence the formation of the targeted photocatalyst. It was demonstrated that the material has a high efficiency of visible-light-driven hydrogen evolution (296 μmol·h−1/10 mg) with an apparent quantum efficiency (QE) of 14.5% at wavelength of 420 nm. Comparative experiment analysis and time-resolved infrared absorption study suggested that the high photocatalytic activity of the catalyst is attributed to the vectorial electron transfer (CdS → TiO2 → Pt) and the spatial separation of reduction and oxidation active surfaces achieved by the special morphology.Porous hollow sphere of h-(Pt–TiO2)/CdS, with outer shell of CdS as an antenna for visible light, and internal shell of TiO2 with Pt nanoparticles as H2 evolution active layer, exhibits a high efficiency of visible-light-driven photocatalytic H2 production. The excellent catalytic performances are attributed to the synergetic effects of the ideal electron transfer and the spatial separation of reduction and oxidation active surfaces.

A novel two-dimensional (2D) Mn(II) coordination polymer [Mn1.5(H2bdc)1.5(DMA)2] (1; H2bdc = terephthalic acid; DMA = N,N′-dimethylacetamide) based on trinuclear manganese subunit has been solvothermally prepared and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits a rare layered structure with 6-connected hxl topology constructed from the trinuclear Mn3(COO)6 units, and further stacking of layers leads to a 3D supramolecular framework. The thermalgravimetric behavior and magnetic property of 1 have been also investigated. The magnetic susceptibility measurements reveal that the compound exhibits antiferromagnetic coupling interactions.Presented here is a novel two-dimensional (2D) Mn(II) coordination polymer constructed from trinuclear manganese subunits, which exhibits a rare layered structure with hxl topology and antiferromagnetic property.Highlights► A novel two-dimensional (2D) Mn(II) coordination polymer constructed from trinuclear manganese subunits. ► A rare layered structure with 6-connected hxl topology. ► Antiferromagnetic coupling interactions between Mn centers in the trinuclear Mn unit.

A series of fluorinated HZSM-5 zeolites (F/HZSM-5) were prepared by immersing the zeolites with different concentrations of NH4F solution, and their performances for the catalytic cracking of naphtha to produce light olefins were investigated. The results indicated that F-modified HZSM-5 zeolites are effective catalysts for the cracking of naphtha to light olefins. At the temperature of 600 °C, the yields of propene and ethene were achieved at 36.4 and 20.2%, which were 7.3 and 4.3% higher than those over parent HZSM-5 zeolite, respectively. The physicochemical features of F/HZSM-5 catalysts were characterized by means of X-ray diffraction (XRD), Brunauer−Emmett−Teller (BET), temperature-programmed desorption of ammonia (NH3-TPD), Fourier transform infrared (FTIR) spectra of adsorbed pyridine, etc. The results indicated that fluorine (F) modification not only regulates the pore characteristics of the HZSM-5 zeolites but also modulates the amount of acid sites, especially the amount of Brönsted (B) acid. Consequently, F modification with suitable content was favorable for increasing the conversion of naphtha and enhancing the selectivity to light olefins.

A series of HZSM-5 zeolites modified by different amounts of phosphorus (P/HZSM-5) were prepared, and their catalytic performances for the coupling reaction of methanol and C4 hydrocarbons to light olefins were investigated. The results indicated that P/HZSM-5 is a highly efficient catalyst for the transformation of methanol and 1-butene to propene with low-energy consumption. At the temperature of 550 °C, the maximum yield of propene was achieved at 44.0%, which was 7.4 and 4.5% higher than those on 1-butene catalytic cracking and methanol to olefins (MTO), respectively. X-ray photoelectron spectroscopy (XPS) characterization on the catalyst showed that P bonds to the HZSM-5 zeolite framework through oxygen. The enhanced coupling performances can be correlated to the combined effects of matching of the co-feedings and the suitability of the P/HZSM-5 catalyst.

•A highly efficient Au@CdS/MIL-101 heterostructure was synthesized.•The Au@CdS/MIL-101 heterostructure presents a higher H2 evolution rate.•The H2 evolution rate of Au@CdS/MIL-101 is 2.6 times higher than that of pure CdS.•The enhanced performance is ascribed to MIL-101 and surface plasmon resonance of Au.A novel and highly efficient three-component Au@CdS/MIL-101 heterostructure was successfully synthesized. The MIL-101(Cr) with large surface area was introduced as a matrix for the well-dispersed growth of Au nanoparticles, and the CdS was selectively coated on the Au nanoparticles. Under visible light irradiation, the Au@CdS/MIL-101 heterostructure presents superior hydrogen evolution rate over the pure CdS, CdS/MIL-101 and Au/MIL-101 composites. The Au@CdS/MIL-101 heterostructure exhibits an unusual H2 production rate of 250 μmol h−1/10 mg, which is 2.6 times higher than that of pure CdS. The performance enhancement of Au@CdS/MIL-101 heterostructure can be attributed to the following reasons: (i) the large surface area of MIL-101(Cr) can effectively disperse the Au and CdS nanoparticles, resulting in more active adsorption sites and reaction centers. (ii) the strong surface plasmon resonance absorption of Au could accelerate the charge transfer and extend the light response spectrum of CdS. This three-component Au@CdS/MIL-101 heterostructure combining the large surface area of MOF and the surface plasmon resonance of Au into a single structure may provide a potential way to design highly efficient and solar-energy-harvesting photocatalysts.

Nanosheet ZSM-5 zeolite with highly exposed (010) crystal planes demonstrates high reactivity and good anti-coking stability for the catalytic cracking of n-heptane, which is attributed to the synergy of high external surface area and acid sites, fully accessible channel intersection acid sites, and hierarchical porosity caused by the unique morphology.

A CdS encapsulated carbon nanotube (CNT) photocatalyst was prepared by a liquid-chemistry method. Through filling of CNTs with CdS, the aggregation of CdS was prevented efficiently by the good confinement effect of CNTs, and the photocatalytic performance of CdS was enhanced by 2.5 times via synergistic integration of the confinement effect of CNTs and heterojunction between CNTs and CdS. The photostability of CdS encapsulated in and attached on CNTs was investigated systematically through methylene blue photocatalytic degradation, X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-atomic emission spectroscopy. The results indicate that the photocorrosion of CdS is successfully suppressed when it is encapsulated in the CNTs. The mechanism analysis suggests that spatial synergy of the CdS and powerful adsorptivity of CNTs are the primary causes for photocorrosion inhibition. Our efforts propose a new scheme to remarkably promote both the photostability and photocatalytic activity of photocorrosion-susceptible photocatalysts.