The roles and mechanism of cocatalysts in photocatalytic water splitting to produce hydrogen

Photocatalytic hydrogen(H2)evolution via water spilling over semiconductors has been considered to be one of the most promising strategies for sustainable energy supply in the future to provide non-pollution and renewable energy.The key to efficient conversion of solar-chemical energy is the design of an efficient structure for high charge separation and transportation.Therefore,cocatalysts are necessary in boosting photocatalytic H2 evolution.To date,semiconductor photocatalysts have been modified by various cocatalysts due to the extended light harvest,enhanced charge carrier separation efficiency and improved stability.This review focuses on recent developments of cocatalysts in photocatalytic H2 evolution,the roles and mechanism of the cocatalysts are discussed in detail.The cocatalysts can be divided into the following categories:metal/alloy cocatalysts,metal phosphides cocatalysts,metal oxide/hydroxide cocatalysts,carbon-based cocatalysts,dual cocatalysts,Z-scheme cocatalysts and MOFs cocatalysts.The future research and forecast for photocatalytic hydrogen generation are also suggested.

Brain cell apoptosis and enhancement of nervous excitability in pregnant rats with high plasma levels of homocysteine

Hyperhomocysteinemia is an important risk factor for preeclampsia-eclampsia. This study established a pregnant rat model of hyperhomocysteinemia, in which blood plasma homocysteine concentrations were twice or three times greater than that of normal pregnant rats. TUNEL revealed an increase in the number of apoptotic cells in the frontal cortex of pregnant rats with hyperhomocysteinemia. In addition, immunohistochemical staining detected activated nuclear factor-KB-positve cells in the frontal cortex. Reverse transcription-PCR detected that mRNA expression of the anti-apoptotic gene bcl-2 diminished in the frontal cortex. In situ hybridization and western blotting revealed that N-methyi-D- aspartate receptor 1 mRNA and protein expression was upregulated in the frontal cortex and hippocampus. These results indicate that hyperhomocysteinemia can induce brain cell apoptosis, increase nerve excitability, and promote the occurrence of preeclampsia in pregnant rats.

Design and applications of hollow‐structured nanomaterials for photocatalytic H2 evolution and CO2 reduction

Photocatalysis is considered a prospective way to alleviate the energy crisis and environmental pollution.It is therefore extremely important to design highly efficient photocatalysts for catalytic systems.In recent years,hollow‐structured materials have attracted considerable interest for application in energy conversion fields owing to their large specific surface areas,improved light absorption,and shortened charge carrier transfer path.Because they contain inner and outer surfaces,hollow‐structured materials can provide a superior platform for the deposition of other components.A number of hollow‐structured hierarchical systems have been designed and fabricated in recent decades.It is important to rationally design and construct complex hierarchical structures.In this review,general preparation approaches for hollow‐structured materials are presented,followed by a summary of the recent synthesis methods and mechanisms of typical hollow‐structured materials for applications in the photocatalytic field.Complex hollow‐structured hierarchical photocatalysts are classified into two types,hollow cocatalyst‐based and hollow host photocatalyst‐based,and the design principle and analysis of the photocatalytic reaction mechanism for photocatalytic H2 evolution and CO_(2) reduction are also introduced.The effects of hollow‐structured materials have also been investigated.This review provides a reference for the rational construction of advanced,highly efficient photocatalytic materials.

Synthesis of ternary Ni_(2)P@UiO‐66‐NH_(2)/Zn_(0.5)Cd_(0.5)S composite materials with significantly improved photocatalytic H_(2)production performance

The design and construction of low‐cost and high‐performance hybrid materials for the photocatalytic hydrogen production reaction(HER)are extremely important for the large‐scale application of hydrogen energy.Metal‐organic frameworks(MOFs)are considered to be potential photocatalytic materials.Herein,monodisperse,small size,non‐precious metal transition metal phosphide Ni2P is encapsulated into a typical MOF(UiO‐66‐NH2)as a hybrid core‐shell cocatalyst to modify Zn_(0.5)Cd_(0.5)S for photocatalytic hydrogen production.Ni2P is wrapped in UiO‐66‐NH_(2)via an in situ solvothermal method,and Zn_(0.5)Cd_(0.5)S sulfide is decorated with a core‐shell Ni_(2)P@UiO‐66‐NH_(2)cocatalyst to obtain ternary Ni_(2)P@UiO‐66‐NH_(2)/Zn_(0.5)Cd_(0.5)S composite materials.Photoelectric and chemical characterization confirms that the ternary composites have good kinetic hydrogen production performance.The hydrogen production rate of 10%10 mg Ni_(2)P@UiO‐66‐NH_(2)/Zn_(0.5)Cd_(0.5)S reaches 40.91 mmol·g^(–1)·h^(–1)with an apparent quantum efficiency at 420 nm of 13.57%.The addition of 10 mg Ni_(2)P@UiO‐66‐NH_(2)increases the surface area of the ternary material,providing abundant reaction sites and forming an efficient charge transfer channel,which is conducive to efficient hydrogen production by the ternary photocatalysts.It is shown that the formation of a ternary composite system is beneficial to the occurrence of an efficient catalytic reaction.This study provides a new perspective for the construction of high‐performance photocatalytic materials.

GREY DISPLACEMENT INPUT－OUTPUT MODELS OF MINERAL PROCESSING－METALLURGY SYSTEM

ＧＲＥＹＤＩＳＰＬＡＣＥＭＥＮＴＩＮＰＵＴ－ＯＵＴＰＵＴＭＯＤＥＬＳＯＦＭＩＮＥＲＡＬＰＲＯＣＥＳＳＩＮＧ－ＭＥＴＡＬＬＵＲＧＹＳＹＳＴＥＭＨａｎ；ＸｕｌｉＬｉ；Ｓｏｎｇｒｅｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭｉｎｅｒａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｃｅｎｔｒ...