Noble-Metal-Free Ni-W-O-Derived Catalysts for High-Capacity Hydrogen Production from Hydrazine Monohydrate

Preparation and Photocatalytic Performance of MoS2/MoO2 Composite Catalyst

Solar energy is an inexhaustible clean energy providing a key solution to the dual challenges of energy and environmental crises. Graphite-like layered molybdenum disulfide (MoS₂) is a promising photocatalytic material with three different crystal structures, 1T, 2H and 3R, each with distinct photoelectric properties. In this paper, 1T-MoS₂ and 2H-MoS₂, which are widely used in photocatalytic hydrogen evolution, were combined with MoO₂ to form composite catalysts using a bottom-up one-step hydrothermal method. The microstructure and morphology of the composite catalysts were studied by XRD, SEM, BET, XPS and EIS. The prepared catalysts were used in the photocatalytic hydrogen evolution of formic acid. The results show that MoS₂/MoO₂ composite catalysts have an excellent catalytic effect on hydrogen evolution from formic acid. By analyzing the photocatalytic hydrogen production performance of composite catalysts, it suggests that the properties of MoS₂ composite catalysts with different polymorphs are distinct, and different content of MoO₂ also bring differences. Among the composite catalysts, 2H-MoS₂/MoO₂ composite catalysts with 48% MoO₂ content show the best performance. The hydrogen yield is 960 µmol/h, which is 1.2 times pure 2H-MoS₂ and two times pure MoO₂. The hydrogen selectivity reaches 75%, which is 22% times higher than that of pure 2H-MoS₂ and 30% higher than that of MoO₂. The excellent performance of the 2H-MoS₂/MoO₂ composite catalyst is mainly due to the formation of the heterogeneous structure between MoS₂ and MoO₂, which improves the migration of photogenerated carriers and reduces the possibilities of recombination through the internal electric field. MoS₂/MoO₂ composite catalyst provides a cheap and efficient solution for photocatalytic hydrogen production from formic acid.

Potential-Mediated Recycling of Copper From Brackish Water by an Electrochemical Copper Pump

Copper ions (Cu2+ ) disposed to the environment at massive scale pose severe threat to human health and waste of resource. Electrochemical deionization (EDI) which captures ions by electrical field is a promising technique for water purification. However, the removal capacity and selectivity toward Cu2+ are unsatisfying, yet the recycling of the captured copper in EDI systems is yet to be explored. Herein, an efficient electrochemical copper pump (ECP) that can deliver Cu2+ from dilute brackish water into much more concentrated solutions is constructed using carbon nanosheets for the first time, which works based on reversible electrosorption and electrodeposition. The trade-off between the removal capacity and reversibility is mediated by the operation voltage. The ECP exhibits a removal capacity of 702.5 mg g-1 toward Cu2+ and a high selectivity coefficient of 64 for Cu2+ /Na+ in the presence of multiple cations; both are the highest reported to date. The energy consumption of 1.79 Wh g-1 is among the lowest for EDI of copper. More importantly, the Cu species captured can be released into a 20-fold higher concentrated solution. Such a high performance is attributed to the optimal potential distribution between the two electrodes that allows reversible electrodeposition and efficient electrosorption.

Design of a ratiometric near-infrared fluorescent probe with double excitation for hydrazine detection in vitro and in vivo

Hydrazine has a wide range of industrial applications, but it is also a toxic and explosive chemical substance, which brings potential risks to human health and environmental safety. Therefore, rapid and sensitive monitoring of hydrazine is of great importance in environmental sciences and biological systems. In this work, a new near-infrared (NIR) ratiometric fluorescent probe (Ac-HY) was designed to detect hydrazine under double excitation and emission mode. Ac-HY exhibited large stokes shift (130 nm), high selectivity and sensitivity to hydrazine detection. The applications of Ac-HY probe for detecting hydrazine in vapor and imaging hydrazine in lipid droplets and zebrafish. Therefore, Ac-HY can be used to monitor the distribution of exogenous hydrazine in vitro and in vivo.

Free-standing Pt-Ni nanowires catalyst for H2 generation from hydrous hydrazine

Free-standing Pt-Ni nanowires were fabricated by a one-pot solvothermal method. Nanowires with an optimal Pt/Ni ratio of 1.86 exhibited a high activity and a 100% H2 selectivity for hydrous hydrazine decomposition at mild temperatures, which are comparable to the levels of supported catalysts. Our study reveals for the first time that basic support is not a prerequisite for achieving favorable catalytic performance and provides a renewed perspective for the design of advanced catalysts for on-demand H2 generation from hydrous hydrazine.

Noble-metal-free nanocatalysts for hydrogen generation from boron- and nitrogen-based hydrides

We focus on the recent advances in non-noble metal catalyst design, synthesis and applications in dehydrogenation of chemical hydrides (e.g. NaBH₄, NH₃BH₃, NH₃, N₂H₄, N₂H₄BH₃) due to their high hydrogen contents and CO-free H₂ production.