Clarifying the Direct Generation of OH Radicals in Photocatalytic O Reduction: Theoretical Prediction Combined with Experimental Validation.

This work systematically studied thermocatalytic and photocatalytic pathways of formaldehyde degradation and H-assisted O reduction over a Pt/anatase-TiO(101) composite via DFT calculations together with constrained molecular dynamics (MD) simulations. We show that photocatalytic O reduction on Pt/TiO can directly generate OH radicals (*O → *OOH → OH) via two hydrogenation steps with small barriers, and the product selectivity (*HO or OH) is decided by the relative position between catalyst Fermi level and OH/*HO redox potential (theoretical determination of 0.07 V referencing to the SHE).

Construction of Ultrafine PtIr Clusters Supported on CoO Nanoflowers for Enhanced Overall Water Splitting.

Green hydrogen production through electrochemical overall water splitting has suffered from sluggish oxygen evolution reaction (OER) kinetics, inferior conversion efficiency, and high cost. Herein, ultrafine PtIr clusters are synthesized via an electrodeposition method and decorated on the CoO nanoflowers assembled by nanowires (PtIr-CoO). The encouraging performances in electrochemical OER and hydrogen evolution reaction (HER) are achieved over the PtIr-CoO catalyst, with the overpotentials as low as 410 and 237 mV at 100 mA cm, respectively, outperforming the commercial IrO and Pt/C catalysts.

Generalized Rapid Synthesis of Supported Nanocluster Catalyst for Mild Hydrogenation of Phenol toward KA Oil.

Homogeneous and nanometric metal clusters with unique electronic structures are promising for catalysis, however, common synthesis techniques for metal clusters suffer from large size and even metal nanocrystals attributing to their high surface energy and unsaturated configurations. Herein, a generalized rapid annealing strategy for synthesizing a series of supported metal clusters as superior catalysts is developed. Remarkably, TiO supported platinum nanoclusters (Pt NC/TiO ) exhibits the excellent catalytic activity to realize phenol hydrogenation under mild conditions.

Strategies to Improve the Oxygen Reduction Reaction Activity on Pt-Bi Bimetallic Catalysts: A Density Functional Theory Study.

Decreasing the level of use of Pt in proton exchange membrane fuel cells is of great research interest both academically and industrially. In this work, we systematically studied the oxygen reduction reaction (ORR) following the four-electron association mechanism at various Pt-Bi surfaces with density functional theory calculations. The results showed that the introduction of Bi changes the potential-determining step of ORR.

Hierarchical Ni-Mo-P nanoarrays toward efficient urea oxidation reaction.

The urea oxidation reaction (UOR), which possesses a low theoretical potential and superior kinetics, is an attractive substitute for the anodic oxygen evolution reaction (OER) in overall water splitting; however, the implementation of hydrogen production in overall urea splitting is impeded by the deficiency of highly efficient, durable and cost-effective catalysts. Herein, we fabricated an NiP-MoP heterostructure with a hierarchical structure grown on carbon paper (Ni-Mo-P/CP), which exhibited robust activity and outstanding durability for the electrocatalytic oxidation of urea. The Ni-Mo-P/CP catalyst possessed an ultralow potential of 1.

An amorphous ultrathin iridium/carbon catalyst realizing efficient electrochemical hydrogen evolution.

An amorphous 1.1 nm Ir/C catalyst exhibits ultralow overpotentials of 10 and 64 mV for the hydrogen evolution reaction at current densities of 10 and 100 mA cm, together with 117 A mg mass activity and outstanding long-term durability, superior to those of the commercial Pt/C catalyst.

Ice as Solid Electrolyte To Conduct Various Kinds of Ions.

Water, considered as a universal solvent to dissolve salts, has been extensively studied as liquid electrolyte in electrochemical devices. The water/ice phase transition at around 0 °C presents a common phenomenon in nature, however, the chemical and electrochemical behaviors of ice have rarely been studied. Herein, we discovered that the ice phase provides efficient ionic transport channels and therefore can be applied as generalized solid-state ionic conductor.

Room temperature Mg reduction of TiO: formation mechanism and application in photocatalysis.

Defects in metal oxides can significantly improve their physical and chemical properties. However, the conventional methods to generate defects often require complex procedures and harsh conditions. In this study, we design a simple and room-temperature preparation route to prepare defective metal oxide nanoparticles with high yield.

Ultralow-temperature photochemical synthesis of atomically dispersed Pt catalysts for the hydrogen evolution reaction.

Efficient control of nucleation is a prerequisite for the solution-phase synthesis of nanocrystals. Although the thermodynamics and kinetics of the formation of metal nanoparticles have been largely investigated, fully suppressing the nucleation in solution synthesis remains a major challenge due to the high surface free energy of isolated atoms. In this article, we largely decreased the reaction temperature for ultraviolet (UV) photochemical reduction of HPtCl solution to -60 °C and demonstrated such a method as a fast and convenient process for the synthesis of atomically dispersed Pt.

Large Piezoelectric Strain in Sub-10 Nanometer Two-Dimensional Polyvinylidene Fluoride Nanoflakes.

Functional polymers such as polyvinylidene fluoride (PVDF) and its copolymers, which exhibit room-temperature piezoelectricity and ferroelectricity in two-dimensional (2D) limit, are promising candidates to substitute hazardous lead-based piezoceramics for flexible nanoelectronic and electromechanical energy-harvesting applications. However, realization of many polymers including PVDF in ultrathin 2D nanostructures with desired crystal phases and tunable properties remains challenging due to ineffective conventional synthesis methods. Consequently, it has remained elusive to obtain optimized piezoelectric performance of PVDF particularly in sub-10 nm regimes.

-60 °C solution synthesis of atomically dispersed cobalt electrocatalyst with superior performance.

Temperature can govern morphologies, structures and properties of products from synthesis in solution. A reaction in solution at low temperature may result in different materials than at higher temperature due to thermodynamics and kinetics of nuclei formation. Here, we report a low-temperature solution synthesis of atomically dispersed cobalt in a catalyst with superior performance.

Boosting the Electrocatalytic Water Oxidation Performance of CoFeO Nanoparticles by Surface Defect Engineering.

Spinel oxides have attracted widespread interest for electrocatalytic applications owing to their unique crystal structure and properties. The surface structure of spinel oxides significantly influences the electrocatalytic performance of spinel oxides. Herein, we report a Li reduction strategy that can quickly tune the surface structure of CoFeO (CFO) nanoparticles and optimize its electrocatalytic oxygen evolution reaction (OER) performance.

Ice Melting to Release Reactants in Solution Syntheses.

Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO was frozen and dropped into a reductive NaBH solution at about 0 °C.

Ultra-low-temperature growth of CdS quantum dots on g-CN nanosheets and their photocatalytic performance.

CdS quantum dots deposited on carbon nitride (g-CN) nanosheets have been synthesized by ultra-low temperature (-60 °C) liquid phase precipitation reactions. The obtained CdS quantum dots were uniformly distributed on the surface of the g-CN nanosheets with an average diameter of 5 nm. Correspondingly, CdS/g-CN exhibits a highly enhanced photocatalytic performance.

Iced photochemical reduction to synthesize atomically dispersed metals by suppressing nanocrystal growth.

Photochemical solution-phase reactions have been widely applied for the syntheses of nanocrystals. In particular, tuning of the nucleation and growth of solids has been a major area of focus. Here we demonstrate a facile approach to generate atomically dispersed platinum via photochemical reduction of frozen chloroplatinic acid solution using ultraviolet light.

Enhanced Electrocatalytic Activity for Water Splitting on NiO/Ni/Carbon Fiber Paper.

Large-scale growth of low-cost, efficient, and durable non-noble metal-based electrocatalysts for water splitting is crucial for future renewable energy systems. Atomic layer deposition (ALD) provides a promising route for depositing uniform thin coatings of electrocatalysts, which are useful in many technologies, including the splitting of water. In this communication, we report the growth of a NiO/Ni catalyst directly on carbon fiber paper by atomic layer deposition and report subsequent reduction and oxidation annealing treatments.

Direct Blow-Spinning of Nanofibers on a Window Screen for Highly Efficient PM Removal.

Particulate matter (PM) pollution has caused many serious public health issues. Whereas indoor air protection usually relies on expensive and energy-consuming filtering devices, direct PM filtration by window screens has attracted increasing attention. Recently, electrospun polymer nanofiber networks have been developed as transparent filters for highly efficient PM removal; however, it remains challenging to uniformly coat the nanofibers on window screens on a large scale and with low cost.