Electrocatalytic Acetylene Hydrogenation in Concentrated Seawater at Industrial Current Densities.

Electrocatalytic acetylene hydrogenation to ethylene (E-AHE) is a promising alternative for thermal-catalytic process, yet it suffers from low current densities and efficiency. Here, we achieved a 71.2% Faradaic efficiency (FE) of E-AHE at a large partial current density of 1.0 A cm-2 using concentrated seawater as an electrolyte, which can be recycled from the brine waste (0.96 M NaCl) of alkaline seawater electrolysis (ASE). Mechanistic studies unveiled that cation of concentrated seawater dynamically prompted unsaturated interfacial water dissociation to provide protons for enhanced E-AHE. As a result, compared with freshwater, a twofold increase of FE of E-AHE was achieved on concentrated seawater-based electrolysis. We also demonstrated an integrated system of ASE and E-AHE for hydrogen and ethylene production, in which the obtained brine output from ASE was directly fed into E-AHE process without any further treatment for continuously cyclic operations. This innovative system delivered outstanding FE and selectivity of ethylene surpassed 97.0% and 97.5% respectively across wide-industrial current density range (≤ 0.6 A cm-2). This work provides a significant advance of electrocatalytic ethylene production coupling with brine refining of seawater electrolysis.

On-Substrate Fabrication of CsPbBr3 Single-Crystal Microstructures via Nanoparticle Self-Assembly-Assisted Low-Temperature Sintering.

The growth of all-inorganic perovskite single-crystal microstructures on substrates is a promising approach for constructing photonic and electronic microdevices. However, current preparation methods typically involve direct control of ions or atoms, which often depends on specific lattice-matched substrates for epitaxial growth and other stringent conditions that limit the mild preparation and flexibility of device integration. Herein, we present the on-substrate fabrication of CsPbBr3 single-crystal microstructures obtained via a nanoparticle self-assembly assisted low-temperature sintering (NSALS) method. Sintering guided by self-assembled atomically oriented superlattice embryos facilitated the formation of single-crystal microstructures under mild conditions without substrate dependence. The as-prepared on-substrate microstructures exhibited a consistent out-of-plane orientation with a carrier lifetime of up to 82.7 ns. Photodetectors fabricated by using these microstructures exhibited an excellent photoresponse of 9.15 A/W, and the dynamic optical response had a relative standard deviation as low as 0.1831%. The discrete photosensor microarray chip with 174000 pixels in a 100 mm2 area showed a response difference of less than 6%. This method of nanoscale particle-controlled single crystal growth on a substrate offers a perspective for mild-condition preparation and in situ repair of crystals of various types. This advancement can propel the flexible integration and widespread application of perovskite devices.

Fabrication of stable high-performance urchin-like CeO2/ZnO@Au hierarchical heterojunction photocatalyst for water remediation.

In this paper, the urchin-like CeO2/ZnO@Au photocatalyst was rationally designed and prepared through hydrothermal method, chemical precipitation and photo reduction deposition. The optimal photocatalyst (CZA8) degraded Rhodamine B (RhB), 4-nitrophenol (4-NP) and Naproxen (NPX) about 100% within 20 min, 91.4% within 60 min and 88.9% within 30 min under Xe lamp illumination, respectively. Besides, the CZA8 possesses outstanding photo corrosion resistance capacity which has been verified with the cycle degradation experiments. The photocatalyst displays excellent light response and efficient separation of photo-induced carriers due to the fabrication of type-II heterojunction, the presence of surface plasmon resonance (SPR) effect and as well as the oxygen vacancy. The oxygen vacancy was systematically characterized by XPS, PL and Raman. Moreover, the photocatalytic degradation pathways are proposed based on the LC-MS results. Finally, a novel photocatalytic mechanism for photocatalytic oxidation of RhB, 4-NP and NPX is discussed and schematically illuminated.

Hierarchical Structures Advance Thermoelectric Properties of Porous n-type ß-Ag2Se.

Owing to the intrinsically good near-room-temperature thermoelectric performance, ß-Ag2Se has been considered as a promising alternative to n-type Bi2Te3 thermoelectric materials. Herein, we develop an energy- and time-efficient wet mechanical alloying and spark plasma sintering method to prepare porous ß-Ag2Se with hierarchical structures including high-density pores, a metastable phase, nanosized grains, semi-coherent grain boundaries, high-density dislocations, and localized strains, leading to an ultralow lattice thermal conductivity of ∼0.35 W m-1 K-1 at 300 K. A relatively high carrier mobility is obtained by adjusting the sintering temperature to obtain pores with an average size of ∼260 nm, therefore resulting in a figure of merit, zT, of ∼0.7 at 300 K and ∼0.9 at 390 K. The single parabolic band model predicts that zT of such porous ß-Ag2Se can reach ∼1.1 at 300 K if the carrier concentration can be tuned to ∼1 × 1018 cm-3, suggesting that ß-Ag2Se can be a competitive candidate for room-temperature thermoelectric applications.

Nanostructured monoclinic Cu2Se as a near-room-temperature thermoelectric material.

Searching for new-type, eco-friendly, and Earth-abundant thermoelectric materials, which can be used as an alternative to the high-cost bismuth telluride, is important for near-room-temperature applications. In this work, nanostructured monoclinic Cu2Se with a low carrier concentration has been synthesized by a wet mechanical alloying process combined with spark plasma sintering. Such a low carrier concentration, which originates from the effectively suppressed Cu deficiencies during the fabrication process, induces a relatively low electrical conductivity and carrier thermal conductivity. Besides, the nanostructured grains combined with point defects and phonon resonance enhance the phonon scattering to induce a low lattice thermal conductivity without sacrificing the electrical transport properties. As a result, our nanostructured monoclinic Cu2Se obtains a figure of merit of 0.72 at 380 K with good thermal stability. This work indicates that nanostructured monoclinic Cu2Se is a promising near-room-temperature thermoelectric material.