Search

Semi-insulating (SI) β-Ga2O3 provides an ultrahigh resistivity that is stable over a wide temperature range which is required in challenging temperature environments, such as in fire prewarning, atmospheric monitoring, and space exploration. A promising deep-level acceptor of Co, which has a more suitable energy location than is found in conventional acceptors (Fe, Mg, etc.), is introduced into the band structure of β-Ga2O3, which might suppress the deterioration of the SI effect and realize the availability of β-Ga2O3 single crystals with stable resistivity in harsh temperature applications. The Co-doped β-Ga2O3 (Co:β-Ga2O3) single crystal possesses a high transmittance and a low free-electron concentration. A stable temperature-dependent resistivity plateau of Co:β-Ga2O3 (which is maintained at 1011 Ω cm from room temperature (RT) to 300 °C) is found for the first time, and the thermal activation energy is fitted to be 2.1 eV, which is closer to the center of the bandgap than that of Fe and Mg. Hence, the dark currents of photodetectors based on the Co:β-Ga2O3 substrate are effectively suppressed, and the photoresponse performances vary subtly from RT to 260 °C. This work shows the ultrahigh resistivity stability and the excellent SI effect of Co:β-Ga2O3 over a wide temperature range, indicating its application prospects in extreme environments and providing more possibilities for the thermal design of β-Ga2O3 devices. [ABSTRACT FROM AUTHOR]

The selectivity towards a specific C2+ product, such as ethylene (C2H4), is sensitive to the surface structure of copper (Cu) catalysts in carbon dioxide (CO2) electro-reduction. The fundamental understanding of such sensitivity can guide the development of advanced electrocatalysts, although it remains challenging at the atomic level. Here we demonstrated that planar defects, such as stacking faults, could drive the electrocatalysis of CO2-to-C2H4 conversion with higher selectivity and productivity than Cu(100) facets in the intermediate potential region (−0.50 ∼ −0.65 V vs. RHE). The unique right bipyramidal Cu nanocrystals containing a combination of (100) facets and a set of parallel planar defects delivered 67% faradaic efficiency (FE) for C2H4 and a partial current density of 217 mA cm−2 at −0.63 V vs. RHE. In contrast, Cu nanocubes with exclusive (100) facets exhibited only 46% FE for C2H4 and a partial current density of 87 mA cm−2 at an identical potential. Both ex situ CO temperature-programmed desorption and in situ Raman spectroscopy analysis implied that the stronger *CO adsorption on planar defect sites facilitates CO generation kinetics, which contributes to a higher surface coverage of *CO and in turn an enhanced reaction rate of C–C coupling towards C2+ products, especially C2H4. [ABSTRACT FROM AUTHOR]

Here we report that in situ reconstructed Cu two-dimensional (2D) defects in CuO nanowires during CO2RR lead to significantly enhanced activity and selectivity of C2H4 compared to the CuO nanoplatelets. Specifically, the CuO nanowires achieve high faradaic efficiency of 62% for C2H4 and a partial current density of 324 mA cm−2 yet at a low potential of −0.56 V versus a reversible hydrogen electrode. Structural evolution characterization and in situ Raman spectra reveal that the high yield of C2H4 on CuO nanowires is attributed to the in situ reduction of CuO to Cu followed by structural reconstruction to form 2D defects, e.g., stacking faults and twin boundaries, which improve the CO production rate and *CO adsorption strength. This finding may provide a paradigm for the rational design of nanostructured catalysts for efficient CO2 electroreduction to C2H4. [ABSTRACT FROM AUTHOR]

Well crystallized and interconnected SnO2 nanoparticles (＜5 nm) were synthesized via oxidation of exfoliated SnS2 sheets. The SnO2 nanoparticles exhibit a high total faradaic efficiency (FE) of 97% towards electrochemical reduction of CO2 at −0.95 V vs. the reversible hydrogen electrode (RHE). The main product ratio of CO/HCOO− which intrinsically correlates to the surface SnOx/Sn ratio variation varies with the applied potential. Beyond CO and HCOO− products formed via the two-electron transfer pathway, hydrocarbons and oxygenates are produced. The formation of hydrocarbon (CH4) versus oxygenate (C2H5OH) depends on the choice of electrolyte (KOH vs. KHCO3), both of which can reach a maximal faradaic efficiency of 10%. The distinctive grain boundary and exposed corner/step sites in the interconnected SnO2 nanoparticles contribute to the high FE of CO2 reduction and unique selectivity. [ABSTRACT FROM AUTHOR]

The identification of chromatic ink particles with characteristics of good light stability, bright color, narrow distribution and high surface charge density is important. In this paper, the preparation of pigment-based RGB tricolor ink particles viamini-emulsion polymerization is reported. Narrow distributed pigment-based ink particles are obtained with the assistance of sodium dodecyl benzenesulfonate. Their large surface charge quantity is confirmed by zeta potential values in the range of −40–−50 mV. The hues of all the ink particles are consistent with their corresponding pigments after coating with polystyrene, according to the diffuse reflectance spectra measurements. In the artificial accelerated aging test (UV radiation exposure for 56 h), the as-prepared samples present good UV light durability, especially compared with the current dye-based ink particles. Finally, a chromatic electrophoretic display cell consisting of tricolor subunits is successfully fabricated using dispersions of RGB ink particles in a mixed dielectric solvent with white particles as contrast. [ABSTRACT FROM AUTHOR]

Here we report that in situ reconstructed Cu two-dimensional (2D) defects in CuO nanowires during CO 2 RR lead to significantly enhanced activity and selectivity of C 2 H 4 compared to the CuO nanoplatelets. Specifically, the CuO nanowires achieve high faradaic efficiency of 62% for C 2 H 4 and a partial current density of 324 mA cm -2 yet at a low potential of -0.56 V versus a reversible hydrogen electrode. Structural evolution characterization and in situ Raman spectra reveal that the high yield of C 2 H 4 on CuO nanowires is attributed to the in situ reduction of CuO to Cu followed by structural reconstruction to form 2D defects, e.g., stacking faults and twin boundaries, which improve the CO production rate and *CO adsorption strength. This finding may provide a paradigm for the rational design of nanostructured catalysts for efficient CO 2 electroreduction to C 2 H 4 .