Lei Cao,Lin Liu,Kaiyi Luo,Pingping Qian,Haowen Chen,Yixiao Deng,Lei Yang,Xiaoyong Wu,Jun Tang
Skutterudites (SKDs) are promising thermoelectric (TE) materials due to their cost-effectiveness and favorable electrical properties. However, their high thermal conductivity limits thermoelectric conversion efficiency. Herein, Y 2 O 3 nanoparticles (NPs)-decorated n-type Yb 0.3 Co 4 Sb 12 were prepared by spark plasma sintering (SPS). The heterointerfaces created by Y 2 O 3 nanoparticles enhance charge carrier localization through O-Sb hybridization and O-Co bonding, which increases the Seebeck coefficient. Additionally, heterointerfaces scatter phonons, reducing thermal conductivity. Consequently, a figure of merit ( ZT ) value of ∼1.48 at 773 K and an average ZT ave of ∼1.0 (293 ∼ 823 K) were achieved in this work.
Highly transparent cerium-doped yttria ceramics were fabricated via a pressureless sintering method with an addition of 10 at.% La 2 O 3 and 1 at.% ZrO 2 as a binary sintering additive. With an increase in the Ce doping concentration from 0 to 3 at.%, the optical absorption edge of yttria ceramics exhibited a significant red shift from 290 to 380 nm as a result of the 4f–5d transition of Ce 3+ and the charge transfer of Ce 4+ (i.e., Ce 4+ +e – →Ce 3+ ). For a 2-mm thick sample doped with 3 at.% Ce, the total ultraviolet radiation (UV) transmittance (220–400 nm) is only 1.7%, indicating a nearly complete UV absorption. Meanwhile, the specimens possess high in-line transmittance levels in both the visible and the infrared regions (i.e., >70% at 450 nm and ∼80% at 1100 nm). Additionally, the present specimens were confirmed to have good enough mechanical strength levels (∼165 MPa) and thermal conductivity (∼5 W/m·K), which are comparable or even better compared to those of previously reported transparent yttria ceramics. The results of this work indicate that cerium-doped transparent yttria ceramics are promising candidate materials for full-band UV-shielding window applications.
Lijia She,Nan Li,Yi Wu,Xi Xi,Yafei Liu,Peng Shen,Gang Zhao,Jiangquan Ma
Designing efficient and stable oxygen evolution reaction (OER) catalysts is of great significance for hydrogen production technology through the electrolysis of water. Nickel sulfide (NixSy) has garnered considerable attention as an OER electrocatalyst owing to its high electrical conductivity and distinctive structure. Herein, Ni3S4–Yb2O3 on nickel foam electrocatalysts was fabricated through a hydrothermal synthesis approach to optimize the performance of Ni3S4. The incorporation of Yb2O3 induced charge redistribution within Ni3S4, expanded the active surface area, and enhanced the availability of active sites. Consequently, the Ni3S4–Yb2O3/NF catalyst demonstrates exceptional electrocatalytic performance in 1 M KOH, attaining a current density of 10 mA cm–2 at a minimal overpotential of 148 mV, along with an ultralow Tafel slope of 47.3 mV dec–1. In addition, we have confirmed that another reason for the improved performance is that Yb2O3, as an electron donor, can effectively regulate the defects of the Ni atoms. This work offers a feasible strategy for developing highly effective OER electrocatalysts in alkaline media.
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