Shan Hu,Yunfei Gao,Lu Ding,Xueli Chen,Weitong Pan,Fuchen Wang
Hydroformylation is an important reaction for aldehyde synthesis and requires ethylene and syngas (CO + H2) with the feedstocks. While these feedstocks are typically synthesized separately, it would be highly desirable to directly convert abundant ethane into ethylene and syngas in a single step. In this work, we loaded B2O3 onto perovskite La0.8Sr0.2FeO3 (LSF) and formed a core–shell structured catalyst, with B2O3 and Sr3B2O6 being the shell and LSF being the core. The shell structure can substantially inhibit deep oxidation of ethane into CO2 and the optimized La0.8Sr0.2FeO3@20B2O3 can achieve 69.2% ethane conversion and 88.8% ethylene + syngas selectivity at 700 °C with good stability, with a ratio of CO/H2 close to 1 : 1. The effects of reaction temperature, space velocity, B2O3 loading, and La/Sr were also investigated. This catalyst marks a promising progress for the direct oxidation of ethane and has good potential for industrial applications.
Due to the low material cost, simple preparation process, and no pollution to the environment, dye-sensitized solar cells (DSSCs) have become one of the important power conversion devices. The counter electrode (CE, also called cathode), an important part of DSSCs, plays a critical role in the photovoltaic performance of DSSCs. Platinum (Pt) with high electrocatalytic activity is the most commonly used CE material in DSSCs, which suffers from the problems of high price and poor stability, highlighting the importance of developing novel low-cost, active, and stable Pt-free CEs. In this work, a series of A-site deficient (La0.8Sr0.2)1–xFeO3-δ (x = 0, 0.02, 0.05, 0.1) perovskite oxides are designed to serve as CEs in DSSCs. Through investigating the influence of the A-site deficiency on the power conversion efficiency (PCE), it is found that the introduction of an appropriate deficiency in perovskite oxides is beneficial for catalytic activity of triiodide (I3–) reduction reaction (IRR) of the CE, thus improving the photovoltaic performance of DSSCs. Consequently, the (La0.8Sr0.2)0.98FeO3−δ/multiwalled carbon nanotubes (MWCNTs) CE-based device exhibits the highest PCE of 8.22%, while the Pt-based device only yields a PCE of 7.21%. The significantly enhanced efficiency of DSSCs is mainly attributed to the synergistic effect between the high oxygen vacancy concentration and the appropriate amount of Fe4+ as well as reduced particle size, which enhances the charge transfer capability and the I3– diffusion capability simultaneously. Furthermore, the decent IRR durability of (La0.8Sr0.2)0.98FeO3−δ/MWCNTs composites confers the corresponding DSSCs an excellent long-term stability. This work provides a facile way to design active and durable Pt-free perovskite oxide-based CEs in DSSCs, which may lay the foundation for the commercialization of DSSC technology.
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