Ce–Mn Oxide Nanocomposites for Catalytic Removal of H₂S

Abstract

The development of efficient and stable nanocatalysts is crucial for the catalytic removal of H 2 S through selective oxidation to sulfur. Inspired by the different catalytic activity and selectivity of CeO 2 and MnO 2 for the reaction, cerium−manganese (Ce−Mn) nanocomposite oxides with tunable phase structure and unique surface properties were constructed to optimize the catalytic performance. By regulating the molar ratio of Ce and Mn components, a novel catalyst structure comprising Ce−Mn solid solution and amorphous CeO 2 is synthesized from Ce−Mn oxide with n Ce /n Mn ratio of 0.5 (50Ce−Mn). Compared with the unmodified MnO 2 , the tailored 50Ce−Mn possesses a high specific surface area, which facilitates the access of reactants to active sites and the desorption of formed sulfur. More importantly, strong Ce−Mn interaction and abundant surface-active oxygen species are generated, contributing to the regeneration of Mn 4+ /Ce 4+ active sites, facilitating the formation of sulfur, and inhibiting the accumulation of sulfates during the reaction. Consequently, 50Ce−Mn presents a superior catalytic activity (T 100 of 150 °C), stability, and sulfur selectivity even under relatively high weight hourly space velocity conditions (23,000 mL•g −1 •h −1 ). This study provides an example of how catalytic performance can be boosted through phase structure regulation on nanocomposites.

Polystyrene/Polymethylhydrosiloxane Multiscale Electrospun Nanofiber Membranes for Air Filtration

“…Therefore, we conducted filtration tests on the fiber membranes using solid NaCl and oily Dop (PM 0.3 ) particles. 24,34 As shown in Figure 4a, the filtration efficiency for NaCl particles was 95.69% at a wind speed of 32 L/min for the PS−PHMS-5% membrane, which increased to 99.98% for the PS−PHMS-20% membrane. Simultaneously, the pressure drop increased from 49.8 to 85 Pa because the smaller fiber diameter and pore size in PS−PHMS-20% enhanced the capability to intercept particles.…”

“…19−21 In the early stages of this study, we used electrospinning technology to prepare a multiscale nanofiber composite web with a layer ratio of conventional fibers (200 nm) to ultrafine fibers (28 nm) of 1:1, 22 which was applied in window-screen filtration and achieved a filtration efficiency of 99.91%. We also prepared a layer of ultrafine fibers (20−35 nm) on an N-halaminemodified PVDF scaffold, 23 which achieved a removal efficiency of 99.93% for PM 0.3 and a filtration resistance of 79 Pa. Zhang 24 et al prepared a PAN/PAN-FPU composite membrane (thickness ratio = 1:3) with a filtration efficiency of 99.84% and filtration resistance of 163 Pa.…”

Highly Dispersed FeAg-MCM41 Catalyst for Medium-Temperature Hydrogen Sulfide Oxidation in Coke Oven Gas

“…However, after adding Fe and Ag, strong signals appear at g = 2.003, accounting for unpaired electrons in oxygen vacancies found in Fe/Ag-doped catalysts. 39 The signal intensity is decreased in the order 30Fe5Ag-MCM41 > 5Ag-MCM41 > 30Fe-MCM41 > MCM41, indicating that the addition of both Fe and Ag contributes to the formation of oxygen vacancies. According to the literature, these oxygen vacancies might result from the formation of Fe(II) and Ag 0 in the XPS analysis.…”

“…No signal is observed in the MCM41 sample. However, after adding Fe and Ag, strong signals appear at g = 2.003, accounting for unpaired electrons in oxygen vacancies found in Fe/Ag-doped catalysts . The signal intensity is decreased in the order 30Fe5Ag-MCM41 > 5Ag-MCM41 > 30Fe-MCM41 > MCM41, indicating that the addition of both Fe and Ag contributes to the formation of oxygen vacancies.…”

Robust and Sustainable Indium Anode Leading to Efficient and Stable Organic Solar Cells

“…In addition, beyond the small‐area OSCs, the feasibility to access large area modules [ 54–56 ] was demonstrated. Through an aqueous soaking process, we have succeeded in preparing large‐area InCl 3 –ITO substrates with excellent uniformity and optoelectronic properties, which impressively led to high‐performance organic solar modules ( Figure ; Supporting Information).…”