High Purity Oxygen Production via BBCN Perovskite Hollow Fiber Membrane Swept by Steam

et al. 2020

ACS Appl. Nano Mater.

Self Cite

Pd-based membranes are used for separation of H 2 from different feed stocks; however, their application is limited in the presence of hydrocarbons due to coke deposition on the membrane surface under operation conditions. Herein, we have developed a triple-layered membrane with a nanoporous Linde type A zeolite on the outer side and an ultrathin (1 μm) Pd membrane on the inner side of the Al 2 O 3 hollow fiber substrate. The membrane was successfully synthesized and tested for hydrogen separation in the presence of lighter hydrocarbons. The presence of uniform nanosize pores in the zeolite layer acts as a barrier for the hydrocarbons to come in contact with the Pd membrane and selectively allows H 2 to permeate through the membrane. The membrane showed enhanced performance in the presence of lighter hydrocarbons (C 3 H 8 and C 3 H 6 ) compared to the only internal coated Pd membrane. The membrane showed excellent stability in the presence of propane and propene at 600 °C for 72 h of operation. The triple-layered membrane was used for propane dehydrogenation reaction using 7.5 wt % Cr/Al 2 O 3 catalyst at 600 °C, and the catalytic activity and stability of the catalytic membrane reactor were evaluated. The results revealed a propane conversion in the membrane reactor ∼15% higher than that in the conventional fixed bed catalytic reactor, which is attributed to the continuous removal of hydrogen from the product mixture during the course of the reaction.

Section: Introductionmentioning

confidence: 99%

Nanoporous Zeolite-A Sheltered Pd-Hollow Fiber Catalytic Membrane Reactor for Propane Dehydrogenation

Pati

Dewangan

et al. 2020

ACS Appl. Nano Mater.

Self Cite

“…In this work, we have successfully prepared ZnO hollow fibers with different microstructures through phase inversion/sintering techniques. Hollow fibers offered a higher surface-to-volume ratio and packing density than disk and large tubes. ,,,,,,− Different hollow fibers have also been developed for gas separation and catalysis. − The reduced wall thickness and the increased finger-like channels within the hollow fibers minimized the resistance during transportation. These advantages of hollow fibers make them interesting for industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Preparation of ZIF-8 Membranes on Porous ZnO Hollow Fibers by a Facile ZnO-Induced Method

Chen

et al. 2020

Ind. Eng. Chem. Res.

In the present study, a simple method for the synthesis of the ZIF-8 membrane has been proposed. This method involves growing the ZIF-8 layer onto the external surface of the ZnO porous hollow support, with inner and outer diameters of 1.55 mm and 2.06 mm, respectively. The ZnO hollow fibers with a thin spongy layer and large numbers of finger-like pores were prepared by a phase inversion/sintering technique. These ZnO hollow fibers have proved to be effective supports for the preparation of highly stable and reproducible ZIF-8 membranes. The ZnO support helps in seeding the ZIF-8 membrane formation and then serves as a connecting bridge to link the support with the membrane. The excellent binding strength between ZIF-8 and the support is responsible for the superior mechanical and thermal stabilities of the ZIF-8 membranes. These membranes exhibited great hydrogen permeation (1.2 × 10–6 mol·m–2·s–1·Pa–1) and attained the ideal separation factors for H2/CO2, H2/N2, and H2/CH4 at 7.0, 4.3, and 3.7, respectively, demonstrating good molecular sieve performance. These ZIF-8 membranes displayed preferential adsorption of CO2 and can be potentially applied in CO2 capture from industrial mixed gases. This method requires neither high smoothness of the support surface nor modification of the support, thus providing a simple and comparable technique for the preparation of tubular ZIF and additional MOF membranes.

“…The charge carrier diffusion length of perovskite materials in present reports is typically between 100 to 1000 nm . Moreover, numerous studies have confirmed the charge carrier diffusion length of perovskites is directly related to its crystal size. − The presence of large amounts of surface defect states will lead to the trapping of carriers and further recombination easily, resulting in transmission loss. , In addition, it has been demonstrated that when the single crystal size reaches the centimeter domain, the carrier diffusion length can increase to 175 μm, much higher than that of perovskite polycrystalline films . Therefore, by enhancing the size of the perovskite crystals, the carrier diffusion length can increase over 100 times, and thus can significantly improve the efficiency of the resulted devices. − Numerous researches have been done to get large-sized crystals, but it is still a great challenge apply such in solar cells. − ,, …”

Section: Introductionmentioning

confidence: 73%

Molten Salt-Assisted Growth of Perovskite Films with Submillimeter-Sized Grains

Hou

Qiao

Yang

et al. 2017

Ind. Eng. Chem. Res.

Single crystalline structures with less grain boundaries and longer carrier diffusion length are essential for high performance perovskite solar cells. In this paper, we report a molten salt-assisted method to gain a perovskite film with submillimeter-sized single crystal domains by using excess ammonium salt for the first time. The resulted crystal size can reach 0.5 mm, and an aspect ratio over 1000. A photovoltaic device based on this film exhibits a champion power conversion efficiency (PCE) of 10.12%. This synthetic strategy enables the formation of submillimeter-sized perovskite films first, which holds promise for the understanding of crystallization in organic−inorganic perovskite and paves the way to enhance the efficiency of perovskite solar cells.