Self-Supported Nickel Hollow Fiber Membranes: A Catalyst-free Path to Intensified Dry Reforming

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Abstract Dry reforming of methane (DRM) is pivotal for a sustainable CO2 value chain. The current main challenge to realize the large-scale application of DRM lies in the rapid catalyst degradation due to coking and sintering. Herein, we show for the first time that an intensified membrane reactor without adding an extra catalyst based on internally self-supported nickel hollow fiber membranes (NHFMs) made via a phase inversion–sintering process can resolve this issue. The dense thin layer of the NHFM functioned as an H2-selective membrane to overcome DRM equilibrium limitation by transporting the H2 product from the reaction chamber (tube side) to the permeate zone (shell side), while the porous substrate of the NHFM served as an efficient catalyst bed. At 1000 °C and 14,748 h–1 feed space velocity, the highest H2 production rate of the internally self-supported NHFM reached 20.7 mmol m–2 s–1 with CH4 and CO2 conversions as high as 97.8% and 99.5%, respectively. Throughout this work, the effects of temperature, nitrogen sweep gas flow rate, CO2/CH4 ratio in the feed stream, and feed space velocity on DRM performance are discussed. Notably, we demonstrate that steam can also be used to substitute nitrogen as a sweep gas to generate high-purity H2 product from the membrane reactor. In addition, the DRM performance and structure of internally self-supported NHFM were stable throughout the 180 h (7.5 day) continuous test with thermal cycling of 1000–900–1000–800–1000 °C, highlighting the potential of the robust and stable asymmetric NHFM for DRM industrial application.

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