Libin Zhuang

A Dual-Phase Ceramic Membrane with Extremely High H2 Permeation Flux Prepared by Autoseparation of a Ceramic Precursor

A novel concept for the preparation of multiphase composite ceramics based on demixing of a single ceramic precursor has been developed and used for the synthesis of a dual-phase H2 -permeable ceramic membrane. The precursor BaCe0.5 Fe0.5 O3-δ decomposes on calcination at 1370 °C for 10 h into two thermodynamically stable oxides with perovskite structures: the cerium-rich oxide BaCe0.85 Fe0.15 O3-δ (BCF8515) and the iron-rich oxide BaCe0.15 Fe0.85 O3-δ (BCF1585), 50 mol % each. In the resulting dual-phase material, the orthorhombic perovskite BCF8515 acts as the main proton conductor and the cubic perovskite BCF1585 as the main electron conductor. The dual-phase membrane shows an extremely high H2 permeation flux of 0.76 mL min(-1)  cm(-2) at 950 °C with 1.0 mm thickness. This auto-demixing concept should be applicable to the synthesis of other ionic-electronic conducting ceramics.

Introduction of metal precursors by electrodeposition for the in situ growth of metal–organic framework membranes on porous metal substrates

We report here a facile and efficient electrodeposition method to modify inexpensive porous stainless-steel nets for use as substrates in the in situ growth of metal–organic framework membranes, such as ZIF-8, ZIF-67 and HKUST-1. Using this method, different metal precursors can be electrodeposited depending on the central metals required in the target metal–organic frameworks. The inorganic modifiers prepared by this approach are sufficiently reactive for the one-step growth of continuous metal–organic framework membranes; their reactivity is comparable with that of organic functional groups. The procedure is also green and cost-effective, which is promising for use in large-scale production.

Tuning the separation performance of hydrogen permeable membranes using an anion doping strategy

Overcoming the dilemma between hydrogen permeability and stability is critical for realizing the widespread application of mixed protonic–electronic conducting (MPEC) membranes. Herein, fluoride-anion doping is for the first time reported for tuning the separation performance of MPEC membranes. Lanthanum tungstate oxyfluoride membranes, La5.5W0.6Mo0.4O11.25−δFx (x = 0, 0.025, 0.05, 0.10, 0.20, 0.50), exhibit improved hydrogen permeability and enhanced stability compared to their parent oxides, achieving a maximum value of 0.20 mL min−1 cm−2 at x = 0.05. Moreover, the declining hydrogen permeability performance of lanthanum tungstate MPEC membranes during high-temperature operation was systematically analyzed and relative solutions are put forward. The anion-doping and stability-improving strategies might accelerate the development and future practical applications of MPEC membranes.