Sub-melting-point sintering of CuO–SiC catalytic membranes for simultaneous acetone and PM_2.5 control

CuO has been shown to effectively lower the sintering temperature of SiC membranes to 1040 °C through its melting flow, which promotes the rearrangement of SiC particles and significantly reduces energy consumption. However, the uncontrolled migration of molten CuO to the surface causes densification of the separation layer. Additionally, incomplete filling of the support's open pores results in the penetration of fine SiC particles, which ultimately reduces the gas permeance of the SiC catalytic membranes. Herein, we developed a sub-melting-point sintering (SMPS) method to fabricate continuous and porous CuO–SiC catalytic membranes with high gas permeance (354.90 m³ m⁻² h⁻¹ kPa⁻¹, average pore size of 5.4 μm) and significantly reduced energy consumption during sintering. The use of methyl cellulose (MC) suspension effectively fills the open pores of the CuO–SiC support, ensuring the separation layer's structural integrity while eliminating the need for an intermediate layer. Additionally, the introduction of liquid water glass (LWG) as a sintering additive allows sintering of the separation layer at 850 °C, substantially below the melting point of CuO. This suppresses the upward migration of molten CuO and further reduces overall sintering energy consumption. An acid etching approach exposes CuO nanoparticles rich in oxygen vacancies within the CuO–SiC catalytic membrane, enabling complete acetone oxidation at 240 °C and achieving a 100 % filtration efficiency for PM_2.5. This strategy effectively addresses the challenges of separation layer densification, particle penetration, and high energy requirements, offering valuable insights for the design of advanced CuO-based catalytic membranes.