Bimetallic catalytic ceramic membrane for sustained water purification: Role of Cu in stabilizing reduced Co centers

The development of multifunctional catalytic membranes that concurrently enable rapid contaminant degradation, antifouling resistance, and long-term operational stability remains a critical challenge in advanced water treatment. Here, we describe the preparation and testing of a rationally engineered bimetallic CoCu catalyst, anchored onto graphitic carbon nitride (g-C 3 N 4 ) via a glucose-mediated cascade anchoring method (CoCu-CN), and immobilized on to an alumina ceramic membrane (CoCu-CN/M). Atomic-level characterizations revealed the coexistence of surface Co N 4 species and bulk Co Co coordination, and the electron-donating effect of Cu species stabilizes Co in an absolutely reduced state (Co 0 /Co-N 4 ). This bimetallic configuration optimized the peroxymonosulfate (PMS) adsorption configuration ( E ads  = −3.05 eV) and facilitated O O oxygen bond cleavage ( I O O  = 1.477 Å), thereby accelerating the generation of reactive oxygen species, including SO 4 − , O 2 − , and 1 O 2 . Consequently, the CoCu-CN system achieved complete degradation of a target pollutant carbamazepine (CBZ), with a reaction rate constant (k obs ) of 0.755 min −1 , corresponding to 158.9-fold and 3.23-fold enhancements compared to the monometallic Cu-CN and Co-CN systems, respectively. The CoCu-CN/M membrane demonstrated a high permeability (404.72 LMH/bar), sustained >98% CBZ removal over seven cycles, and exhibited strong antifouling performance. In surface water, the novel membrane maintained >95% degradation efficiency over 72 h of continuous operation, confirming its long-term stability. This study provides atomic-level insights into bimetallic catalytic activation and proposes an effective membrane-based solution for advanced water treatment.