Recyclable porous PMMA fibers membrane immobilized with SnO2@ZnO-CN heterojunction for high-performance visible-light photocatalytic CO2 reduction

Abstract

Photocatalytic CO2 reduction holds great promise for carbon recycling, yet conventional powder photocatalysts are limited by narrow light response range, high carrier recombination rate, and poor recyclability. Herein, a synergistic optimization strategy combining heterojunction construction and porous support engineering was proposed to tackle these challenges. SnO2@ZnO-CN heterojunction was synthesized via mechanical grinding and calcination, and further immobilized into porous PMMA/ZnCl2@SnO2/ZnO-CN fibers membrane through electrospinning with water-induced phase separation. The Type-II band matching between SnO2 and ZnO-CN extends light response to the visible region and enhances carrier separation efficiency. The optimized powder catalyst achieves CO and C2H6 production rates of 45.72 and 9.16 μmol·g−1·h−1 with 75% CO selectivity, maintaining over 95% activity after 4 cycles. The porous fiber membrane reaches a total yield of 56.46 μmol·g−1·h−1 for CO2 reduction with 3.42-fold than dense fibers, keeping ≤4% activity decay after 4 cycles and eliminating powder loss. This work provides an eco-friendly solution for the engineering application of photocatalytic CO2 reduction.