ZIF‐67‐Confined Pd Single‐Atom Catalysts Implanted Into Polydopamine‐Modified Bamboo Microchannels for Robust Continuous‐Flow Hydrogenation

Abstract Developing efficient catalytic hydrogenation microreactors with minimal catalyst loading yet high active‐site density for treating concentrated organic pollutants remains challenging. Herein, a facile room‐temperature method is presented to stabilize Pd single‐atom catalysts (SACs) within ZIF‐67 crystals during their formation, aiming to fabricate an efficient, low‐loading hydrogenation catalytic microreactor (Pd@Z‐P/b CMR). ZIF‐67 is constructed into polydopamine (PDA)‐modified bamboo microchannels under flow conditions, utilizing preimmobilized Co 2+ seeds in PDA. Despite an ultralow Pd loading (0.0014 wt.%), the Pd@Z‐P/b CMR featuring atomically dispersed Pd─N 4 sites in ZIF‐67 considerably outperforms its Pd nanoparticle–loaded counterpart (Pd 0.0035 wt.%) in continuous‐flow hydrogenation, demonstrating superior robustness and maximized Pd utilization with 94.3% conversion efficiency for saturated 4‐nitroaniline over 10 d and 97.5% conversion efficiency for gram‐level methylene blue (1.0 g L −1 ) over 5 d. Crucially, it exhibits consistent, high performance in real environmental water samples. The high surface area and porosity of ZIF‐67 stabilize the Pd SACs, enhance dispersion, and ensure accessibility. Simultaneously, the Pd─N 4 configuration facilitates electron transfer and optimizes hydrogen binding energy, dramatically boosting the catalytic activity. This work provides a novel strategy for room‐temperature SAC synthesis and the effective treatment of high‐concentration organic pollutants for sustainable wastewater remediation.