Unleashing Platinum‐Sulfur Synergy in Ultranano‐Structured Conjugated Porous Polymers Based on Thiazole for Efficient Hydrogen Generation

The molecular design of conjugated porous polymers (CPPs) offers a powerful strategy to control their optoelectronic properties and interactions with semiconductor and metallic cocatalyst interfaces. Here, we develop an ultrananostructured thiazolo[5,4‐d]thiazole (TzTz)‐based CPP (UN_IEP‐48), whose sulfur‐containing units provide favourable sites for interaction with Pt. High‐performance microfluidic processing enables its intimate integration with TiO 2 , yielding an optimized UN_IEP‐48@T3 hybrid containing only 3 wt.% polymer. Photoluminescence and transient absorption spectroscopy reveal efficient charge separation consistent with a direct Z‐scheme mechanism, directing the reduction pathway toward the CPP. Remarkably, photodeposition of only 0.5 wt.% Pt increases the H 2 evolution rate from 3.0 to 94.3 mmol g −1 h −1 , corresponding to a 30‐fold enhancement and a photonic efficiency of 34.91%. Increasing Pt loading to 1 wt.% provides essentially no further improvement, highlighting efficient noble‐metal utilization. Microscopy reveals preferential Pt localization on polymer‐rich regions, while FTIR, XPS, and electrochemical impedance measurements support strong Pt–TzTz interactions and facilitated electron transfer. These results demonstrate how molecular engineering of CPPs can couple nanoscale heterojunction formation with cocatalyst interfacial chemistry, maximizing photocatalytic H 2 production while minimizing noble‐metal loading.