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Recent progress in conjugated polymer photocatalysts has opened avenues for enhancing photocatalytic hydrogen production (PHP) activity through structural design. This study highlights the impact of the acceptor-to-donor feed ratio on PHP activity in copolymers, influencing their energy level structures. Five conjugated porous polymers (CPPs) were synthesized by adjusting the acceptor-to-donor molar ratio. Notably, at a 2:1 acceptor-to-donor ratio, the polymer demonstrated a high hydrogen evolution rate (HER) of 61.9 mmol g−1 h−1 under full arc irradiation without co-catalysts and an apparent quantum yield (AQY) of 7.77% at 475 nm. However, further increasing the proportion of the donor unit in the copolymers decreases their HER. Experiments and theoretical simulation characterized that the feed ratios effectively tune the polymer's molecular structure, hydrophilicity, band gap, and the generation and transport efficiency of photo-induced charge carriers, ultimately affecting the hydrogen production kinetics and efficiency. This research demonstrates that tuning the band structure and chemical compositions of CPPs through statistical copolymerization significantly impacts their PHP activity. [Display omitted] • Conjugated porous polymers (CPPs) with donor-acceptor type were prepared as photocatalysts. • PProDOT-didecyl was used as the donor unit to tune the energy levels of the CPPs. • BS-4 shows an impressive hydrogen evolution rate of 61.9 mmol g−1 h−1 under full arc free of co-catalyst. • The optimum donor-to-acceptor ratio is crucial for improved photocatalytic activity. [ABSTRACT FROM AUTHOR]

Donor-acceptor conjugated polymers have received significant attention as the most promising photocatalysts for efficient photocatalytic hydrogen production (PHP). Nonetheless, achieving high photocatalytic PHP performance relies on molecular framework design and the judicious selection of different structural units. Herein, benzotrithiophene (BTT) and triazine derivatives were used as the basic units of organic polymers, and two conjugated porous polymers (CPPs) named as CP1 and CP2 were successfully synthesized by Stille coupling reaction. Compared with benzene as the linkage unit of triazine, it is evident that the incorporation of the thiophene unit in CP2 broadens its light response range, and promotes the generation of electrons/holes induced by light. Density functional theory (DFT) calculations and femtosecond transient absorption(fs-TA) spectroscopy reveal that CP2 effectively inhibits the photogenerated electron-hole pair recombination and promotes carrier transport. Remarkably, CP2 with Pt co-catalyst exhibited a notably superior PHP performance compared with that of CP1 polymer, which achieved an impressive hydrogen evolution rate (HER) of 21702.4 μmol/g/h, surpassing CP1 by approximately 3.7 times. This work provides a new tactic for enhancing the intrinsic PHP activity and reveals the underlying mechanism for the enhanced photocatalytic activity by regulating the different structural units of the donor-acceptor conjugated polymers. [Display omitted] • Two conjugated porous polymers were constructed based on benzotrithiophen and triazine derivatives. • Polymers CP1 and CP2 were prepared from benzene and thiophene linked triazine derivatives, respectively. • The different linkage units contribute to the great difference in photocatalytic performance. • CP2 exhibited an ultrahigh hydrogen evolution rate 21702.4 μmol/g/h. • The thiophene unit in CP2 suppress recombination of photo-induced charge carriers and promote transport. [ABSTRACT FROM AUTHOR]

Exploring efficient and stable TiO 2 -based photocatalysts for visible-light H 2 evolution remains a great challenge. Here, a novel ternary heterojunction (THSO/Au@TiO 2) was successfully synthesized by a facile in-situ polymerization strategy, which showed highly enhanced photocatalytic activity towards H 2 evolution under visible light. The optimized THSO/Au@TiO 2 -26 exhibited an excellent photocatalytic performance to H 2 evolution (7504 μmol/g/h), which was 16.31, 416.89 and 1.81 times higher than that of THSO, TiO 2 and THSO/TiO 2 photocatalysts, respectively. This excellent performance should be attributed to the excellent visible light absorption ability of the polymer THSO, and the local surface plasmonic resonance effect of Au nanoparticles (Au NPs), promoting separation and transfer of photo-generated charge carriers. This work presents new insights for the design of efficient and rational TiO 2 -based photocatalytic systems to enhance photocatalytic performance towards H 2 evolution under visible light. [Display omitted] • A heterojunction was fabricated by coating conjugated polymer (THSO) on Au@TiO 2 composite nanoparticles. • The THSO/Au@TiO 2 heterojunction showed a high hydrogen evolution rate and stability. • The high photocatalytic activity of THSO/Au@TiO 2 was due to its unique ternary heterostructure configuration. • The multi-functional roles of Au nanoparticles in enhancing photocatalytic performance were revealed. [ABSTRACT FROM AUTHOR]