Linear conjugated polymer photocatalysts remain suffer from insufficient near-infrared light absorption and poor photogenerated-carriers separation efficiency caused by twisted backbone, limiting their further application for photocatalytic water splitting to produce hydrogen energy. Herein, we first synthesized crystallized 2D poly(thiophene-co-nitrothiophene) (PN) with narrow band gap through direct (hetero) arylation polymerization (DHAP) method, then constructed dimension-matching PN/graphitic carbon nitride (CN) heterojunctions (PN/CN) with 2D/2D structure for visible/near-infrared light photocatalytic hydrogen production. The resulting 2D/2D heterojunctions exhibit excellent visible/near-infrared light absorption and photocatalytic activates. The ratio-optimized 15PN/CN shows boosting hydrogen production activity up to 11.73 mmol/hg−1 under visible/near-infrared light (λ > 420 nm) irradiation, which is ∼ 30-time and ∼ 46.9-time improvement than that of PN and CN separately. Notably, the apparent quantum yield (AQY) of 15PN/CN is calculated to be 2.35 % at 700 nm and 0.62 % at 800 nm. It is proved that the π − π interaction of dimension-matching heterojunctions between PN and CN facilitates electrons transfer from LUMO of PN to LUMO of CN. This study provides another new train of thought for reasonably developing dimension-matching polymer heterojunctions by manipulating crystallinity and band structure of linear conjugated polymers for efficient visible/near-infrared light photocatalytic hydrogen production.

中文翻译：

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尺寸匹配的结晶线性共轭聚合物/石墨氮化碳异质结，用于促进可见光/近红外光催化制氢


线性共轭聚合物光催化剂仍然存在近红外光吸收不足和扭曲主链导致光生载流子分离效率差的问题，限制了它们在光催化分解水生产氢能方面的进一步应用。在此，我们首先通过直接（异质）芳基化聚合 （DHAP） 方法合成了具有窄带隙的结晶 2D 聚（噻吩-共硝基噻吩）（PN），然后构建了尺寸匹配的 PN/石墨氮化碳 （CN） 异质结 （PN/CN），具有 2D/2D 结构，用于可见光/近红外光催化制氢。所得的 2D/2D 异质结表现出优异的可见光/近红外光吸收和光催化活化。比率优化的 15PN/CN 显示，在可见光/近红外光 （λ > 420 nm） 照射下，制氢活性提高到 11.73 mmol/hg-1，比 PN 和 CN 分别提高了 ∼ 30 倍和 ∼ 46.9 倍。值得注意的是，15PN/CN 的表观量子产率 （AQY） 计算在 700 nm 处为 2.35 %，在 800 nm 处为 0.62 %。事实证明，PN 和 CN 之间维度匹配的异质结的 π − π 相互作用促进了电子从 PN 的 LUMO 转移到 CN 的 LUMO中。本研究为通过操纵线性共轭聚合物的结晶度和能带结构来合理开发尺寸匹配的聚合物异质结提供了另一种新的思路，以实现高效的可见光/近红外光催化制氢。