Solar H₂O₂ produced by O₂ reduction provides a green, efficient, and ecological alternative to the industrial anthraquinone process and H₂/O₂ direct-synthesis. We report efficient photocatalytic H₂O₂ production at a rate of 73.4 mM h^–1 in the presence of a sacrificial donor on a structurally engineered catalyst, alkali metal-halide modulated poly(heptazine imide) (MX → PHI). The reported H₂O₂ production is nearly 150 and >4250 times higher than triazine structured pristine carbon nitride under UV–visible and visible light (≥400 nm) irradiation, respectively. Furthermore, the solar H₂O₂ production rate on MX → PHI is higher than most of the previously reported carbon nitride (triazine, tri-s-triazine), metal oxides, metal sulfides, and other metal–organic photocatalysts. A record high AQY of 96% at 365 nm and 21% at 450 nm was observed. We find that structural modulation by alkali metal-halides results in a highly photoactive MX → PHI catalyst which has a broader light absorption range, enhanced light absorption ability, tailored bandgap, and a tunable band edge position. Moreover, this material has a different polymeric structure, high O₂ trapping ability, interlayer intercalation, as well as surface decoration of alkali metals. The specific C≡N groups and surface defects, generated by intercalated MX, were also considered as potential contributors to the separation of photoinduced electron–hole pairs, leading to enhanced photocatalytic activity. A synergy of all these factors contributes to a higher H₂O₂ production rate. Spectroscopic data help us to rationalize the exceptional photochemical performance and structural characteristics of MX → PHI.

中文翻译：

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在结构改性的聚（庚嗪酰亚胺）上通过光催化 O2 还原增强 H2O2 的生产

通过O ₂还原产生的太阳能H ₂ O _{2为工业蒽醌法和H 2} /O ₂直接合成提供了一种绿色、高效、生态的替代方案。我们报告了在结构工程催化剂碱金属卤化物调制的聚（庚嗪酰亚胺）（MX → PHI）上存在牺牲供体的情况下，以73.4 mM h ^-1的速率高效光催化 H ₂ O _2生产。报告的 H ₂ O ₂在紫外-可见光和可见光（≥400 nm）照射下，产量分别比三嗪结构的原始氮化碳高出近 150 倍和 > 4250 倍。此外，MX → PHI 上的太阳能 H ₂ O ₂产率高于大多数先前报道的氮化碳（三嗪、三-s-三嗪）、金属氧化物、金属硫化物和其他金属有机光催化剂。在 365 nm 处观察到创纪录的 96% 和在 450 nm 处 21% 的 AQY。我们发现碱金属卤化物的结构调制产生了高光活性的 MX → PHI 催化剂，该催化剂具有更宽的光吸收范围、增强的光吸收能力、定制的带隙和可调的带边位置。此外，这种材料具有不同的聚合结构，高 O ₂捕集能力，层间插层，以及碱金属的表面装饰。由嵌入的 MX 产生的特定 C≡N 基团和表面缺陷也被认为是光致电子-空穴对分离的潜在贡献者，从而提高了光催化活性。所有这些因素的协同作用有助于提高 H ₂ O ₂产率。光谱数据帮助我们合理化 MX → PHI 的特殊光化学性能和结构特征。