Harnessing Photocatalytic and Photothermal Effects of C-Doped Graphitic Carbon Nitride for Efficient Bacterial Disinfection

Donor-acceptor engineered g-C3N4 enabling peroxymonosulfate photocatalytic conversion to 1O2 with nearly 100% selectivity

Singlet oxygen (¹O₂) is a thrilling active species for selectively oxidating organic substances. However, the efficient and selective generation of ¹O₂ maintains a great challenge. Here, we develop a donor-acceptor structured g-C₃N₄ by covalently engineering benzenetricarboxaldehyde (BTA) onto the fringe of g-C₃N₄. The g-C₃N₄-BTA exerts high-efficiency ¹O₂ generation with nearly 100% selectivity via peroxymonosulfate (PMS) photocatalytic activation upon visible light illumination, exhibiting obviously boosted efficiency for selective elimination of atrazine (ATZ). The consequences of experiments and theoretical calculations demonstrate that BTA units serve as electron-withdrawing sites to trap photogenerated electrons and facilitate the adsorption of PMS on the electron-deficient heptazine rings of g-C₃N₄. As such, PMS can be in-situ oxidated by the photogenerated holes to selectively produce ¹O₂. Besides, the g-C₃N₄-BTA/PMS system delivers high stability and strong resistance to the coexisting organic ions and natural organic matter, demonstrating great potential for selectively removing targeted organic contaminants with high efficiency.

Solar-to-H2 O2 Energy Conversion by the Photothermal Effect of a Polymeric Photocatalyst via a Two-Channel Pathway

With a view to using solar energy, the exploitation of near-infrared (NIR) light, which constitutes about 50 % of solar energy, in photocatalytic H₂ O₂ synthesis remains challenging. In this study, resorcinol-formaldehyde (RF), which has a relatively low bandgap and high conductivity, is introduced for photothermal catalytic generation of H₂ O₂ under ambient conditions. Owing to the promoted surface charge transfer rate under high temperature, the photosynthetic yield reaches roughly 2000 μm within 40 min under 400 mW cm^-2 irradiation with a solar-to-chemical conversion (SCC) efficiency of up to 0.19 % at 338 K under ambient conditions, exceeding the rate of photocatalysis with a cooling system by a factor of about 2.5. Notably, the H₂ O₂ produced by RF during photothermal process was formed via a two-channel pathway, leading to the overall promotion of H₂ O₂ formation. The resultant H₂ O₂ can be applied in situ for pollutant removal. This work offers a sustainable and economical route for the efficient formation of H₂ O₂ .

3D macroporous CUPC/g-C3N4 heterostructured composites for highly efficient multifunctional solar evaporation

Solar-driven interfacial evaporation is a promising technology for water recycling and purification. A sustainable solar evaporation material should have not only high photothermal conversion efficiency, but also an ecofriendly fabrication process as well as pollutant degradation and sterilization properties. We present in this work a solar evaporator based on graphitic carbon nitride (g-C₃N₄) and copper phthalocyanine (CUPC) composites with typical type-I heterojunctions. Superhydrophilic three-dimensional macroporous g-C₃N₄ was obtained by self-assembly of precursors in aqueous solution followed by thermal polycondensation. By adding various weight ratios (0.15%, 1.5% and 7.5%) of CUPC, the composites exhibited a strong absorption in the region of red and infrared light. The CUPC-CN 7.5% composite achieved a photothermal conversion efficiency of 98.5% in nanofluids with an interfacial solar evaporation efficiency of 93.6% for artificial sea water and 98.7% for deionized water, which are among the highest reported to date. Besides, the composite materials demonstrated superior water purification capabilities by decomposing dye molecules and E. coli bacteria in aqueous solution. Our work established a novel approach for the development of multifunctional interfacial evaporators based on macroporous organic semiconductor heterostructures.