The CoO/g-C₃N₄p–n heterojunction photocatalysts exhibit enhanced photocatalytic activity and stability under visible light.

A series of ~5 nm sized carbon dots (CDs) with different oxygen contents were fabricated and employed as model material to explore the impact of carbon nanoparticles on rice plant growth. We show that CDs can penetrate into all parts of rice plant including the cell nucleus. Systematic investigations provide insight into the different processes by which seed germination, root elongation, seedling length, enzyme (RuBisCO) activity and carbohydrate generation are increased. CDs entering the cell, reaching the nucleus, loosing the DNA structure, increasing the thionin (Os06g32600) gene expression, which finally enhanced the rice plant disease resistance ability. CDs can be degraded by plant to form plant hormone analogues and CO2, and then the hormone analogues promote the rice plant growth, while the CO2 is converted into carbohydrates through the Calvin cycle of photosynthesis. The outcome of these processes is a 14.8% enhancement of the total rice yield and an increase of the rice plant resistance to diseases.