Doping Carbon Nitride Quantum Dots into Melamine‐Silver Matrix: An Efficient Photocatalyst with Tunable Morphology and Photocatalysis for H₂O₂ Evolution under Visible Light

Abstract

Carbon nitride quantum dots (CNQDs) were doped into melamine (MA) and silver (Ag) matrix yielding CNQDs@MA−Ag nanocomposites by the supramolecular self‐assembly route. To our surprise, the resulting mesoporous nanocomposites could present different morphologies (i. e., nanowires, nanoflowers, and nanosheets) and especially tunable visible‐light photocatalysis performances depending on the percentages of CNQDs used. It was discovered that the CNQDs@MA−Ag ones with the pinecone‐like structure (containing 30 % CNQDs) could exhibit the strongest visible‐light photocatalysis for splitting water to yield H2O2 with a production efficiency of 39.82 μmol ⋅ g−1 h−1, which is more than ten‐fold higher than that of CNQDs alone. Herein, the nano‐scaled Ag could facilitate the increased light harvesting and the separation as well as transmission of electron‐hole pairs of CNQDs resulting in the enhanced visible‐light photocatalysis of nanocomposites. More importantly, the pinecone‐like ones might additionally enable more exposed active sites of photocatalysis and larger mesoporous specific area of contacting dissolved oxygen in water, leading to the higher photocatalytic efficiency of H2O2 generation. This CNQDs‐based fabrication strategy may open a new door towards the design of a variety of photocatalysts with different morphologies and tunable photocatalysis performances for the efficient splitting water toward H2O2 evolution under sunlight.

Defect Control via Compositional Engineering of Zn-Cu-In-S Alloyed QDs for Photocatalytic H2O2 Generation and Micropollutant Degradation: Affecting Parameters, Kinetics, and Insightful Mechanism

“…From the figure, it is clear that there is a two-step weight loss of 18 and 4% at about 75–108 and 245–281 °C, respectively. The first weight loss may be due to the evaporation of moisture and other organic solvents, and the second mass loss can be attributed to the detachment of thiol (TGA) ligands present in the ZCIS-2 moiety, indicating better stability of the QD up to 600 °C. , Furthermore, a comparison plot for H 2 O 2 evolution and CIP degradation of various photocatalysts is given in Figure , which shows the superiority of the present work (ZCIS QD) over other QD systems previously reported. − …”

Solar‐Driven Photocatalytic Disinfection Over 2D Semiconductors: The Generation and Effects of Reactive Oxygen Species

“…g‐C 3 N 4 , in the form of quantum dots, was hybridized with melamine–Ag matrix to form a flower‐like structure. [ 206 ] The composite displaying more active sites and a large surface area drove a tenfold increase in H 2 O 2 generation efficiency, compared with pure g‐C 3 N 4 quantum dots. In another work, porous g‐C 3 N 4 sheets were coupled with Mxene (Ti 3 C 2 ) to form a Schottky junction of face‐to‐face structures (Figure 10c).…”

Application of coal-based carbon dots for photocatalysis and energy storage: a minireview

“…3 Currently, extensive attention has been paid to CDs owing to their several advantages, such as abundant carbon source, low cost, excellent biocompatibility, 4,5 water solubility, [6][7][8] and fascinating fluorescent properties. [9][10][11] Additionally, CDs are widely applied for bioimaging, [12][13][14][15] sensing, [16][17][18][19] lubrication, 20 solar cells, [21][22][23] catalysis, [24][25][26][27] batteries, 28,29 etc. Various carbon materials can be adopted to prepare CDs, such as graphite, 30 graphene, 31 glucose, 32 carbon nanotubes and carbon fibers, 33,34 and citric acid, 35,36 and even biomass like the leaves 37,38 and fruits of plants.…”