Carbon nitride nanosheet/metal–organic framework nanocomposites with synergistic photocatalytic activities

Abstract

Heterogeneous photocatalysis plays a key role in the implementation of novel sustainable technologies, e.g. CO 2 conversion into fuel, H 2 production from water or organics degradation. The progress of photocatalysis relies on the development of tuneable photocatalysts and particularly the ability to build nanocomposites exhibiting synergistic properties with reduced electron-hole recombination rates. We report for the first time the in situ synthesis of nanocomposites of carbon nitride nanosheets (CNNSs) and metal-organic frameworks (MOFs) for application as photocatalysts. This approach leads to the 'nano-scale mixing' of the components, thereby their physical mixture. The nanocomposites retain the high specific surface area and strong visible light absorbance of MIL-100(Fe). The intimate contact between the CNNSs and the MOF particles is found to promote the electron-hole separation significantly due to the formation of a heterojunction. Hence, more efficient photocatalytic dye degradation is achieved over the composites than the physical mixture.

A Facile Synthesis of WS2/g‐C3N4 Composites with Improved Photocatalytic Activity

“…13,18,28 Besides, Figure 8(e) also shows the peaks at 34.7 and 36.9 eV which demonstrate the existence of W +6 due to the partial oxidation of WS 2 during calcination in the preparation of the sample. 31 Figure 9(e) shows that the decomposition of g-C 3 N 4 occurred in the region of 500-600 C which meets the numerous reports for the pure g-C 3 N 4 . It can be seen in Figure 9 that there are two steps of weight loss for all the samples: (i) from room temperature to~150 C and (ii) from approximately 350 to 600 C. The former step may be attributed to evaporation of physically adsorbed water.…”

“…10,13 The thermal properties of materials were also characterized by thermogravimetric analysis (TGA). 31 Interestingly, the decomposition of g-C 3 N 4 in the composites came at the lower temperatures compared to pure g-C 3 N 4 . The later one may come from the WS 2 to WO 3 oxidation (in the temperature range of 350-500 C) 29,30 combined with the decomposition of g-C 3 N 4 (around 550 C).…”

A Facile Method for the Synthesis of a MoS2/g‐C3N4 Photocatalyst

“…a demonstrates that there are two steps of weight loss for all samples: (i) from room temperature to ∼150 °C and (ii) from ∼400 to 625 °C. The former step may be attributed to evaporation of physically adsorbed water and the latter was the decomposition of the materials, in which the CN's decomposition temperature meets the literature value for the pure g‐C 3 N 4 .…”

“…Interestingly, the decomposition of the composites occurs at the lower temperature compared to CN, and this trend of decreasing the decomposition temperature when raising the MoS 2 content of the composites can be observed in all samples. This phenomenon was found in some reports , and is explained by the catalytic role of MoS 2 or the disturbing effect of MoS 2 to the interlayer stacking structure of g‐C 3 N 4 .…”

Photocatalysts with adsorption property for dye-contaminated water purification

“…Therefore, metal organic frameworks (MOFs) having porous structure character with the high specific surface area was used for compositing with g-C3N4. 207 This kind of MOF/CN heterojunction nanocomposites have been proved with enhanced photocatalytic degradation effect because of firstly enhanced reactant/catalyst interaction via adsorption and secondly inhibited electron-hole recombination. A homogeneous well-mixed structure was the key factor in improving photodegradation effect.…”