Carbon Quantum Dot-Modified and Chloride-Doped Ordered Macroporous Graphitic Carbon Nitride Composites for Hydrogen Evolution

Abstract

The photocatalytic water-splitting hydrogen evolution technology has the potential to relieve energy crisis and enhance the hydrogen generation efficiency of the catalyst. Herein, a kind of 3DOM-CN composite, which is composed of a three-dimensional ordered macroporous material based on g-C3N4, was synthesized through a colloidal template crystal method. After it was doped with Cl– and modified by carbon quantum dots (CQDs), the as-prepared xCQDs/Cl/3DOM-CN composite showed an evident hydrogen generation ability enhancement irradiated by visible light. The structures, composition, and optical and electrochemical properties of the prepared photocatalysts were comprehensively obtained by transmission electron microscopy (TEM), scanning electron microscopy, high-resolution-TEM, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV–vis, electrochemical impedance spectroscopy, photocurrent, Mott–Schottky, and photoluminescence. The highest hydrogen evolution efficiency under visible-light irradiation was achieved by the 1%CQDs/Cl/3DOM-CN composite with a hydrogen generation rate of 8.12 mmol g–1 h–1, which was nearly five times that of the 3DOM-CN. The photocatalyst exhibited an outstanding stability and reusability after four cycles. Eventually, the mechanism in the process of catalytic hydrogen production was briefly discussed. The synergy of the multiple functions of the CQDs/Cl/3DOM-CN composite offered a technique for enhancing the activity of the photocatalysts in the photocatalytic water-splitting process.

Pumping with Modified Polyurethane Sponge: An Alternative Technology for Removing Oil Spills from Water Surface

“…The modified sponge has specific surface area and pore size of 14.48 m 2 g −1 and 140.8 nm, respectively. These large specific surface area and pore size indicate that C‐PDMS‐PU has a honeycomb macroporous structure, which provides the necessary conditions for the storage of oil [26,27] . The same finding can be observed from the SEM image.…”

“…These large specific surface area and pore size indicate that C-PDMS-PU has a honeycomb macroporous structure, which provides the necessary conditions for the storage of oil. [26,27] The same finding can be observed from the SEM image.…”

Improvement of Permeability and Antifouling Properties of Polyamide Thin-Film Nanocomposite Nanofiltration Membranes Using Boron Nitride Quantum Dots

“…This can enhance the electrostatic repulsion between the membrane surface and foulants, reducing fouling and improving the membrane's performance. 22,43,44 3.2. Characterization of Membrane.…”

Cadmium Sulfide 3D Photonic Crystal with Hierarchically Ordered Macropores for Highly Efficient Photocatalytic Hydrogen Generation

“…Moreover, modifications to the pore walls mostly do not change the 3DOM structure, which readily allows other catalytic effects. To date, many kinds of oxygenated compounds and carbon and nitrogen compounds, such as BiFeO 3 , WO 3 , TiO 2 , SrTiO 3 , and g-C 3 N 4 , are designed into the 3DOM structure for improving photocatalytic performance. However, Zhang et al deposited thioglycolic acid-modified CdS nanocrystals on quartz sheets by a coassembly method to form an inverse opal CdS film, and it exhibited enhancement of photocatalytic H 2 production rates.…”

“…27 WO 3 ,28 TiO 2 ,29 SrTiO 3 , 30 and g-C 3 N 4 ,31 are designed into the 3DOM structure for improving photocatalytic performance. However, Zhang et al deposited thioglycolic acid-modified CdS nanocrystals on quartz sheets by a coassembly method to form an inverse opal CdS film,32 and it exhibited enhancement of photocatalytic H 2 production rates.…”