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Atomically precise Ni 6 (SC 2 H 4 Ph) 12 nanoclusters (Ni 6 NCs) supported on g-C 3 N 4 nanosheets were constructed to enhance the photocatalytic hydrogen evolution performances. [Display omitted] Much effort has been devoted to improving the photocatalytic capacity of graphitic carbon nitride (g-C 3 N 4). In this paper, we reported the successful synthesis of a hybrid photocatalyst with superb photocatalytic hydrogen production activity through decorating atomically precise Ni 6 (SC 2 H 4 Ph) 12 nanoclusters on g-C 3 N 4 nanosheets (labeled as Ni 6 /g-C 3 N 4) at room temperature. Zeta potential experiments demonstrated that the electrostatic interaction between Ni 6 and g-C 3 N 4 led to the formation of Ni 6 /g-C 3 N 4. The photocatalytic measurements revealed that the 5 %-Ni 6 /g-C 3 N 4 prepared with the original mass ratio of m(Ni 6)/m(g-C 3 N 4) = 1/20 exhibited the strongest hydrogen production activity. In the system with triethanolamine (TEOA) as the sacrifice agent, the visible-light hydrogen production rate reached up to 5.87 mmol h−1 g−1, approximately 290 times higher than that of pure g-C 3 N 4 (0.02 mmol h−1 g−1). Density functional theory (DFT) calculations testified that the above significant enhancement of photocatalytic hydrogen evolution of the hybrid photocatalyst arose from the photogenerated electrons transfer from Ni 6 to g-C 3 N 4. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure evolution of polymeric carbon nitride was investigated and Au ions was used to improve its photocatalytic efficiency. Their structures were investigated by FT-IR, XPS, XRD, SEM and TEM. Their specific surface area and aperture distribution were measured by BET. Meanwhile, the energy band structure and electron-hole separation efficiency were analyzed by UV–Vis and PL spectroscopy. In addition, the photocatalytic performance of the photocatalysts was assessed by photocatalytic degradation of RhB and photocatalytic hydrogen evolution. The results showed that 600-PCN possessed the best photocatalytic performance, with a degradation rate of 46.92 % in 150 min. What's more, the degradation rate of RhB solution by 2 % Au/PCN reached 47.88 %, which was 2.17 times higher than that of 550-PCN (22.01 %). During the degradation process, h+ oxidatively degrade RhB. The hydrogen production rate of 2 % Au/PCN was about 11.658 μmol/g/h, which was 41.23 times higher than that of 550-PCN (0.282 μmol/g/h). • PCN is basically formed at 500 oC, but 600-PCN has better photocatalytic performance. • 2.0 % Au/PCN showed the best hydrogen production performance, with a hydrogen production rate of about 11.658 μmol/g/h. • 2.0 % Au/PCN showed the highest degradation rate of RhB solution with 47.88 %, and the main active substance is h+. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride is considered as an ideal semiconductor material for photocatalytic hydrogen evolution due to its suitable energy band structure, durability and environmental friendliness. To further improve the catalytic performance of g-C3N4, nickel phosphide-loaded one-dimensional tubular carbon nitride (Ni2P/TCN) was prepared by thermal polymerization and photo deposition. The beneficial effect of the one-dimensional tubular structure on hydrogen generation was mainly attributed to its larger specific surface area (increased light absorption) as well as the linear movement of the carriers, which reduced their diffusion distance to the surface and facilitated the separation of photogenerated carriers. The loading of Ni2P co-catalyst improved the visible light utilization efficiency and enabled the migration of photogenerated electrons towards Ni2P, which ultimately reacted with the enhanced adsorbed H+ on the Ni2P surface to facilitate the photocatalytic hydrogen evolution process. This study provides new clues for the further development of efficient, environmentally friendly and low-cost g-C3N4 catalysts. [ABSTRACT FROM AUTHOR]

P-doped graphitic carbon nitride tubes (P-CNTS) with different P concentrations were successfully fabricated via a pre-hydrothermal in combination with a calcination process under a nitrogen atmosphere. The as-prepared samples exhibited excellent photocatalytic performance with a hydrogen production rate (HPR) of 2749.3 μmol g−1 h−1, which was 17.5 and 6.6 times higher than that of the bulk graphitic carbon nitride (CNB) and graphitic carbon nitride tube (CNT). The structural and textural properties of the P-CNT samples were well-investigated via a series of characterization methods. Compared with the bulk g-C3N4, the tubular structure of the doped samples was provided with a larger specific surface area (SSA) and a relatively rough interior. Besides the above, surface defects were formed due to the doping, which could act as more active sites for the hydrogen production reaction. In addition, the introduction of the P element could effectively adjust the band-gap, strengthen the harvest of visible-light, and boost the effective separation of photogenerated charges. More interestingly, these findings can open up a novel prospect for the enhancement of the photocatalytic performance of the modified g-C3N4. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oxygen-doped crystalline carbon nitride (CCNO) was successfully synthesized. • Pharmaceuticals and personal care products (PPCPs) were readily degraded by CCNO. • Hydrogen fuel was recovered from photocatalytic degradation of PPCPs by CCNO. • An energy-recovering wastewater treatment process using solar energy is proposed. Degrading organic pollutants while generating hydrogen from water splitting is an ideal application of photocatalysis. Herein, we presented an efficient photocatalyst, oxygen-doped crystalline carbon nitride, to power the degradation of various kinds of pharmaceuticals and personal care products and the simultaneous hydrogen production. The highest efficiency was achieved in treating the simulated wastewater containing naproxen (NPX), with the H 2 evolution rate of 819.1 µmol/g/h and the NPX degradation efficiency of 92 % upon visible light irradiation. Experimental and computational results suggested that the doped oxygen atoms thermodynamically favored the generation of hydroxyl peroxide for pollutant degradation and lowered the energy barrier of H 2 O reduction to produce hydrogen fuel. Most importantly, the catalysts functioned well in the natural aquatic environment including sea water, sewage water, river water, and well water. This study provides fundamental insights into photocatalytic water treatment with simultaneous hydrogen production, indicating an energy-recovering approach for wastewater treatment. [ABSTRACT FROM AUTHOR]