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The design and development of efficient nitride photocatalysts have attracted much attention. Herein, two-dimensional mesoporous Ta 3 N 5 is successfully synthesized through a simple sol-gel process with filter paper as a biological template and a combination of vacuum nitriding reactions. The prepared Ta 3 N 5 shows a wide light response range up to the near infrared (NIR) region due to the nitrogen vacancies generated from substitution of N3− for O2− ions during vacuum nitridation. Significantly, such a narrow bandgap (∼1.99 eV) still satisfies the redox potential of water splitting in thermodynamics. The experimental results show that the Ta 3 N 5 photocatalyst exhibits an enhanced hydrogen production rate of 34.6 μmol h−1 g−1, which is 3.9 and 2.1 times higher than that of Ta 2 O 5 and partial nitridation of Ta 2 O 5 (N–Ta 2 O 5), respectively. This enhanced photocatalytic performance could be attributed to the high specific surface area to provide reactive active sites, substitution of N3− for O2− ions to optimize the band structure, and special two-dimensional mesoporous structure to shorten the charge transfer distance. This work provides a new perspective for the preparation of two-dimensional nitride materials by a biological template method combining vacuum nitriding with enhanced photocatalytic performance. Two-dimensional mesoporous Ta 3 N 5 is synthesized by a simple sol-gel process with filter paper as a biological template and vacuum nitriding reaction, leading to an efficient photocatalytic performance. [Display omitted] • Two-dimensional mesoporous Ta 3 N 5 was prepared by a biological template. • The prepared Ta 3 N 5 shows a wide light response range up to the near infrared region. • The special two-dimensional structure shortens the charge transfer distance. • The Ta 3 N 5 photocatalyst shows a superior hydrogen production performance. [ABSTRACT FROM AUTHOR]

N-rich precursors govern the thermal polymerization formation of graphitic carbon nitride (g-C 3 N 4) based catalysts towards enhanced photocatalytic performance. In this paper, Cu components were introduced in superior thin g-C 3 N 4 nanosheets using the thermal polymerization copper acetate and bulk g-C 3 N 4 created by different precursors including melamine, dicyandiamide, and thiourea, such as melamine-g-C 3 N 4 (MCN), dicyandiamide-g-C 3 N 4 (DCN), and thiourea-g-C 3 N 4 (TCN). The performance of Cu-g-C 3 N 4 nanosheets depended strongly on the precursors of bulk g-C 3 N 4 samples. The well-developed Cu nanoparticles with clear lattice fringes were observed in the sample prepared using MCN (sample Cu-MCN) while the crystallinity of Cu nanoparticles became worse in the sample prepared using DCN (sample Cu-DCN). Interestingly, Cu clusters were homogeneously distributed in superior thin g-C 3 N 4 nanosheets in the case of using TCN (sample Cu-TCN) because of S components in thiourea affected the thermal polymerization. The photocatalytic activity of Cu-TCN was drastically improved compared with other Cu-g-C 3 N 4 samples. The photocatalytic hydrogen production rate of Cu-TCN with 1% of Cu components was 4035.6 μmol g-1 h-1. Cycle stability test indicated that sample Cu-TCN revealed high stability, in which the H 2 generation rate was retained 95% of their initial value after 5 cycles. These results supply efficient approaches for the study and application of g-C 3 N 4 based photocatalysts. • Cu components introduced in g-C 3 N 4 nanosheets using bulk g-C 3 N 4 created by different precursors. • Precursors (melamine, dicyandiamide, and thiourea) affect the activity of Cu-g-C 3 N 4 nanosheets. • Cu distribution in g-C 3 N 4 nanosheets depended on the thermal polymerization of precursors. • Cu clusters distributed in g-C 3 N 4 nanosheets created using thiourea revealed the best performance. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) carried out from electrocatalysis of water splitting is playing a major role in the production of green and clean hydrogen. In this paper, we report on the synthesis of graphitic carbon nitride on nickel hydroxide (g-C 3 N 4 /Ni(OH) 2) nanocomposites by a simple ultrasonication method. The characterizations include the XRD, Raman, FESEM and electrochemical studies to analyze the performance of the as developed material over hydrogen evolution reaction. The morphological analysis shows that the aggregated interconnected g-C 3 N 4 /Ni(OH) 2 (GCN/NH) nanocomposites with an average particle size of ∼20 nm. These GCN/NH nanocomposites exhibit the lowest overpotential of 341 mV at 10 mA/cm2 which is smaller than that of the pristine Ni(OH) 2 nanosheets at 367 mV. Further, the Tafel slope for GCN/NH nanocomposites reveals a lower value of 131 mV/dec. As a result, g-C 3 N 4 decorated sheet-like β-Ni(OH) 2 exhibits the potential hydrogen evolution in alkaline KOH solution. Excitingly, the as developed hybrid β-Ni(OH) 2 nanocomposites show superior electrocatalytic behaviour during the hydrogen evolution reaction and also improve the catalytic stability than pure nanosheets. From these observations, one can say that this g-C 3 N 4 /Ni(OH) 2 nanocomposite electrocatalyst can play a splendid role in future energy technology. • One step synthesis of β-Ni(OH) 2 and g-C 3 N 4 /Ni(OH) 2 via sonochemical method. • Prepared electrodes were characterized for the electrocatalytic HER studies. • The electrochemically active surface area of nanocomposite is higher than that of the pristine. • The overpotential of the g-C 3 N 4 /Ni(OH) 2 nanocomposite is lower than that of the pristine Ni(OH) 2. [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]

Two dimensional (2D)/2D heterostructures with much interface is advantage to improve the transfer of photogenerated carriers. In this paper, SnS 2 nanosheets were horizontally grown on superior thin graphic carbon nitride (g-C 3 N 4) nanosheets to construct 2D/2D heterostructures with enhanced photocatalytic performance. The g-C 3 N 4 nanosheets (CN) were obtained by a two-step thermal polymerization at 600 and 700 °C. the growth of SnS 2 nanosheets was then carried out using a solvothermal synthesis. Preparation parameters including temperature, reaction time, and precursor components were tested to get optimized SnS 2 /g-C 3 N 4 composite sample 8SnS 2 -CN. A Z-scheme mechanism was proposed for the discussion of photocatalytic process. The degradation test of Rhodamine B (Rh B) indicated that the degradation rate of Rh B using sample 8SnS 2 -CN was twice quick compared with g-C 3 N 4 nanosheets, in which Rh B degradation was completed within 15 min. The photocatalytic hydrogen production rate of sample 8SnS 2 -CN was about 6 times that that of sample CN, which is 1818.75 μmol g−1 L−1. Enhanced photocatalytic performance is ascribed to SnS 2 deposited to form well-developed interface which improved the separation and transfer of photogenerated carriers. In addition, the growth of SnS 2 was also expended the photo adsorption. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a visible light-driven polymeric carbon nitride (PCN)/(Pt)/nano-spherical MoS 2 photocatalysts was prepared using a self-assembly method. The structure of photocatalysts was explored by FT-IR, XPS, XRD, BET, SEM and TEM. Meanwhile, the energy band structure and electron hole separation efficiency were also analyzed by UV–Vis and PL spectra. In addition, the photocatalytic performance of photocatalysts were tested by photocatalytic degradation of Rhodamine B and photocatalytic hydrogen evolution. The results showed that PCN/2.0%MoS 2 showed the best photocatalytic performance, and the degradation rate of Rhodamine B could reach 98.39% within 150 min. Besides, the introduction of Pt nanoparticles significantly improved the photocatalytic activity. The degradation rate of Rhodamine B reached 100% within 150 min, and the rate of photocatalytic hydrogen production of PCN/Pt/MoS 2 system was increased by 21.3% over the PCN/2.0%MoS 2 system. The separation mechanism of electron and hole is Z-scheme mechanism and the main active substances for photocatalytic degradation were · O 2 − and h+. [Display omitted] • The catalyst is prepared by self-assembly. • Pt promotes the formation of carriers. • The transportation of carriers is Z-scheme. [ABSTRACT FROM AUTHOR]

• The recent advances of graphitic carbon nitride for the hydrogen production and photocatalytic water splitting were summarized. • The drawbacks and the solution to overcome it have been discussed. • The advanced strategies to increase the performance of graphitic carbon nitride have been systematically discussed. The future energy crisis and environmental degradation can only mitigate by harvesting solar energy into renewable, safe, economical and clean technology like water splitting. The graphitic carbon nitride has an attractive band structure, good chemical stability, earth-abundant and significantly easily fabricated which makes an application for the generation of hydrogen by water splitting. In this paper, we try to critically focus on the current progress and future development of the different strategies of water splitting using graphitic carbon nitride (g-C 3 N 4) for hydrogen generation. In this context, we discuss recent strategies like metal and non-metal doping (electronic structure), morphology tuning (geometric structuring), use of mediators (Z-scheme technology), defects engineering, plasmonic materials, dye-sensitization, perovskite oxides, carbon nitrides, carbon dots, metal organic framework, and a bimetallic cocatalyst. Finally, we summarize the recent advances and future developments of g-C 3 N 4 bases photocatalysis. [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]