We have developed a facile, scale up, and efficient method for the preparation of graphitic-C3N4 nanofibers (GCNNFs) as electrodes for supercapacitors and photocatalysts. The as-synthesized GCNNFs have 1D structure with higher concentration of nitrogen that is favorable for higher conductivity and electrochemical performance. Secondly, the high surface area of GCNNF provides a large electrode-electrolyte contact area, sufficient light harvesting and mass transfer, as well as increased redox potential. Thus, the GCNNF supercapacitor electrode shows high capacitance of 263.75 F g(-1) and excellent cyclic stability in 0.1 M Na2SO4 aqueous electrolyte with the capacitance retention of 93.6% after 2000 cycles at 1 A g(-1) current density. GCNNFs exhibit high capacitance of 208 F g(-1) even at 10 A g(-1), with the appreciable capacitance retention of 89.5%, which proves its better rate capability. Moreover, the GCNNF shows enhanced photocatalytic activity in the photodegradation of RhB in comparison to the bulk graphitic-C3N4 (GCN). The degradation rate constant of GCNNF photocatalyst is almost 4 times higher than GCN. The enhanced photocatalytic activity of GCNNF is mainly due to the higher surface area, appropriate bandgap, and fewer defects in GCNNF as compared to GCN. As an economical precursor (melamine) and harmless, facile, and template-free synthesis method with excellent performance both in supercapacitors and in photodegradation, GCNNF is a strong candidate for energy storage and environment protection applications.

We have established a facile and scaleable approach to fabricate tubular graphitic-C3N4 using melamine. The construction of the unique tubular morphology is a result of the pre-treatment of melamine with HNO3. Herein, for the first time, we have explored the electrochemical properties of g-C3N4 as an electrode material for supercapacitors. Tubular g-C3N4 has significant advantages due to its distinctive morphology, high surface area (182.61 m 2 g -1 ) and combination of carbon with nitrogen. Therefore, tubular g-C3N4 demonstrated a good specific capacitance of 233 F g -1 at a current density of 0.2 A g -1 in 6 M KOH electrolyte. Furthermore, tubular g-C3N4 maintained a high capacitance retention capability (90%) after 1000 cycles. The photocatalytic activity of tubular g-C3N4 was evaluated using the organic dyes such as Methylene Blue (MB) and Methylene Orange (MO) under visible light. Tubular g-C3N4 demonstrated good photocatalytic activity and enhanced stability compared to bulk g-C 3N4. The enhanced performance is because of the high surface area, which contains more active sites for reaction. The encouraging performance of tubular g-C3N4 in supercapacitors and as a photocatalyst points toward it being a prospective material for energy storage that is environmentally clean. The Royal Society of Chemistry. We have established a facile and scaleable approach to fabricate tubular graphitic-C 3 N 4 using melamine.The construction of the unique tubular morphology is a result of the pre-treatment of melamine with points toward it being a prospective material for energy storage that is environmentally clean.

The electrocatalytic oxygen evolution reaction (OER) plays a critical role in sustainable energy conversion and storage, but OER is severely hampered owing to the lack of highly efficient catalysts. Here, we report an efficient electrocatalyst, with NiO/Co 3 O 4 nanoparticles decorated on nitrogen-doped carbon (NiO/Co 3 O 4 @ NC). Abundant high-valence Ni 3+ and Co 3+ species were observed on the surface of the hybrid due to the strong NC−metal oxide and NiO−Co 3 O 4 interactions. This unique structure leads to excellent OER performance, delivering a very low overpotential of 240 mV@10 mA•cm −2 on glassy carbon and 200 mV@10 mA•cm −2 on Ni foam in KOH and having a turnover frequency (@350 mV overpotential) 6 and 16 times higher than that of IrO 2 and RuO 2 , respectively.

Well controlled nanosheets-based hierarchical microspheres (NSHMS) of pure covellite phase CuS were synthesized using a facile PVP assisted solvothermal process. The reaction conditions were optimized using various amounts of PVP to develop unique hierarchical structured hollow microspheres. CuS hollow structures have a bandgap of ~1.97 eV. These mesoporous structures exhibit excellent photocatalytic activity in degradation of organic dyes (Methylene Blue) under natural light in comparison to other structures of copper sulphide. These photocatalysts show extraordinary reusability with over 96.5% degradation of organic dye after 6th cycle. A "bottom-up" assembly was successfully developed to synthesize hollow microspheres with unique and well defined architectures at large scale, which offer a good opportunity to understand the fundamental significance of unusual and complex hierarchical structures for their potential applications. This journal is the Partner Organisations 2014.Keywords nanosheet, light, driven, cus, free, synthesis, hierarchical, photocatalyst, template, microspheres, efficient, natural Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsTanveer, M., Cao, C., Ali, Z., Aslam, I., Idrees, F., Khan, W. S., But, F. K., Tahir, M. & Mahmood, N. (2014 Well controlled nanosheets-based hierarchical microspheres (NSHMS) of pure covellite phase CuS were synthesized using a facile PVP assisted solvothermal process. The reaction conditions were optimized using various amounts of PVP to develop unique hierarchical structured hollow microspheres. CuS hollow structures have a bandgap of~1.97 eV. These mesoporous structures exhibit excellent photocatalytic activity in degradation of organic dyes (Methylene Blue) under natural light in comparison to other structures of copper sulphide. These photocatalysts show extraordinary reusability with over 96.5% degradation of organic dye after 6th cycle. A "bottom-up" assembly was successfully developed to synthesize hollow microspheres with unique and well defined architectures at large scale, which offer a good opportunity to understand the fundamental significance of unusual and complex hierarchical structures for their potential applications.

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An easy, scalable and environmentally benign chemical method has been developed to synthesize micro strings of graphitic-C3N4 (msg-C3N4) through pre-treatment of melamine with HNO 3 in alkaline solvent at low temperature. This methodology results in a unique string type morphology of msg-C3N4 with higher surface area. These msg-C3N4 micro strings were used as a photocatalyst under visible light for photodegradation of rhodamine B, methyl blue and methyl orange. The msg-C3N4 shows enhanced photodegradation efficiency due to its high surface area and favourable bandgap. The first order rate constant for msg-C3N4 was measured which confirms the higher performance of msg-C3N4 in comparison to other reported materials such as g-C3N4, Fe2O3/g-C3N4 and TiO2 nanotubes. Thus, the method developed here is favourable for the synthesis of materials with higher surface area and unique morphology, which are favourable for high photodegradation activity. The Royal Society of Chemistry. Keywordsscale, large, c, inf, 3, production, novel, g, n, 4, ability, micro, strings, photodegradation, versatile, area, surface, high Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsTahir, M., Cao, C., Butt, F. K., Butt, S., Idrees, F., Ali, Z., Aslam, I., Tanveer, M., Mahmood, A. & Mahmood, N. (2014). Large scale production of novel g-C3N4 micro strings with high surface area and versatile photodegradation ability. CrystEngComm, 16 (9), 1825-1830. AuthorsMuhammad Nawaz Tahir An easy, scalable and environmentally benign chemical method has been developed to synthesize micro strings of graphitic-C 3 N 4 (msg-C 3 N 4 ) through pre-treatment of melamine with HNO 3 in alkaline solvent at low temperature. This methodology results in a unique string type morphology of msg-C 3 N 4 with higher surface area. These msg-C 3 N 4 micro strings were used as a photocatalyst under visible light for photodegradation of rhodamine B, methyl blue and methyl orange. The msg-C 3 N 4 shows enhanced photodegradation efficiency due to its high surface area and favourable bandgap. The first order rate constant for msg-C 3 N 4 was measured which confirms the higher performance of msg-C 3 N 4 in comparison to other reported materials such as g-C 3 N 4 , Fe 2 O 3 /g-C 3 N 4 and TiO 2 nanotubes. Thus, the method developed here is favourable for the synthesis of materials with higher surface area and unique morphology, which are favourable for high photodegradation activity.

Hierarchical nanostructures (Hs) have recently garnered enormous attention due to their remarkable performances in catalysis, electronic devices, energy storage and conversion. Considering the advantage of hierarchical nanostructures, we have formulated a facile and template free method to synthesize novel hierarchical nanospheres (NHNs) of ZnV2O4. Both zinc and vanadium are earth abundant, relatively economical and can offer several oxidation states, which can render a broad range of redox reactions favorable for electrochemical energy storage applications. Keeping these points in mind, we investigated for the first time the electrochemical supercapacitor performance of NHNs. The electrochemical measurements were performed in 2 M KOH solution. The measured specific capacitance of ZnV2O4 electrode is 360 F/g at 1 A/g with good stability and retention capacity of 89% after 1000 cycles. Moreover, the hydrogen storage properties of NHNs were measured at 473, 573, and 623 K with an absorption of 1.76, 2.03, and 2.49 wt %. respectively. These studies pave the way to consider ZnV2O4 as prospective material for energy storage applications.

Catalysts for oxygen and hydrogen evolution reactions (OER/HER) are at the heart of renewable green energy sources such as water splitting. Although incredible efforts have been made to develop efficient catalysts for OER and HER, great challenges still remain in the development of bifunctional catalysts. Here, we report a novel hybrid of Co 3 O 4 embedded in tubular nanostructures of graphitic carbon nitride (GCN) and synthesized through a facile, large-scale chemical method at low temperature. Strong synergistic effects between Co 3 O 4 and GCN resulted in excellent performance as a bifunctional catalyst for OER and HER. The high surface area, unique tubular nanostructure, and composition of the hybrid made all redox sites easily available for catalysis and provided faster ionic and electronic conduction. The Co 3 O 4 @GCN tubular nanostructured (TNS) hybrid exhibited the lowest overpotential (0.12 V) and excellent current density (147 mA/cm 2 ) in OER, better than benchmarks IrO 2 and RuO 2 , and with superior durability in alkaline media. Furthermore, the Co 3 O 4 @GCN TNS hybrid demonstrated excellent performance in HER, with a much lower onset and overpotential, and a stable current density. It is expected that the Co 3 O 4 @GCN TNS hybrid developed in this study will be an attractive alternative to noble metals catalysts in large scale water splitting and fuel cells.