A green route is developed to prepare hierarchical porous carbon sheets (HPCS) from biomass directly under air atmosphere without inert gas protection. The as-prepared HPCS with ultra-thin structure, rich O doping sites and large SSA demonstrate excellent specific capacitance and stability when used in supercapacitor.

Hierarchical ZnO composed of ultrathin nanosheets as secondary structures were fabricated through a hydrothermal method. Afterwards, hexagonal wurtzite CdS with diameter between 50-100 nm were incorporated on the wurtzite ZnO sheets with the assistance of ultrasonic irradiation. The hybrid ZnO/ CdS samples were intensively investigated by SEM, TEM, HRTEM, XRD, XPS, PL and the UV-Vis absorption spectrum. The photocatalytic trials confirmed that the ZnO/CdS hierarchical heterostructures exhibit improved degradation efficiency compared to pure ZnO sample under natural sunlight. CdS nanoparticles are believed to serve as photo-sensitizers to extend the absorption spectrum to the visible region and the loading amount was also found to play a crucial role in influencing the degradation efficiency. Moreover, the photodegradation kinetics of RhB via using CdS/ZnO as photocatalysts were also systematically discussed. Finally, a mechanism based on this band-gap alignment was proposed to elucidate the efficiency enhancement of the hybrid photocatalysts.

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Activated N-doped porous carbons (a-NCs) were synthesized by pyrolysis and alkali activation of graphene incorporated melamine formaldehyde resin (MF). The moderate N doping levels, mesopores rich porous texture, and incorporation of graphene enable the applications of a-NCs in surface and conductivity dependent electrode materials for supercapacitor and dye-sensitized solar cell (DSSC). Under optimal activation temperature of 700 °C, the afforded sample, labeled as a-NC700, possesses a specific surface area of 1302 m2 g(-1), a N fraction of 4.5%, and a modest graphitization. When used as a supercapacitor electrode, a-NC700 offers a high specific capacitance of 296 F g(-1) at a current density of 1 A g(-1), an acceptable rate capability, and a high cycling stability in 1 M H2SO4 electrolyte. As a result, a-NC700 supercapacitor delivers energy densities of 5.0-3.5 Wh kg(-1) under power densities of 83-1609 W kg(-1). Moreover, a-NC700 also demonstrates high electrocatalytic activity for I3- reduction. When employed as a counter electrode (CE) of DSSC, a power conversion efficiency (PCE) of 6.9% is achieved, which is comparable to that of the Pt CE based counterpart (7.1%). The excellent capacitive and photovoltaic performances highlight the potential of a-NCs in sustainable energy devices.