• Energy Research
• 2016-2025close

Graphitic carbon Nitride (g-C3N4) is one of the most utilized graphitic materials in hydrogen (H2) production via photocatalytic water splitting. Thus, a detailed critical overview, updated with the most recent works, has been performed on the synthesis methods, modification techniques, characterization, and mechanisms of g-C3N4 and g-C3N4-based composite materials, with the aim of clarifying the optimum course towards highly efficient hydrogen-producing photocatalysts based on this promising material. First, the synthesis methods for different morphologies of pure g-C3N4 (bulk, nanosheets, nanotubes and nanodots) are critically analyzed in detail for every step and parameter involved, with special mention regarding the modification methods of g-C3N4 (doping and composite formation). Next, the most common results of g-C3N4 characterization, regarding structural, morphological, optical, and electrical properties, are presented and analyzed. Then, a detailed critical survey of the mechanisms, using g-C3N4 and g-C3N4-based composites during photocatalytic activity, is performed with a focus on their effect on their hydrogen production capabilities via water splitting. This review aims to provide a clear image of all aspects regarding the use of g-C3N4 for photocatalysis, as well as a comprehensive guide for research targeted towards this promising graphitic material.

Nowadays, water pumping systems based on photovoltaics as a source of electricity have widely increased. System cost and efficiency still require enhancement in order to spread their application. Perovskite solar cells (PSCs) are the most hopeful third-generation photovoltaic for replacing the silicon-based photovoltaic thanks to their high power conversion efficiency, reaching 25.8%; tunable band-gap; long diffusion length; low fabrication temperature; and low cost. In this work, for the first time, we proposed a high-power-density hybrid perovskite solar cell thermoelectric generator (TEG) array for feeding a synchronous reluctance motor (SynRM) driving a water pump for use in an irrigation system. A control technique was used to achieve two functions. The first function was driving the motor to obtain the maximum torque/ampere. The second was harvesting the maximum perovskite solar cell array output power on the basis of the maximum power point tracking (MPPT) algorithm using the perturbation and observation approach. Thus, the proposed hybrid perovskite solar cell–thermoelectric generator feeds the motor via an inverter without DC–DC converters or batteries. Accordingly, the short life problems and the high replacement cost are avoided. The proposed complete system was simulated via the MATLAB package. Moreover, a complete laboratory infrastructure was constructed for testing the proposed high-power-density hybrid perovskite solar cell–TEG array for the water pumping system. The results revealed that using the high-power-density hybrid perovskite solar cell–TEG array, both the motor’s output power and the pump’s flow rate were improved by 11% and 14%, respectively, compared to only using the perovskite solar cell array. Finally, both the simulation and experimental results proved the high-performance efficiency of the system in addition to showing its system complexity and cost reduction.

In this paper, after illustrating the current state of the art, we present our own technology in manufacturing super-paramagnetic nanoparticles (SPAN). The method is based on chemical coprecipitation by using single ion precursors, like chloride or/and nitrate salts. Apart from synthetic route description, a demonstration ofthe methods used for structural analysis and electric-magnetic properties determination is done followed by the comments and remarks on the recorded results. Finally, the role of doping in magnetic and optical properties of the prepared nanomagnetic materials is illustrated and the potential utilization of these materials in various technological applications is presented.