Scanning electrochemical microscopy (SECM) feedback mode has been used to investigate regeneration kinetics on P1 (4-(bis-{4-[5-(2,2-dicyanovinyl) thiophene-2-yl] pH-enyl} amino) benzoic acid) dye sensitized nickel oxide (NiO) electrodes in contact with reduced iodide liquid electrolyte in different electrolyte solvents. We were used acetonitrile, ethanol, methanol and propylene carbonate solvents for comparison under illumination of different wavelengths. We found significant variation of regeneration kinetics parameters such as regeneration rate constant (k eff ), the reduction rate constant (k red ) and absorption cross-section (Φhv) in different illumination intensity and different solvents.

The objective of the study is to provide scientific information of the solar potential of Afar region, for photovoltaic (PV) solar energy industry sectors. The afar region being exceptional solar potential with high average solar radiation flux 239.9W/m 2 (105.4% of average photon energy surface area of Ethiopia), and average annual solar density of 2.102MW•h/m 2 (105.5% of the average yearly solar density of Ethiopia). This finding requests the photovoltaic system as an alternative principal energy resource to substitute the present energy system in afar region. These comprehensive indication of the solar energy marketplace in Afar region, Ethiopia, key visions into its governing framework, energy sector, of photovoltaic (PV) industry segments. Therefore, the photovoltaic energy system has the best opportunity for basic energy application in the pastoral community for daily life consumption, such as solar lighting, for solar cooker, small devices and for air conditioning. These studies show that the Afar region gifted with significantly high monthly average daily solar radiation as a potential candidate for development of PV energy systems in Afar region. Therefore, the PV system has the power to run an evaporative air conditioning system effectively. These findings indicate that photovoltaic energy system as most promising energy in the Afar region.

The world’s most urgent problem today is the quick depletion of energy resources, which necessitates research into alternative energy sources in order to meet the world’s explosive growth in energy demand. Among other renewable energy sources, biodiesel holds promise for meeting energy demand at a low cost through a variety of processes. In the biodiesel industry, sophisticated catalysts have recently grown in popularity for their ability to activate esterification and transesterification processes. The goal of this chapter is to give a general overview of catalyst developments, including their benefits and drawbacks in the biodiesel production process. In particular, we present a comparison of various homogeneous and heterogeneous catalysts. We found that nanocatalysts hold the most promise for the production of biodiesel.

Recently, the world energy demand has been raised up dramatically. Numerous energy sources have been developed to satisfy the urgent energy desires and to overcome the world energy crisis. Among them, solar energy has been considered an efficient energy source for current energy requirements. Nowadays, the lead-based perovskite solar cells achieved excellent power conversion efficiency exceeding 29.1%. However, to address major problems such as toxicity and underprivileged stability, several hardworks were made toward the replacement of lead-free perovskite material in perspective of device’s performance and stability. In this book chapter, we summarize material, dimensions, stability, and the current achievement of lead-free solar cells. Finally, we review the remaining challenges and future perspective for development of lead-free perovskite solar cells.