Generation of Hydrogen and Oxygen from Water by Solar Energy Conversion

Abstract

Photosynthesis is considered to be one of the promising areas of cheap and environmentally friendly energy. Photosynthesis involves the process of water oxidation with the formation of molecular oxygen and hydrogen as byproducts. The aim of the present article is to review the energy (light) phase of photosynthesis based on the published X-ray studies of photosystems I and II (PS-I and PS-II). Using modern ideas about semiconductors and biological semiconductor structures, the mechanisms of H+, O2↑, e− generation from water are described. At the initial stage, PS II produces hydrogen peroxide from water as a result of the photoenzymatic reaction, which is oxidized in the active center of PS-II on the Mn4CaO5 cluster to form O2↑, H+, e−. Mn4+ is reduced to Mn2+ and then oxidized to Mn4+ with the transfer of reducing the equivalents of PS-I. The electrons formed are transported to PS-I (P 700), where the electrochemical reaction of water decomposition takes place in a two-electrode electrolysis system with the formation of gaseous oxygen and hydrogen. The proposed functioning mechanisms of PS-I and PS-II can be used in the development of environmentally friendly technologies for the production of molecular hydrogen.

Electro-enzymatic processes in mitochondria

“…SDH-B subunit contains three iron-sulfur clusters: [Fe2-S2], [Fe4-S4] and [Fe3-S4], which act as electron carriers from succinate to ubiquinone. The clusters' chain is located in 40 Å across the entire enzyme molecule [7].…”

Productive and Sustainable H2 Production from Waste Aluminum Using Copper Oxides-Based Graphene Nanocatalysts: A Techno-Economic Analysis

“…Although the current processing methods commonly use fossil fuels, there are sustainable methodologies suggesting high-potential H 2 storage systems, such as water, biomass, and hydrated metals, which are still at the research stage and require more investigation and manipulation [3][4][5][6][7][8][9]. Water-splitting, based on solar systems, using photocatalysts for H 2 production is widely investigated in the literature [10][11][12][13][14]. However, such approaches are still economically unfeasible and are prone to reversible reactions [12][13][14].…”

“…Water-splitting, based on solar systems, using photocatalysts for H 2 production is widely investigated in the literature [10][11][12][13][14]. However, such approaches are still economically unfeasible and are prone to reversible reactions [12][13][14]. Therefore, efforts are being directed toward other sustainable technologies for efficient production.…”