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<p>Electrode materials were prepared from activated carbonizates of walnut shell, apricot pits and shungite rock from “Bakyrchik” deposit, East Kazakhstan. Physicochemical characteristics of the obtained samples were studied by the Brunauer-Emett-Taylor method, scanning electron microscopy, Raman spectroscopy and other methods. Electrochemical properties of the obtained materials were studied by the method of cyclic voltammetry. It was found that the samples have an amorphous structure. Samples based on plant raw materials after hydrothermal carbonization at 240 °С during 24 h, have more homogeneous and developed surface. Specific surface area of carbon containing materials based on apricot pits is 1300 m²/g, for those on the based on mineral raw material, it is 153 m²/g. It was shown that materials after hydrothermal carbonization can be used for catalytic purposes and electrodes after thermal carbonization for analytical and electrocatalytic purposes. Electrode obtained by HTC have electrocatalytic activity. CSC 240 has high background current (slope i/Е is 43 mА V^–1 cm^–2), low potential of the hydrogen electroreduction (more positive by ~ 0.5 V than samples based on plant raw materials). The reaction of DA determination is more pronounced on the electrodes obtained by HTC 240 °C, 24 h, due to the nature, carbon structure and high specific surface area of obtained samples.</p>

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.

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