Abstract

Three types of composite photocatalysts synthesized by the sol-gel method and doped with sulfur and nitrogen were considered. The factors influencing the structure formation and properties of active sites on the catalysts based on hybrid nickel-titanium oxide systems promoted by sulfur and nitrogen in the production of hydrogen from water were studied. The conditions of preparation were established to have an essential effect on the physicochemical and catalytic properties of the synthesized materials. The introduction of NiO into the structure of TiO₂ was demonstrated to increase its photocatalytic activity in the production of hydrogen from a methanol–water mixture. Doping with nitrogen and sulfur also improved the catalytic activity of the synthesized catalysts. The mechanism of charge transfer in the photocatalytic Ti(IV)–O–Ni(II) system under visible light irradiation was revealed. The existence of so-called p–n junctions in these complex oxide systems was shown, and the limits of their application were determined. The dependence between the number of photocatalytic sites and their activity in the destruction reaction of water-soluble organic compounds was revealed. This process was controlled by such factors as the concentration of organic compounds, the catalyst amount, and pH of the reaction medium. The optimal concentration of a catalyst in the studied systems was estimated as 1 g/dm³. The highest hydrogen formation rate was observed at pH ~ 7 close to the pH value at the zero charge point of the titanium dioxide surface. A new approach to the synthesis of photocatalysts was proposed, thus opening up additional opportunities in the development of heterostructures for the photocatalytic conversion of solar energy and the production of hydrogen fuel.

中文翻译：

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S，N掺杂半导体NiO-TiO 2氧化物上水的光催化分解

摘要

考虑了三种通过溶胶-凝胶法合成并掺杂有硫和氮的复合光催化剂。研究了在水制氢过程中，硫和氮促进的镍-钛杂化混合体系催化剂上活性位的结构形成和性能的影响因素。确定了制备条件，以对合成材料的物理化学和催化性能产生重要影响。NiO在TiO ₂结构中的引入被证明可以提高其在甲醇-水混合物制氢过程中的光催化活性。氮和硫的掺杂也改善了合成催化剂的催化活性。揭示了可见光照射下光催化Ti（IV）–O–Ni（II）系统中电荷转移的机理。所谓p – n的存在显示了这些复杂氧化物系统中的结，并确定了其应用范围。揭示了在水溶性有机化合物的破坏反应中光催化部位的数目及其活性之间的依赖性。该过程由诸如有机化合物的浓度，催化剂量和反应介质的pH等因素控制。在研究的系统中催化剂的最佳浓度估计为1 g / dm ³。在接近二氧化钛表面零电荷点的pH值的pH〜7处观察到最高的氢形成速率。提出了一种合成光催化剂的新方法，从而为开发用于太阳能光催化转化和生产氢燃料的异质结构开辟了更多的机会。