Enhanced Photocatalytic Performance toward CO2 Hydrogenation over Nanosized TiO2-Loaded Pd under UV Irradiation

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• 作者：Naixu Li ; Ming Liu ; Bin Yang ; Weixin Shu ; Quanhao Shen ; Maochang Liu ; Jiancheng Zhou
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：121
• 期：5
• 页码：2923-2932
• 全文大小：706K
• ISSN：1932-7455

文摘

A series of Pd/TiO₂ photocatalysts were synthesized by a simple glucose reduction method, and their photocatalysis properties were evaluated in an array of CO₂ hydrogenations. The samples were characterized by XRD, SEM, TEM, EDX, EDX mapping, UV–vis DRS, Raman spectroscopy, PL spectroscopy, XPS, and N₂ adsorption. In terms of product yields (in micromoles per gram of catalyst), a 1.0 wt % Pd/TiO₂ catalyst (CH₄, 355.62; CO, 46.35; C₂H₆, 39.69) was found to be superior to pristine TiO₂ (CH₄, 42.65; CO, 4.73; C₂H₆, 2.7) and other composites under UV irradiation for 3 h, possibly because of a synergistic effect between the palladium nanoparticles and the TiO₂ support. The palladium nanoparticles on the surface of TiO₂ substantially accelerated electron transfer and acted as active sites for the adsorption and activation of CO₂ molecules, to promote CO₂ hydrogenation. During the photocatalytic CO₂ hydrogenation, dissociated hydrogen reacts with CO₂^– activated on the Pd/TiO₂ photocatalyst to form a new Pd—C surface species that is stable during the reaction and further transforms to generate methane. A detailed mechanism of photocatalytic CO₂ hydrogenation is discussed to account for the performance of the Pd/TiO₂ photocatalyst in the reaction.