Abstract Photocatalysis has been a topic of interest in recent years for both, oxidation and reduction reactions, and although there is a broad variety of research regarding photocatalytic materials and the reaction itself, studies on reactor design and related phenomena, radiation transfer and its direct impact on reaction extent specifically, are usually neglected. From this end, the present work focuses on the elucidation of the effect of light intensity and wavelength spectra in the visible light region during the photoreduction reaction of formic acid using graphene oxide as a promising catalyst. By using formic acid, one of the main intermediaries in the photoreduction of carbon dioxide, the possibility of methanol production is evaluated without the thermodynamic constraints presented by carbon dioxide. A graphene oxide material, synthetized through a modified Hummer’s method, is assessed for the reduction of formic acid evaluating four different light sources (red, green, blue and white). An analysis of energy balances in the reaction set-up allows the determination of both the energy absorbed by the GO photocatalyst and isoactinity conditions at studied radiative operating conditions. At an isoactinity environment, the adsorption rate of formic acid and production rate of methanol are then evaluated, relating them to the absorbed energy achieved at the wavelength spectra and light intensities evaluated; IR spectroscopy is utilized to follow formic acid concentration as well as methanol production. The largest initial reaction rate (ca. 57%) relates to the use of the red wavelength at its largest intensity. Reaction rates at larger times start to be apparent being affected by adsorption, reaction and radiation conditions. The maximum conversion, 14%, is attained by using the white wavelength spectra at its lowest intensity. Thus, higher intensities will not necessarily yield higher conversions, nor the highest reaction rates. This, in turn, poses the necessity of quick, reliable assessments for whichever catalyst used in this type of reactions that leads to the correct election of operating conditions that maximize the product yield. Independent evaluation for every wavelength within the visible spectra and assessing carbon dioxide photoreduction are future steps into the elucidation of solar fuel production feasibility.

中文翻译：

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使用氧化石墨烯材料评估光强度和光波长光谱对甲酸光还原的影响

摘要 近年来，光催化一直是氧化和还原反应的热点话题，尽管对光催化材料和反应本身进行了广泛的研究，但对反应器设计和相关现象、辐射转移及其直接影响的研究具体就反应程度而言，通常被忽略。为此，目前的工作重点是阐明在使用氧化石墨烯作为有前景的催化剂的甲酸光还原反应过程中可见光区的光强度和波长光谱的影响。通过使用甲酸（二氧化碳光还原的主要中间体之一），可以在没有二氧化碳所呈现的热力学约束的情况下评估甲醇生产的可能性。一种氧化石墨烯材料，通过改进的 Hummer 方法合成的甲酸通过评估四种不同的光源（红色、绿色、蓝色和白色）进行评估。反应装置中能量平衡的分析允许在研究的辐射操作条件下确定 GO 光催化剂吸收的能量和等光度条件。在等光度环境下，然后评估甲酸的吸附速率和甲醇的生产速率，将它们与在评估的波长光谱和光强度下获得的吸收能量相关联；红外光谱用于跟踪甲酸浓度以及甲醇生产。最大的初始反应速率 (ca. 57%) 与在其最大强度下使用红色波长有关。较大时间的反应速率开始明显受到吸附、反应和辐射条件的影响。最大转化率为 14%，是通过使用最低强度的白色波长光谱获得的。因此，较高的强度不一定会产生较高的转化率，也不一定会产生最高的反应速率。这反过来又要求对此类反应中使用的任何催化剂进行快速、可靠的评估，以正确选择操作条件，从而最大限度地提高产品收率。对可见光谱内每个波长的独立评估和评估二氧化碳光还原是阐明太阳能燃料生产可行性的未来步骤。是通过使用其最低强度的白色波长光谱来实现的。因此，较高的强度不一定会产生较高的转化率，也不一定会产生最高的反应速率。这反过来又要求对此类反应中使用的任何催化剂进行快速、可靠的评估，以正确选择操作条件，从而最大限度地提高产品收率。对可见光谱内每个波长的独立评估和评估二氧化碳光还原是阐明太阳能燃料生产可行性的未来步骤。是通过使用其最低强度的白色波长光谱来实现的。因此，较高的强度不一定会产生较高的转化率，也不一定会产生最高的反应速率。这反过来又要求对此类反应中使用的任何催化剂进行快速、可靠的评估，以正确选择操作条件，从而最大限度地提高产品收率。对可见光谱内每个波长的独立评估和评估二氧化碳光还原是阐明太阳能燃料生产可行性的未来步骤。对此类反应中使用的任何催化剂进行可靠评估，以正确选择操作条件，从而最大限度地提高产品产量。对可见光谱内每个波长的独立评估和评估二氧化碳光还原是阐明太阳能燃料生产可行性的未来步骤。对此类反应中使用的任何催化剂进行可靠评估，以正确选择操作条件，从而最大限度地提高产品产量。对可见光谱内每个波长的独立评估和评估二氧化碳光还原是阐明太阳能燃料生产可行性的未来步骤。