Advancing in the photocatalyst scale-up is crucial for the development of highly efficient solar fuels production at industrial scale. Here, we report DC-magnetron sputtering as a suitable technique to produce photocatalytic TiO₂ coatings for CO₂ reduction with a view on process scalability. The crystallinity of the obtained TiO₂ coatings varies with surface density, with amorphous or quasi-amorphous coatings obtained with very low densities, while UV light absorption coefficients show the opposite trend, which has been related to the proportionally higher abundace of surface defects and grain boundaries associated to the small crystal size and/or amorphicity of the lightest coatings. The as-prepared samples lead to the reduction of CO₂ as demonstrated by ¹³C isotope tracing. An optimum catalyst area density of 1 g/m² (by geometric area) is obtained in terms of CO₂ photoreduction production, which is ascribed to a compromise situation between crystallinity and absorption coefficient. Selectivity to the different reaction products also varies with the coating characteristics, with amorphous or quasi-amorphous light coatings favouring methanol formation, in contrast with the preferred CO evolution in heavier, crystalline ones. Raman spectroscopy reveals the formation of peroxo and peroxocarbonate species on the photocatalyst surface as oxidation products during the CO₂ reduction, the accummulation of which is proposed to be related to the observed catalyst deactivation.

扩大光催化剂的规模对于发展工业规模的高效太阳能燃料生产至关重要。在这里，我们报告直流磁控溅射作为一种合适的技术来生产用于CO ₂还原的光催化性TiO ₂涂层，其方法具有工艺可扩展性。所获得的TiO ₂涂层的结晶度随表面密度而变化，所获得的非晶态或准非晶态涂层的密度非常低，而紫外线吸收系数却呈现相反的趋势，这与表面缺陷和晶粒的丰度成比例地增加有关。与最轻的涂层的小晶体尺寸和/或非晶性相关的边界。制备后的样品可减少CO ₂如¹³ C同位素示踪所示。就CO _2光还原产生而言，获得了最佳催化剂面积密度为1 g / m ²（按几何面积计），这归因于结晶度和吸收系数之间的折衷情况。与不同的反应产物的选择性也随涂层特性而变化，非晶态或准非晶态的轻质涂层有利于甲醇的形成，与重质结晶态中优选的CO放出相反。拉曼光谱揭示了在CO ₂期间光催化剂表面上过氧化物和过碳酸盐物种的形成是氧化产物。 还原，其积累被认为与观察到的催化剂失活有关。