PHOTOELECTROCATALYTIC CONVERSION OF CO2 AND BIOGAS INTO PRODUCTS OF ENERGY INTEREST USING Ti/TiO2 NANOSTRUCTURED SEMICONDUCTORS MODIFIED WITH COPPER

This work describes the superficial modification of Ti/TiO2 nanotubes by copper oxide electrochemical deposition, in different temperatures (25 and 65 ºC), and its application on the photoelectrocatalytic conversion of CO2 and biogas in products of energy interest. The different temperatures deposition resulted in the formation of different geometric forms on the surface of Ti/TiO2 nanotubes and in different photoelectrocatalytic activities. The photoelectrocatalytic conversion in 0.1 mol L-1 Na2SO4 with application of -0.1 V and UV irradiation resulted in the formation of acetone and methanol from CO2 and acetone and ethanol from biogas, being that the acetone production was higher for the semiconductor synthesized at 65 ºC, while the methanol and ethanol production was higher for the semiconductor at 25 ºC. The different characteristics observed, as well as the preferential formation of different products of photoelectrocatalytic reactions for semiconductors synthesized with different electrochemical deposition temperatures are discussed.本研究阐述了采用氧化铜电化学沉积法对钛/二氧化钛（Ti/TiO₂）纳米管进行表面改性的过程，实验分别在25℃与65℃两种温度下开展，并将所得改性材料应用于CO₂与沼气的光电催化转化，以制备具备能源应用价值的产物。不同沉积温度会在钛/二氧化钛纳米管表面形成各异的几何形貌，同时赋予其差异化的光电催化活性。在施加-0.1V偏压、紫外辐照的0.1mol·L⁻¹硫酸钠（Na₂SO₄）电解液体系中进行光电催化转化时，CO₂可被转化为丙酮与甲醇，沼气则可被转化为丙酮与乙醇；其中，65℃下合成的半导体材料丙酮产率更高，而25℃合成的样品甲醇与乙醇产率更具优势。本研究针对观测到的材料特性差异，以及不同电化学沉积温度下合成的半导体材料所呈现的光电催化反应产物偏好性展开了讨论。