Ren Haizhou, Kan Zhe, Wang Zibo, Shen Mengyan
Department of Physics and Applied Physics, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854, United States.
Nanomanufacturing Center, University of Massachusetts Lowell, One University Avenue, Lowell, Massachusetts 01854, United States.
ACS Omega. 2020 Dec 7;5(51):33083-33089. doi: 10.1021/acsomega.0c04693. eCollection 2020 Dec 29.
Carbon dioxide (CO) and water (HO) have been converted into hydrocarbons at temperature ranging from 58 to 242 °C through an artificial photosynthesis reaction catalyzed by nanostructured Co/CoO. The experimental results show that chain hydrocarbons (alkane hydrocarbons) (C H, where 3 ≤ ≤ 16) mainly form at a temperature higher than about 60 °C, the production rate reaches a maximum at 130 °C, and abruptly decreases above 130 °C, and then gradually increases until 220 °C. While the temperature is higher than 220 °C, benzene (CH) and its derivatives such as toluene (CH), -xylene (CH), and CH form. The modeling of temperature dependence of the reaction rate reveals that the vaporization of the adsorbed water contributes to the sharp peak; the activation energy is estimated as about 1 eV, which is in agreement with the reaction of CO and H to synthesize chain hydrocarbons. The experimental results support the mechanism that the chemisorbed CO and physisorbed HO on the CoO surface are disassociated or excited with light, and the disassociated or excited molecules then synthesize hydrocarbons. When most of the water molecules leave from the CoO at temperature higher than 220 °C, the hydrogen source is of very low concentration while the carbon source remain the same because of the chemisorption, and thus benzene and its derivatives with low hydrogen atom number form.
通过纳米结构的Co/CoO催化的人工光合作用反应，二氧化碳（CO₂）和水（H₂O）在58至242°C的温度范围内被转化为碳氢化合物。实验结果表明，链状碳氢化合物（烷烃）（CₙH₂ₙ₊₂，其中3≤n≤16）主要在高于约60°C的温度下形成，产率在130°C时达到最大值，并在130°C以上急剧下降，然后逐渐增加直至220°C。当温度高于220°C时，苯（C₆H₆）及其衍生物如甲苯（C₇H₈）、对二甲苯（C₈H₁₀）和间二甲苯（C₈H₁₀）形成。反应速率的温度依赖性建模表明，吸附水的汽化导致了尖锐的峰值；活化能估计约为1eV，这与CO和H₂合成链状碳氢化合物的反应一致。实验结果支持了这样一种机制，即CoO表面化学吸附的CO和物理吸附的H₂O在光照下发生解离或激发，然后解离或激发的分子合成碳氢化合物。当温度高于220°C时，大多数水分子从CoO上离开，由于化学吸附，氢源浓度非常低而碳源保持不变，因此形成了氢原子数低的苯及其衍生物。
