Center for Renewable Energy Science & Technology, University of Texas at Arlington, Arlington, TX 76019, USA.
Chemphyschem. 2013 Jul 22;14(10):2251-9. doi: 10.1002/cphc.201300080. Epub 2013 May 24.
Solar photoelectrochemical reduction of carbon dioxide to methanol in aqueous media was driven on hybrid CuO/Cu2O semiconductor nanorod arrays for the first time. A two-step synthesis was designed and demonstrated for the preparation of these hybrid copper oxide one-dimensional nanostructures on copper substrates. The first step consisted in the growth of CuO nanorods by thermal oxidation of a copper foil at 400 °C. In the second step, controlled electrodeposition of p-type Cu2O crystallites on the CuO walls was performed. The resulting nanorod morphology with controllable wall thickness by adjusting the Cu2O electrodeposition time as well as their surface/bulk chemical composition were probed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. Photoelectrosynthesis of methanol from carbon dioxide was demonstrated at -0.2 V vs SHE under simulated AM1.5 solar irradiation on optimized hybrid CuO/Cu2O nanorod electrodes and without assistance of any homogeneous catalyst (such as pyridine or imidazole) in the electrolyte. The hybrid composition, ensuring double pathway for photoelectron injection to CO2, along with high surface area were found to be crucial for efficient performance in methanol generation under solar illumination. Methanol formation, tracked by gas chromatography/mass spectrometry, indicated Faradaic efficiencies of ~95%.
首次在水相介质中用光电化学还原二氧化碳合成甲醇，采用的是混合氧化铜/氧化亚铜半导体纳米棒阵列作为催化剂。本文设计并展示了一种两步合成法，在铜基底上制备这种混合氧化铜一维纳米结构。第一步是在 400°C 下通过铜箔的热氧化生长 CuO 纳米棒。第二步，通过控制电化学沉积在 CuO 壁上生长 p 型 Cu2O 晶须。通过扫描电子显微镜、X 射线衍射和拉曼光谱研究了纳米棒形貌，通过调节 Cu2O 电沉积时间可控制纳米棒壁的厚度，还研究了其表面/体化学组成。在优化后的混合 CuO/Cu2O 纳米棒电极上，在模拟 AM1.5 太阳光照下，于 -0.2 V vs SHE 进行二氧化碳光电合成甲醇，电解液中没有任何均相催化剂（如吡啶或咪唑）的辅助。研究发现，混合组成确保了光电子向 CO2 注入的双路径，以及高表面积，这对于在太阳光照下高效生成甲醇非常重要。通过气相色谱/质谱跟踪甲醇的形成，表明法拉第效率约为 95%。
