Center of Excellence for Nanostructured Materials (CENMAT) and INSTM, unit of Trieste, Dipartimento di Scienze Chimiche e Farmaceutiche, University of Trieste, Piazzale Europa 1, I-34127 Trieste, Italy.
ACS Nano. 2013 Jan 22;7(1):811-7. doi: 10.1021/nn305313q. Epub 2012 Dec 27.
The artificial leaf project calls for new materials enabling multielectron catalysis with minimal overpotential, high turnover frequency, and long-term stability. Is graphene a better material than carbon nanotubes to enhance water oxidation catalysis for energy applications? Here we show that functionalized graphene with a tailored distribution of polycationic, quaternized, ammonium pendants provides an sp(2) carbon nanoplatform to anchor a totally inorganic tetraruthenate catalyst, mimicking the oxygen evolving center of natural PSII. The resulting hybrid material displays oxygen evolution at overpotential as low as 300 mV at neutral pH with negligible loss of performance after 4 h testing. This multilayer electroactive asset enhances the turnover frequency by 1 order of magnitude with respect to the isolated catalyst, and provides a definite up-grade of the carbon nanotube material, with a similar surface functionalization. Our innovation is based on a noninvasive, synthetic protocol for graphene functionalization that goes beyond the ill-defined oxidation-reduction methods, allowing a definite control of the surface properties.
人工叶片项目需要新的材料，以实现具有最小过电势、高转化频率和长期稳定性的多电子催化。在增强用于能源应用的水氧化催化方面，石墨烯是否比碳纳米管更好？在这里，我们展示了具有聚阳离子、季铵化铵侧链的功能化石墨烯，它提供了一个 sp(2) 碳纳米平台，用于锚定完全无机的四钌酸盐催化剂，模拟天然 PSII 的氧气产生中心。所得的混合材料在中性 pH 下的过电势低至 300 mV 即可进行氧气释放，经过 4 小时测试后，性能几乎没有损失。与孤立的催化剂相比，这种多层电活性资产将转化频率提高了 1 个数量级，并对具有类似表面功能化的碳纳米管材料进行了明确的升级。我们的创新基于一种非侵入性的、用于石墨烯功能化的合成方案，该方案超越了定义不清的氧化还原方法，能够对表面特性进行明确的控制。
