Pulsing strategies to control reactivity and selectivity in photochemistry

创造一个可持续发展的社会需要我们停止使用化石碳来生产化学品和燃料，以停止增加大气中的二氧化碳（CO2）水平。另一种方法是不简单地将二氧化碳作为废物处理，而是将其用作化学合成的碳中性原料。以这种方式回收二氧化碳是一项挑战，因为它的转化需要大量的能量投入，并且可以产生许多不同的产品，通常是不受欢迎的混合物。通过将可再生电力作为能源和催化剂材料相结合，以帮助刺激所需的反应途径，电化学方法是一种有前途的CO2转化新兴技术。但是，当在恒定的操作条件下操作电化学装置时，基本的挑战仍然存在，包括限制反应效率和速率的大的能量势垒和有害的浓度梯度。我们提出了一种基于电化学CO2转化反应的脉冲激活的策略，由脉冲光的输入刺激，这可以提供用于最小化反应障碍和微调反应途径的策略。通过结合光吸收半导体和有机或无机催化剂，我们将研究混合装置上的脉冲光光电化学，其目标是获得对CO2转化机制的新理解，展示改进的产品选择性，并建立共振催化的新前沿。

Creating a sustainable society requires that we stop using fossil-based carbon to produce chemicals and fuels, in order to stop increasing atmospheric levels of carbon dioxide (CO2). An alternative is to treat CO2 not simply as waste, but instead use it as a carbon-neutral feedstock for chemical synthesis. Recycling of CO2 in this way is a challenge because its transformation requires significant energy input and many different products can be produced, usually as an undesirable mixture. By combining renewable electricity as energy source and catalyst materials to help stimulate the desired reaction pathways, the electrochemistry approach is a promising emerging technology for CO2 conversion. But fundamental challenges persist when operating electrochemical devices under constant operating conditions, including large energy barriers and detrimental concentration gradients which limit the reaction efficiency and rate. We propose a strategy based on pulsed activation of electrochemical CO2 conversion reactions, stimulated by the input of pulsed light, which can provide strategies for minimizing reaction barriers and fine-tuning the reaction pathways. By combining light-absorbing semiconductors and organic or inorganic catalysts, we will study pulsed light photoelectrochemistry on hybrid devices with the goals of gaining new understanding of CO2 conversion mechanisms, demonstrating improved product selectivities, and establishing a new frontier in resonance catalysis.