Multimetallic CO2 Reduction Catalysts as Artificial Cofactors

作为人工辅助因子的多金属二氧化碳还原催化剂

• 批准号: EP/Y002695/1
• 负责人: Alexander Kilpatrick
• 金额: $ 21.07万
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FY002695%2F1
• 关键词: Multimetallic; CO2; Reduction; Catalysts; Artificial

Carbon dioxide (CO2) levels on Earth have reached an all-time high, and mitigating man-made climate change is a defining challenge of our era. However the global economy and our society are critically dependent on fossil fuels, which meet 80% of the worlds energy demands and account for the production of 95% of all chemical commodities we rely on in our everyday lives. One example, ethylene, is a two-carbon molecule that is currently produced from fossil fuels in a highly energy-consuming and polluting petrochemical process. Ethylene is called a platform chemical as it used to synthesise a wide range of other chemicals, and is a crucial monomer in many common plastics. One emerging technology is to enable the direct conversion of CO2 emissions into carbon-based chemicals, thereby much reducing the environmental damage caused by their production. Nature uses this 'waste' gas as its primary one-carbon building-block for biomass, and the chemical industry is beginning to realise the potential of CO2 as a cheap, renewable feedstock for producing of vital chemicals such as ethylene. Conversion of CO2 is challenging as the molecule is very stable and unreactive, and a vast energy input is required to make it react. Catalysts are needed to lower this energy requirement and interest is growing in new transition metal catalysts for CO2 activation. The scalable industrial application of this technology is currently held back by poor catalyst efficiency and low selectivity for a particular carbon-containing product. Although catalysts have been developed to generate one-carbon products from CO2, there are very few examples in which multi-carbon (C2+) products are formed. This is a key barrier to be overcome: C2+ compounds like ethylene represent the best trade-off between high economic value and a reduction in global warming potential, if they could be produced from CO2 using renewable electrical energy. This is an opportunity with massive potential impact for decarbonising innovation at scale in the chemicals industry, since more ethylene is produced each year than any other organic compound, and its annual production releases around 200 million tons of CO2. Of the existing catalysts, none are sufficiently active or selective for C2+ products. This is partly due to a lack of fundamental understanding about the requirements for C-C bond forming; this theoretical underpinning is needed to make rational steps to design improved catalysts.To address these challenges, this research takes inspiration from enzyme catalysts which are able to reduce CO2 to C2+ hydrocarbons with good activity and selectivity - but cannot be scaled. The model enzymes are the carbon monoxide dehydrogenases for CO2 reduction to CO in Nature, and nitrogenases for reduction of nitrogen to ammonia. These enzymes harbour multiple transition metals in their active sites, positioned where coupling of two CO2 units can occur. In a collaboration initiated by recent discoveries in the researchers' laboratories, hybrid catalysts that combine the benefits of synthetic catalysts and enzymes will be developed. Their use in synthetic CO2 conversion will be tested, taking this principle of confined catalyst sites to promote C-C bond formations between multiple metal sites.Producing chemicals from CO2 requires an energy input, and energy must come from a decarbonised source to reduce emissions. Our catalysts will use electrons to drive the reaction, since renewable electrical energy is becoming increasingly available at low cost. Studying the reaction mechanisms 'on-the-fly' will inform the design of more efficient catalysts, with the ultimate aim of realising a catalytic method for converting CO2 into any carbon-containing molecule. Borrowing a trick or two from enzymes, this research will move the chemical industry a step closer to becoming part of a true, waste-free, circular economy, as well as helping to make the goal of generating negative CO2 emissions a reality.

地球上的二氧化碳（CO2）水平已达到历史最高水平，减缓人为气候变化是我们这个时代的一个决定性挑战。然而，全球经济和我们的社会严重依赖化石燃料，化石燃料满足了世界80%的能源需求，并生产了我们日常生活中依赖的所有化学商品的95%。例如，乙烯是一种双碳分子，目前是在高能耗和高污染的石化过程中从化石燃料中生产的。乙烯被称为平台化学品，因为它用于合成各种其他化学品，并且是许多常见塑料中的关键单体。一项新兴技术是将二氧化碳排放直接转化为碳基化学品，从而大大减少其生产对环境造成的破坏。大自然使用这种“废气”作为生物质的主要一碳组成部分，化学工业开始意识到二氧化碳作为生产乙烯等重要化学品的廉价可再生原料的潜力。二氧化碳的转化具有挑战性，因为该分子非常稳定且不反应，并且需要大量的能量输入才能使其反应。需要催化剂来降低这种能量需求，并且对用于CO2活化的新型过渡金属催化剂的兴趣正在增长。该技术的可规模化工业应用目前受到催化剂效率差和对特定含碳产物的选择性低的阻碍。尽管已经开发了催化剂以从CO2产生一碳产物，但是很少有形成多碳（C2+）产物的实例。这是一个需要克服的关键障碍：如果可以使用可再生电能从二氧化碳中生产乙烯等C2+化合物，那么它们代表了高经济价值和降低全球变暖潜力之间的最佳权衡。这是一个对化学工业大规模脱碳创新具有巨大潜在影响的机会，因为每年生产的乙烯比任何其他有机化合物都多，其年产量约为2亿吨二氧化碳。在现有的催化剂中，没有一种对C2+产物具有足够的活性或选择性。这在一定程度上是由于对C-C键形成的要求缺乏基本的理解;需要这种理论基础来制定合理的步骤来设计改进的催化剂。为了解决这些挑战，本研究从酶催化剂中汲取灵感，这些酶催化剂能够以良好的活性和选择性将CO2还原为C2+烃，但不能规模化。模型酶是自然界中用于将CO2还原成CO的一氧化碳还原酶和用于将氮还原成氨的固氮酶。这些酶在其活性位点中含有多种过渡金属，位于两个CO2单元可以发生偶联的位置。在由研究人员实验室最近发现发起的一项合作中，将开发出联合收割机，它结合了合成催化剂和酶的优点。将测试它们在合成CO2转化中的应用，利用限制催化剂位点的原理促进多个金属位点之间的C-C键形成。从CO2生产化学品需要能量输入，而能量必须来自脱碳源以减少排放。我们的催化剂将使用电子来驱动反应，因为可再生电能正变得越来越便宜。“实时”研究反应机理将为设计更有效的催化剂提供信息，最终目标是实现将CO2转化为任何含碳分子的催化方法。借用酶的一两个技巧，这项研究将使化学工业更接近成为真正的无废物循环经济的一部分，并有助于实现产生负二氧化碳排放的目标。