Modulating H2O Activity Promotes CO2 Reduction to Multi-Carbon Products

电化学——由风能或太阳能产生的可持续或可再生电能驱动——为可持续的循环碳经济提供了一条道路，从而减少了我们对化石燃料的依赖，减轻了气候变化的影响。为此，该项目侧重于将主要温室气体二氧化碳转化为增值化学品和燃料。该项目的新颖之处在于了解了水在电化学反应中的作用，这种电化学反应可以有效地、有选择地将二氧化碳转化为多碳烃化学物质，这些化学物质可以作为燃料、塑料、涂料和建筑产品等多种产品的基本原料。通过改变溶液中盐的浓度，可以改变水（H2O）的化学活性，从而有可能更好地控制CO2与H2O的反应，从而产生所需的多碳产物。除了技术方面，该项目还提供STEM领域的教育和培训机会，特别关注社会经济弱势学生。该项目研究了水在调节电催化二氧化碳还原反应（CO2RR）中的作用，以有利于高效和选择性地形成C2+产物。研究者实验室的初步数据表明，降低水活度有利于多碳产物的生成。通过将水中的盐浓度调整在0.1到10mol / l的范围内，研究人员成功地改变了溶液中水的活度，这反过来又提高了C2产物的产量，而不是C1产物。为了理解在降低水活度的情况下改善二氧化碳电化学还原为C2或C2+产物的原因，将进行三个具体的项目推进，即：1)通过同时改变铜电极上改进的二氧化碳到多碳燃料的阳离子、阴离子和水活度来优化溶液组成；2)利用表面增强原位红外吸收光谱（SEIRAS）研究电解质结构在调节催化中的作用；3)探索利用电解液工程促进cu合金催化剂上CO2还原为多碳醇。该项目更广泛的教育和推广方面将向社会经济上处于不利地位的学生介绍可再生能源研究的概念。具体而言，研究者将与一名博士后助理和一名本科生一起参加约翰霍普金斯大学的工程创新计划（EIP）。学生将进行直接的实践实验，以熟悉基本的可再生能源概念，目的是激发他们对STEM领域的兴趣，这些领域与支持温室气体减排和减轻环境影响的教育和职业道路相关。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Electrochemistry – driven by sustainable or renewable electrical energy generated by wind or solar energy – offers a path toward a sustainable, circular carbon economy, thereby reducing our reliance on fossil fuels and mitigating the impacts of climate change. To that end, the project focuses on transforming carbon dioxide (CO2), a major greenhouse gas, into value-added chemicals and fuels. The novelty of the project lies in understanding the role of water in the electrochemical reactions that convert CO2 efficiently and selectively to multi-carbon hydrocarbon chemicals for use as building-blocks for a broad range of products including fuels, plastics, coatings, and construction products. By varying the concentration of salt in a solution, the chemical activity of water (H2O) can be altered, potentially enabling greater control over the reaction of CO2 with H2O to produce the desired multi-carbon products. Beyond the technical aspects, the project offers educational and training opportunities in STEM areas, especially focused on socioeconomically disadvantaged students. The project investigates the role of H2O in modulating the electrocatalytic CO2 reduction reaction (CO2RR) to favor efficient and selective formation of C2+ products. Preliminary data from the investigator’s laboratory has shown that lowering the water activity favors the generation of multi-carbon products. By adjusting the salt concentrations within a range of 0.1 to 10 molal in the water the investigators have successfully altered the activity of water in the solution, which, in turn, enhances the production of C2 products over their C1 counterparts. Three specific project thrusts will be pursued to understand the origin of improved electrochemical reduction of CO2 to C2 or C2+ products with decreased water activity, namely: 1) optimize solution composition by simultaneously varying the cation, anion, and water activity for improved CO2-to-multicarbon fuels on Cu electrodes, 2) interrogate the role of the electrolyte structure in modulating catalysis with surface-enhanced in-situ infrared absorption spectroscopy (SEIRAS); and 3) explore electrolyte engineering to boost CO2 reduction to multi-carbon alcohols on Cu-alloy catalysts. Broader educational and outreach aspects of the project will introduce socioeconomically disadvantaged students to concepts of renewable energy research. Specifically, the investigator, along with a post-doctoral associate and undergraduate student, will participate in the Engineering Innovation Program (EIP) at Johns Hopkins University. Students will conduct straightforward hands-on experiments to acquaint them with fundamental renewable energy concepts, with the goal of piquing their interest in STEM areas as related to educational and career paths supporting greenhouse gas reduction and mitigation of environmental impacts.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.