Abstract
Direct air capture is an emerging technology to decrease atmospheric CO(2) levels, but it is currently costly and the long-term consequences of CO(2) storage are uncertain. An alternative approach is to utilize atmospheric CO(2) on-site to produce value-added renewable fuels, but current CO(2) utilization technologies predominantly require a concentrated CO(2) feed or high temperature. Here we report a gas-phase dual-bed direct air carbon capture and utilization flow reactor that produces syngas (CO + H(2)) through on-site utilization of air-captured CO(2) using light without requiring high temperature or pressure. The reactor consists of a bed of solid silica-amine adsorbent to capture aerobic CO(2) and produce CO(2)-free air; concentrated light is used to release the captured CO(2) and convert it to syngas over a bed of a silica/alumina-titania-cobalt bis(terpyridine) molecular-semiconductor photocatalyst. We use the oxidation of depolymerized poly(ethylene terephthalate) plastics as the counter-reaction. We envision this technology to operate in a diurnal fashion where CO(2) is captured during night-time and converted to syngas under concentrated sunlight during the day.