Direct air capture of CO for solar fuel production in flow.

Direct air capture is an emerging technology to decrease atmospheric CO levels, but it is currently costly and the long-term consequences of CO storage are uncertain. An alternative approach is to utilize atmospheric CO on-site to produce value-added renewable fuels, but current CO utilization technologies predominantly require a concentrated CO 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) through on-site utilization of air-captured CO using light without requiring high temperature or pressure. The reactor consists of a bed of solid silica-amine adsorbent to capture aerobic CO and produce CO-free air; concentrated light is used to release the captured CO 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 is captured during night-time and converted to syngas under concentrated sunlight during the day.