Tin–nickel catalyst turns simulated flue gas into fuel gas
A laboratory system combined carbon capture with electrolysis to produce about 1,500 litres of fuel gas from simulated flue gas in roughly five days. Tiny tin–nickel clusters helped suppress unwanted multicarbon products. The peer-reviewed work yielded a mixture of methane, carbon monoxide and hydrogen; its pure-carbon-dioxide performance measurements describe separate experimental conditions.
Science··Morning
Carbon capture feeds directly into electrolysis
Researchers in China and Canada combined a carbon-capture solution with an electrolytic cell to turn dilute carbon dioxide into fuel gas. Their tin–nickel catalyst limited the multicarbon products that complicate separation in many copper-based systems. In a controlled experiment using simulated flue gas, the integrated setup collected about 1,500 litres of syngas in roughly five days. The product contained methane, carbon monoxide and hydrogen.[1], [2]
The simulated inlet contained 15 percent carbon dioxide, 81 percent nitrogen and 4 percent oxygen. A potassium carbonate solution absorbed the carbon dioxide, producing bicarbonate-rich liquid for direct electrolysis. This linked capture and conversion without first supplying the cell with a separate stream of purified carbon dioxide. Residual carbon dioxide was absorbed again during gas collection.[1], [2]
Tiny clusters favour methane formation
Computational screening compared 33 surface models before experiments refined the catalyst. The resulting tin–nickel clusters measured about 0.7–0.8 nanometres and sat on a nickel–nitrogen–carbon support. Synchrotron X-ray measurements examined their atomic arrangement during operation. Calculations indicated that the clusters changed interactions with a carbon-containing intermediate, favouring a reaction step needed to form methane.[1], [2]
Tests with pure carbon dioxide separated two performance measures. In a small two-compartment cell, about 81 percent of the electric charge went into methane production. A different flow-cell experiment reached a methane partial current density of 1,024 milliamperes per square centimetre, with 50 percent selectivity at that setting. The highest efficiency and highest current therefore came from different operating points.[1], [2]
Long runs used distinct gas feeds
With pure carbon dioxide, a durability run lasted more than 600 hours, maintaining methane selectivity between 72 percent and 75 percent. The five-day simulated-flue-gas demonstration used a larger cell with an active area of 100 square centimetres. Its collected gas had a methane-to-carbon-monoxide-to-hydrogen volume ratio of about three to four to three. Carbon monoxide was the largest component.[1], [2]
The experiments link catalyst design to liquid handling and gas collection, with additional tests in a 240-square-centimetre flow cell. The simulated gas contained no dust, sulfur oxides or nitrogen oxides. Operation with actual factory exhaust, together with a full accounting of electricity use and costs, remains necessary before the system’s industrial or emissions-reduction performance can be established.[1], [2]
