Due to the increased environmental threat from CO2 emission, efficient and selective conversion of CO2 to useful chemicals and fuels has received considerable attention. Developing new nanocatalysts is an attractive solution. Of various catalysts explored to date, gold (Au) is the most promising one to convert CO2 to CO in an aqueous-phase electrochemical reduction. However, ultrasmall Au nanocatalysts (AuNCs, &lt; 2 nm) have proven to be more favorable for water reduction over CO2, although they possess a large surface-to-volume ratio providing abundant active sites. We report that ultrasmall AuNCs (1.9 ± 0.3 nm) supported on nitrided carbon showed remarkable activity and selectivity for CO2 reduction. At 0.7 V, the mass activity reaches &gt; 1000 A g-1 with a Faradaic efficiency for CO of ~80 %, that is an order of magnitude more active than the state-of-the-art results. The cooperative effect of Au and the nitride carbon support is essential for the high activity and selectivity of ultrasmall AuNCs. X-ray photoelectron spectroscopy (XPS) shows an electron rich surface of AuNCs on nitrided carbon, compared to the ones after quenching N sites. Thermogravimetric analysis/mass spectrometry (TGA-MS) confirms that the nitrided carbon has a stronger CO2 adsorption compared to the ones with quenched N sites. We expect that our results will illustrate an alternative way to effectively lower the cost of Au catalyst per unit weight of the product while maintaining the high selectivity for CO2 reduction.

Superiorly active and selective Au nanocatalysts supported on nitrided carbon for electrocatalytic CO2 reduction

256th National Meeting (2018)

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