In:
EES Catalysis, Royal Society of Chemistry (RSC), Vol. 1, No. 2 ( 2023), p. 117-124
Abstract:
Cu is a unique metal that catalyzes carbon monoxide/carbon dioxide (CO/CO 2 ) to form high-order hydrocarbons and oxygenates through the CO/CO 2 reduction reaction (CO/CO 2 RR) at decent selectivity and productivity. While this has been shown, the limits of the system are still unknown, i.e. , the minimum amount of Cu needed for the CO/CO 2 RR, and the maximum activity that trace amounts of Cu can achieve. Here, we have investigated the activity and selectivity of trace Cu with atomic dispersion over a range of loadings below 2 μg cm −2 and have quantified the mass activity/turnover frequency (TOF) of trace Cu catalysts. A Cu loading of at least 0.042 μg cm −2 initiates the CORR activity with 30% faradaic efficiency (FE) at a partial current density of 102 mA cm −2 forming predominantly CH 4 . The selectivity moves to C 2 -based products (CH 3 COO − , C 2 H 4 , and CH 3 CH 2 OH) with 70% FE as the Cu loading increases to 0.333 μg cm −2 , and increasing the Cu loading to 0.812 μg cm −2 results in a 78% FE to C 2 with CH 3 COO − accounting for 42% of this. The highest mass activity for CH 4 reaches 2435 A mg −1 of Cu, corresponding to a TOF of 267 s −1 , while C 2 activity reaches 584 A mg −1 of Cu, leading to a TOF of 145 s −1 . Both TOFs are several orders of magnitude higher than the reported values. Different from the CORR, the CO 2 RR demands a higher Cu loading and primarily generates C 1 ( e.g. , CO and CH 4 ). Metal impurities can be extended to others that are active towards the CO 2 RR, such as Zn for CO 2 -to-CO conversion. Thus, we suggest that the effect of trace metal impurities must be quantified when developing carbon-based metal-free and coordinated single-atom catalysts for the CO/CO 2 RR in order to avoid overestimating their activity.
Type of Medium:
Online Resource
ISSN:
2753-801X
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2023
detail.hit.zdb_id:
3146060-4
Bookmarklink
