In-situ spectroscopic probe of the intrinsic structure feature of single-atom center in electrochemical CO/CO2 reduction to methanol

Abstract

While exploring the process of CO/CO2 electroreduction (COxRR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of COxRR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm2 in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO2 to methanol is strongly decreased in CO2RR. In-situ X-ray absorption and Fourier-transform infrared spectroscopies point to a different adsorption configuration of *CO intermediate in CORR as compared to that in CO2RR, with a weaker stretching vibration of the C–O bond in the former case. Theoretical calculations further evidence the low energy barrier for the formation of a H-CoPc-CO– species, which is a critical factor in promoting the electrochemical reduction of CO to methanol.

Modulating Electronic Structure Engineering of Atomically Dispersed Cobalt Catalyst in Fenton-like Reaction for Efficient Degradation of Organic Pollutants

“…Based on the different molecules (CoPc and CoPc-NH 2 ), the as-obtained catalysts were denoted as CoPc/G and CoPc/G-NH 2 , respectively. CoPc/G-NH 2 was prepared using our previously reported method. , Briefly, 100 mg of graphene was dispersed in 100 mL of N , N -dimethylformamide (DMF), forming a uniform solution under ultrasonication for 1 h. Then 10 mg of CoPc-NH 2 was added to the above solution with ultrasonic treatment for another 30 min. After that, the mixture was stirred for 48 h at room temperature.…”

Electrochemical CO2 Reduction to Methanol by Cobalt Phthalocyanine: Quantifying CO2 and CO Binding Strengths and Their Influence on Methanol Production

“…This result is quantitatively consistent with similar studies by Liu and co-workers conducted in a non-flow aqueous H-cell. 31 We interpret this result to mean that the partial pressure of CO must be sufficiently high relative to CO 2 for CO to bind to the catalyst and react to form CH 3 OH. In comparison, when CO 2 was substituted with N 2 , CH 3 OH forms at a much lower P CO of 0.02 atm (Figure 1a)�N 2 does not competitively inhibit CH 3 OH, whereas CO 2 does.…”

“…Multiple reports demonstrate CORR performance with 20−90 mA/cm 2 j CH3OH and >65% FE CH3OH in zero-gap flow electrolyzers. 30,31 The contrast in CH 3 OH production by CoPc under the CO 2 RR and CORR conditions suggests that CO-to-CH 3 OH is largely suppressed by the presence of CO 2 . The suppression is closely related to the relative binding strength of CO and CO 2 to CoPc.…”

“…The suppression is closely related to the relative binding strength of CO and CO 2 to CoPc. 31 In more recent studies, Wang and co-workers pointed out that the bound CO species (*CO) is labile on CoPc sites and high *CO concentration in the microenvironment is necessary to compete with CO 2 in order to facilitate CH 3 OH formation. 32 However, a gap in the literature is a quantitative understanding of CO and CO 2 binding and how the difference in binding influences the formation of CH 3 OH on CoPc.…”

Electrocatalysis with molecules and molecular assemblies within gas diffusion electrodes

“…There is, however, much work to be done in developing more effective molecular CO reduction catalysts since there are not many studies doing this with GDEbased systems. Photochemical and electrochemical studies have previously shown that methane and methanol can be produced from CO. [112][113][114] Success here would further enable molecular CO reduction catalysts to be combined with technologies like high-temperature electrolysis of CO 2 to CO, which also do not have issues of carbonate formation. Beyond this, molecular active sites can be used for CO 2 xation beyond the simple CO 2 R such as the generation of products with C-N bonds (e.g.…”