Topics in Current Chemistry (2018) 376:41
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In another study, CoCu catalysts showed a high C 2 selectivity with a Co content between 5 and 15% [61]. An intermediate species change from CHO to COH
may help the C–C bond formation. A stronger CO binding on Co could also assist
CO–CO dimerization. Both contribute to the enhanced C 2 product formation (C 2 H 4 ,
C 2 H 5 OH).
Ma et al. showed that phase-separated Cu–Pd catalysts could reach as high as
50% FE for C 2 H 4 [47]. Ordered, disordered, and phase separated Cu–Pd catalysts
were synthesized (Fig. 5a). Major products were CO, CH 4 , C 2 H 4 , and C 2 H 5 OH. The
CO 2 reduction results of the Cu–Pd catalyst are shown in Fig. 5b–e. From all the
samples tested, Cu NPs and phase separated CuPd showed strongest and weakest
binding with CO based on the surface valence band photoemission spectra. However, both showed similar activity. Therefore, the authors determined that the geometric arrangement was more important than the electronic effect, with the orientation of the intermediate on the surface playing a key role for enhanced ethylene
formation. Another related work also showed both high ethylene FE and activity on
Cu can be achieved by optimizing the flow electrolyzer system [62].
From a theoretical point of view, tuning the binding energies of *COOH, *OH,
*COH and *CHO is the key to improving C 2+ selectivity [10]. Bell et al. designed
an AgCu alloy system to give a compressive strain of Cu [49]. CO 2 reduction was
conducted using 0.05 M Cs 2 CO 3 aqueous solution. After reaction, surfaces of AgCu
with 20–60% Cu bulk composition all changed to a more Cu-rich Ag 40 Cu 60 surface
due to the stronger interaction of CO with Cu than Ag. Comparing to a bulk Cu
electrode under the same reaction conditions, more than a 10% total enhancement
Fig. 5 a Illustration of prepared ordered, disordered and phase separated CuPd nanoalloys. FEs for b CO;
c CH 4 ; d C 2 H 4 ; e C 2 H 5 OH for CuPd nanoalloy catalyst in CO 2 RR. Reproduced with permission from
Ref. [47]
Reprinted from the journal
114
1 3
In another study, CoCu catalysts showed a high C 2 selectivity with a Co content between 5 and 15% [61]. An intermediate species change from CHO to COH
may help the C–C bond formation. A stronger CO binding on Co could also assist
CO–CO dimerization. Both contribute to the enhanced C 2 product formation (C 2 H 4 ,
C 2 H 5 OH).
Ma et al. showed that phase-separated Cu–Pd catalysts could reach as high as
50% FE for C 2 H 4 [47]. Ordered, disordered, and phase separated Cu–Pd catalysts
were synthesized (Fig. 5a). Major products were CO, CH 4 , C 2 H 4 , and C 2 H 5 OH. The
CO 2 reduction results of the Cu–Pd catalyst are shown in Fig. 5b–e. From all the
samples tested, Cu NPs and phase separated CuPd showed strongest and weakest
binding with CO based on the surface valence band photoemission spectra. However, both showed similar activity. Therefore, the authors determined that the geometric arrangement was more important than the electronic effect, with the orientation of the intermediate on the surface playing a key role for enhanced ethylene
formation. Another related work also showed both high ethylene FE and activity on
Cu can be achieved by optimizing the flow electrolyzer system [62].
From a theoretical point of view, tuning the binding energies of *COOH, *OH,
*COH and *CHO is the key to improving C 2+ selectivity [10]. Bell et al. designed
an AgCu alloy system to give a compressive strain of Cu [49]. CO 2 reduction was
conducted using 0.05 M Cs 2 CO 3 aqueous solution. After reaction, surfaces of AgCu
with 20–60% Cu bulk composition all changed to a more Cu-rich Ag 40 Cu 60 surface
due to the stronger interaction of CO with Cu than Ag. Comparing to a bulk Cu
electrode under the same reaction conditions, more than a 10% total enhancement
Fig. 5 a Illustration of prepared ordered, disordered and phase separated CuPd nanoalloys. FEs for b CO;
c CH 4 ; d C 2 H 4 ; e C 2 H 5 OH for CuPd nanoalloy catalyst in CO 2 RR. Reproduced with permission from
Ref. [47]
Reprinted from the journal
114