Table 3.

Overview of recent developments in the reduction of CO₂ to multicarbon alcohols between 2018 and 2021

FE	Current densities [mA cm−2]	Potential vs RHE [V]	Catalyst	Electrolyte	Membrane	Ref
H-type cells
52.3% EtOH	<15 total	−0.3	Au@Cu2O yolkshell NPs on carbon cloth	0.1 M KHCO3	PEM (Nafion 117)	(Zhang et al., 2020a)
80% C2 products	21C2 products	−1.09	Reconstructed porous Cu	0.1 M KHCO3	PEM (Nafion 117)	(Han et al., 2020b)
33.7% EtOH 6.9% PrOH	8.67 EtOH 1.8 PrOH	−1 −0.9	Ag15Cu85	0.5 M KHCO3	–	(Dutta et al., 2020)
64.6% EtOH 8.7% PrOH	ca. 8 EtOH ca. 1.2 PrOH	−1.05	Cu NPC	0.2 M KHCO3	PEM (Nafion 212)	(Han et al., 2020a)
≈80% C2+ products	ca. 8C2+ products	−0.9	CuOx	0.1 M CsHCO3	AEM (Selemion AMV)	(Jeong et al., 2020)
ca. 70% C2+ products	40 to 50C2+ products	−1.05	Cu oxide-/hydroxide-derived	0.1 M KHCO3	PEM (Nafion 117)	(Lei et al., 2020)
78% EtOH	ca. 0.2 EtOH	−0.56	Micropores in N-doped mesoporous carbon	0.1 M KHCO3	PEM	(Song et al., 2020)
16.4% EtOH 14.9% C2H4	4.1 EtOH	−1.1	Cu-OD + Ag (20 nm)	0.1 M KHCO3	AEM (Selemion AMV)	(Ting et al., 2020)
80% C2+ products with 40% C2H4, (EtOH, PrOH)	ca. 4 total	−1.2	Cu NPs + poly-aniline	0.1 M KHCO3	AEM (QAPPT)	(Wei et al., 2020)
48% EtOH	2.5 total	−0.8	Cobalt corrole complex on carbon paper	0.1 M NaClO4	–	(Gonglach et al., 2019)
25% C2H4 5% EtOH	–	−1.8	Cu(OH)2/Cu	0.1 M NaHCO3	PEM (Nafion)	(Iijima et al., 2019)
21% C2H4 29% EtOH	18 total	−1.0	Cu@Cu2O	0.1 M KHCO3	–	(Shang et al., 2019)
69% C2+ products	45.5C2+ products	−1.0	CuOx	0.1 M CsHCO3 +0.1 M CsI	AEM (Selemion AMV)	(Gao et al., 2018)
60% C2+ products (32% C2H4)	68 total 40C2+ products	−0.96	Cu-NCs	0.25 M KHCO3	PEM (Nafion 117)	(Jiang et al., 2018b)
79.1–85.2% EtOH	0.31 total	−0.5 to −0.7	Ag-graphene-NCF	0.1 M KHCO3	AEM	(Lv et al., 2018b)
79% C2 products (52% C2H4 27% EtOH)	10C2 products	−1.1	Boron-doped Cu	0.1 M KHCO3	PEM (Nafion 117)	(Zhou et al., 2018)
40.3% C2H4 16.7% EtOH 12.1% n-PrOH 4.4% AcOH	20 to 30 total	−1.3	CuPb-0.7/C	0.1 M KHCO3	PEM (Nafion 117)	(Wang et al., 2020a)
72% C2+ products (35.9% EtOH)	8.75 EtOH	−1.25	Dodecanethiol-modified CuBr	0.5 M KCl	PEM (Nafion 117)	(Wang et al., 2021)
13.7% n-PrOH	1.15 PrOH	−0.65	PdCu alloy foam (Pd9Cu91)	0.5 M KHCO3	PEM (Nafion 117)	(Rahaman et al., 2020)
20.2% EtOH 2.1% PrOH 33.6% C2H4	–	−1.1	OD-Cu90Zn10 cubes	0.1 M KHCO3	AEM (AHO, AGC Inc.)	(da Silva et al., 2020)
32% EtOH	<10 total	−1.1	Multimetallic CuAgHg	0.1 M KHCO3	–	(Kim et al., 2020b)
53% EtOH 18% n-PrOH	30 to 35 total	−1.08	Defect-site rich Cu	0.1 M KHCO3	–	(Gu et al., 2021)
Flow cells
78% C2+ products (C2H4 49%)	466C2+ products	−0.73	ZnO-layer on top of Cu on carbon paper	1 M KOH	–	(Zhang et al., 2020c)
85.5% C2-4 (15% EtOH; 65.2% C2H4)	800 total	−0.89	Fluorine-modified Cu	1 M KOH	AEM	(Ma et al., 2020c)
52% EtOH	156 EtOH	−0.68	Cu + N-C on PTFE substrate	1 M KOH	AEM	(Wang et al., 2020b)
41% EtOH	124 EtOH	−0.82	FeTTP[Cl] on Cu, sputtered on PTFE substrate	1 M KHCO3	AEM (Fumapem FEE-3-PK-130)	(Li et al., 2020)
75.2% C2+ products	267C2+ products	−0.61	Multi-hollow Cu oxide	2 M KOH	AEM	(Yang et al., 2020b)
36.9% alcohols 8.6% MeOH 28.3% EtOH	20 total	−0.67	Cu + Bibased metal-organic frameworks (MOFs)	0.5 M KHCO3	PEM (Nafion 117)	(Albo et al., 2019)
55% EtOH	16.2 total	−1.2	Cu-N-C	0.1 M CsHCO3	AEM (Selemion AMV)	(Karapinar et al., 2019)
41% EtOH	250 total	−0.67	Ag0.14/Cu0.86	1 M KOH	AEM (Fumasep FAA-3-PK-130)	(Li et al., 2019)
61.7% C2+ products 42% C2H4 14% EtOH 5% PrOH	185C2+ products	−0.59	Cu-Cu4O3	2.5 M KOH	PEM (Nafion 117)	(Martić et al., 2019)
48.6% C2+ products	97C2+ products	−0.68	ZnO/CuO	1 M KOH	AEM	(Ren et al., 2019)
40% C2 products (C2H4, EtOH)	234 total	−1.17	CuxO	2 M KOH	PEM	(Xiang et al., 2019)
60% C2H4 25% EtOH	180C2H4	−0.7	Cu-Ag	1 M KOH	AEM (Fumatech FAP-375-PP)	(Hoang et al., 2018)
84% C2+ products (>60% C2H4)	336C2+ products	−0.68	CuCl-derived Cu	3 M KOH	AEM	(Kibria et al., 2018)
62% C2+ products (C2H4, EtOH PrOH)	411C2+ products	−0.67	Cu-NPs	1 M KOH	AEM (FAA-3 Fumatech)	(Lv et al., 2018a)
32% C2+-alcohols (25% EtOH 7% PrOH)	120C2+ alcohols	−0.92	Cu2S-Cu-V	1 M KOH	AEM	(Zhuang et al., 2018)
29.9% EtOH 1.43% n-PrOH 16.3% AcOH	400 total	Min. −1.5	CuPb-0.7/C	1 M KOH	AEM (Fumasep FAB-PK-130)	(Wang, P. et al., 2020)
64% C2+ products (15% EtOH)	210 total	−0.7 to −0.75	P-doped Cu (Cu0.92P0.08)	1 M KOH	PEM (Nafion 115)	(Kong et al., 2021)
52.4% C2+ alcohols	282.1 total	−0.9	N-doped graphene quantum dots on Cu-OD Cu-nanorods	1 M KOH	AEM (Fumasep FAA-3-PK-130)	(Chen et al., 2020a)
<30% EtOH	400 total	–	Ag2Cu2O3	1 M CsHCO3	AEM (Fumasep FAB-PK-130)	(Martić et al., 2020)
40% C2H4 20% EtOH	–	−0.5	Cu electrodeposited on carbon paper	1 M KOH	AEM (Fumatech)	(Hoang et al., 2017)
52% EtOH 15% n-PrOH	100 total	−0.95	Defect-site rich Cu	1 M KOH	AEM	(Gu et al., 2021)