Table 10.

Catalytic systems, major products, maximum FEs, and mechanisms of Pd and Pt complexes in electrochemical CO₂ reduction (n.a.=not available, prop.=proposal, comp.=computational investigation, exp.=experimental evidence).

Entry	Cat. system	Substitution	Major product	Max. FE (%)	Mechanism	Basis	Method	Ref.
1a		L=MeCN, PEt3, PPh3, P(CH2OH)3, P(OMe)3 R1=Et, neopentyl, Cy, Ph, (CH2)2PO(OEt)2, NMe2 R2=tBu, neopentyl, Ph, Mes, (CH2)3OH, TMB,[a] (CH2)2PMe3 +, (CH2)2PBu3 +, NMe2, NEt2, NiPr2, OMe	CO/H2O CH4 H2	94 [319] 11 [319] 90 [316]	ETH [320] ETM [316]	prop. exp.	n.a. CV	[316, 319–321]
1b		R=Et, Ph	CO/H2O H2	25 87	n.a.	n.a.	n.a.	[322]
1c		–	CO/H2O H2	37 68	n.a.	n.a.	n.a.	[322]
1d		R=Et, Cy Y=CH2, 1,3‐phenyl	CO/H2O H2	85 [323] 26 [324]	ETM	exp.	CV	[ 323 , 324 ]
1e		l=2, 3; m=1, 2, 3; n=1, 2 R1=Et, Cy; R2=Ph, Mes X=H, MeCN	CO/H2O H2	97 39	ETM	prop.	n.a.	[325]
2		L=MeCN, Cl, Br; n=1, 2 R1=H, Br, OMe, CO2(CH2)4OH; R2=H R2∩R2=Ph, pyr, phenanthrene R3=Bu, CH2PyMe+, propylNMe3 +, propylPEt3 +, propylPPh3 +, CH2C6H4PPh3 +	CO H2	52 [326] 100 [326]	ETM	comp.	DFT	[305, 317, 326, 327]
3	[PdL2Cl2]	L=pyrazole, 4‐methylpyridine, 3‐methylpyrazole	HCO2 − H2	20 54	ETM	prop.	n.a.	[328]
4a	[Pd(PPh3)2L]+	R1= –, H, OH; R2= –, Me, OH; Y=C, N	CO/H2O HCO2 −	75 45	ETM	prop.	n.a.	[255]
4b	[Pd(PPh3)2L]2+	L=4,4′‐dimethyl‐2,2′‐bpy, 4‐methyl‐1,10‐phen	CO/H2O HCO2 −	81 40	ETM	prop.	n.a.	[255]
5	[Pt(dmpe)2]2+	dmpe=1,2‐bis(dimethyl‐ phosphino)ethane	HCO2 −	90 [318]	ETH	exp. [329]	CV, NMR	[ 318 , 329 ]

[a] TMB=trimethoxybenzyl.