Stabilization and activation of Pd nanoparticles for efficient CO2-reduction: Importance of their generation within supramolecular network of tridentate Schiff-base ligands with N,N coordination sites

Discrete, Cationic Palladium(II)‐Oxo Clusters via f‐Metal Ion Incorporation and their Macrocyclic Host‐Guest Interactions with Sulfonatocalixarenes

“…The presence of the cacodylate caps and the ceria and thoria‐type components render the two cationic clusters Pd 6 Ce 8 and Pd 6 Th 8 electrochemically inert, unless more negative potentials are applied. However, the Pd II ions eventually undergo irreversible reduction during a voltammetric negative potential scan to form metallic palladium [37] (at −0.2 V, as demonstrated for Pd 6 Ce 8 , Figure S16). The generated Pd 0 sites are expected to behave similarly to Pt and induce redox transitions [38, 39] of otherwise highly‐inert arsenic oxo species (Figure S17).…”

“…Furthermore, due to the presence of interstitial Pd 0 sites, both pre‐reduced Pd 6 Ce 8 and Pd 6 Th 8 exhibit electrocatalytic activity toward CO 2 ‐reduction [37, 41–43] in the semi‐neutral medium of 0.1 mol dm −3 phosphate buffer of pH 6.1. Simply judging from the appearance of the well‐defined and sound CO 2 ‐reduction peak at the less negative (than typically reported) [37, 41, 42] potential of −0.3 V (Figure 4C) for the pre‐reduced Pd 6 Ce 8 , it can be considered as a potent electrocatalyst for the reduction of CO 2 . It is likely that the self‐poisoning (with CO) of Pd surfaces becomes less pronounced in such nanoengineered ceria‐encapulated Pd clusters.…”

“…Furthermore, due to the presence of interstitial Pd 0 sites, both pre-reduced Pd 6 Ce 8 and Pd 6 Th 8 exhibit electrocatalytic activity toward CO 2 -reduction [37,[41][42][43] in the semi-neutral medium of 0.1 mol dm À 3 phosphate buffer of pH 6.1. Simply judging from the appearance of the well-defined and sound CO 2 -reduction peak at the less negative (than typically reported) [37,41,42] potential of À 0.3 V Table 1: Association constants (K a ) of cationic mixed-oxo clusters with CXn and thermodynamic parameters for complex formation (kcal mol À 1 ). [a] Host Guest K a [× 10…”

Discrete, Cationic Palladium(II)‐Oxo Clusters via f‐Metal Ion Incorporation and their Macrocyclic Host‐Guest Interactions with Sulfonatocalixarenes

“…Furthermore, due to the presence of interstitial Pd 0 sites, both pre-reduced Pd 6 Ce 8 and Pd 6 Th 8 exhibit electrocatalytic activity toward CO 2 -reduction [37,[41][42][43] in the semi-neutral medium of 0.1 mol dm À 3 phosphate buffer of pH 6.1. Simply judging from the appearance of the well-defined and sound CO 2 -reduction peak at the less negative (than typically reported) [37,41,42] potential of À 0.3 V Table 1: Association constants (K a ) of cationic mixed-oxo clusters with CXn and thermodynamic parameters for complex formation (kcal mol À 1 ). [a] Host Guest K a [× 10 (Figure 4C) for the pre-reduced Pd 6 Ce 8 , it can be considered as a potent electrocatalyst for the reduction of CO 2 .…”

“…It is likely that the self‐poisoning (with CO) of Pd surfaces becomes less pronounced in such nanoengineered ceria‐encapulated Pd clusters. Based on chromatographic analysis performed as described earlier, [37] carbon monoxide and hydrogen (i.e. syngas components) are the main reaction products.…”