Enhancing Activity and Reducing Cost for Electrochemical Reduction of CO₂ by Supporting Palladium on Metal Carbides

Abstract

Electrochemical CO 2 reduction reaction (CO 2 RR) with renewable electricity is apotentially sustainable method to reduce CO 2 emissions.P alladium supported on cost-effective transition-metal carbides (TMCs) are studied to reduce the Pd usage and tune the activity and selectivity of the CO 2 RR to produce synthesis gas,using acombined approach of studying thin films and practical powder catalysts,i nsitu characterization, and density functional theory (DFT) calculations. Notably,Pd/TaC exhibits higher CO 2 RR activity,stability and CO Faradaic efficiency than those of commercial Pd/C while significantly reducing the Pd loading. In situ measurements confirm the transformation of Pd into hydride (PdH) under the CO 2 RR environment. DFT calculations reveal that the TMC substrates modify the binding energies of key intermediates on supported PdH. This work suggests the prospect of using TMCs as low-cost and stable substrates to support and modify Pd for enhanced CO 2 RR activity.

Boosting Activity and Selectivity of CO2 Electroreduction by Pre‐Hydridizing Pd Nanocubes

“…[6][7][8] Instead of suppressing HER, combining the CO 2 RR and HER together has been considered as a viable approach, which produces syngas (CO and H 2 ) with tunable CO/H 2 molar ratios that can be readily used to manufacture valueadded chemicals using exiting thermochemical processes, such as the Fischer-Tropsch and methanol synthesis reactions. [9][10][11][12] Palladium (Pd) has been identified as a potential candidate for the production of syngas via CO 2 RR. [9,[13][14][15][16][17] While Pd itself is a good HER catalyst, it was considered to be unsuitable for CO…”

“…[ 6–8 ] Instead of suppressing HER, combining the CO 2 RR and HER together has been considered as a viable approach, which produces syngas (CO and H 2 ) with tunable CO/H 2 molar ratios that can be readily used to manufacture value‐added chemicals using exiting thermochemical processes, such as the Fischer–Tropsch and methanol synthesis reactions. [ 9–12 ]…”

“…[9] Moreover, the CO/H 2 ratio can be further improved by using Pd-based bimetallic catalysts and/ or supporting Pd on metal carbides and nitrides. [11,13,19] The key to tune the CO/H 2 ratio over Pd-based electrocatalyst is to control the formation of the PdH 1 phase, specifically, the hydride formation potentials during the CO 2 RR. Lee et al found that by alloying with first-row transition metals, the hydride formation potentials of PdM (M = Cu, Ni) were cathodically shifted, enabling the syngas production with the CO/H 2 ratios between 1 and 2 at 0.9 V (versus reversible hydrogen electrode or RHE).…”

Microenvironment Engineering for the Electrocatalytic CO2 Reduction Reaction

“…The MBSs mainly include metal nanoparticles (Figure 5h), [68] oxides (Figure 5i), [69] carbides (Figure 5j), [62j, 64a,d] alloy particles (Figure 5k), [70] and nitrides, [63, 64e] which allow the formation of more active sites via the introduction of heterojunction interfaces [64e] and resist the poisoning of metal catalysts by the CO intermediate (Figure 5). [64b] For instance, Wu's group developed a solid–liquid phase transition method to disperse Sn or In single atoms within the framework constructed by Ga nanoparticles (Figure 5h) [68] .…”

Amorphization‐Activated Copper Indium Core‐Shell Nanoparticles for Stable Syngas Production from Electrochemical CO2 Reduction

“…CO 2 is a completely oxidized and very stable molecule that needs appropriate catalysts to promote its chemical conversion to minimize the energy loss during the CO 2 RR. Among them, the conversion of CO 2 to CO by noble metal catalysts has been widely studied by researchers around the world, such as Au, Ag, and Pd, due to their high selectivity, good catalytic activity, and stability [24–28] . However, low reserves and high prices severely limit their practical application.…”