Ligand and temperature effects of porous palladium nanoparticle ensembles with grain boundaries for highly efficient electrocatalytic CO2 reduction

Electrocatalytic conversion from carbon dioxide with main products of carbon monoxide and hydrogen provides an economic and sustainable pathway to produce syngas, while the involved electrocatalysts with high activity and stability as well as highly tunability for CO/H 2 ratio are still rare. Here, we report a facile method to prepare palladium (Pd) nanoparticle ensembles with unique three-dimentional (3D) architecture and porosity as well as plenty of grain boundaries, which are electrocatalytically active for electrochemical carbon dioxide reduction (eCO 2 RR) to syngas. At the potential of − 0.8 V (versus reversible hydrogen electrode), the CO selectivity of such Pd nanoparticle ensembles is up to ca. 90% and the CO/H 2 ratio can be adjusted from one to six by varying the applied potentials. The syngas production on Pd nanoparticle ensembles can be further regulated by changing the reaction temperature and modified ligands. This method for fabricating Pd nanoparticle ensembles with rational tenability paves the way for the fundamental research and commercial deployment of eCO 2 RR and syngas production. Graphical abstract Pd nanoparticle ensembles with grain boundaries and high porosity were developed for tunable CO 2 conversion to syngas under ligand exchange and temperature control.