Porous Palladium Nanomeshes with Enhanced Electrochemical CO2 -into-Syngas Conversion over a Wider Applied Potential.

Abstract

Electrochemical conversion of CO2 into syngas, which can be used directly in the classical petroleum industrial processes, provides a powerful approach for achieving the recycling of anthropogenic carbon. Pd has previously been reported to be capable of converting CO2 into syngas with various CO/H2 ratios, but only at limited applied potential, which is mainly attributed to fewer active sites exposed toward electrocatalysis. Herein, high-performance Pd nanomeshes (NMs) assembled with branch-like Pd nanoparticles were designed and synthesized by using a simple interface-induced self-assembly strategy; these NMs could catalyze CO2 -into-syngas conversion with a high current density in a wide applied potential range from -0.5 to -1.0 V (vs. reversible hydrogen electrode). Further evidence validated that the enhanced activity of the Pd NMs was not only caused by the crosslinked network structure accelerating electron transport, but also by the greater number of edge and/or corner active sites exposed on the surface of the NMs, which facilitated CO2 adsorption, CO2 .- formation, COOH* stabilization, and CO generation. Under optimal operating conditions, Pd NMs could balance two competing reactions: CO2 reduction and hydrogen evolution. The resultant syngases with the ideal and tunable CO/H2 ratio between 0.5:1 and 1:1 could be used directly for methanol synthesis and Fischer-Tropsch reactions.