Electrochemical reduction of CO2 to synthesis gas with controlled CO/H2 ratios

• Published in: Energy & environmental science 2017, Vol.10 (5), p.1180-1185
• Main Authors: Sheng, Wenchao, Kattel, Shyam, Yao, Siyu, Yan, Binhang, Liang, Zhixiu, Hawxhurst, Christopher J, Wu, Qiyuan, Chen, Jingguang G
• Format: Article
• Language: English
• Subjects: Absorption spectroscopy; Aqueous electrolytes; Beta phase; Carbon; Carbon dioxide; Carbon monoxide; Chemical reduction; Density functional theory; Electrocatalysts; Electrochemistry; Methyl alcohol; Nanoparticles; Palladium; Reduction (electrolytic); Searching; Synthesis gas; X ray absorption; X-ray absorption spectroscopy; X-ray diffraction
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/c7ee00071e

The electrochemical carbon dioxide reduction reaction (CO2RR) to simultaneously produce carbon monoxide (CO) and hydrogen (H2) has been achieved on carbon supported palladium (Pd/C) nanoparticles in an aqueous electrolyte. The synthesis gas product has a CO to H2 ratio between 0.5 and 1, which is in the desirable range for thermochemical synthesis of methanol and Fischer-Tropsch reactions using existing industrial processes. In situ X-ray absorption spectroscopy in both near-edge (XANES) and extended regions (EXAFS) and in situ X-ray diffraction show that Pd has transformed into beta -phase palladium hydride ( beta -PdH) during the CO2RR. Density functional theory (DFT) calculations demonstrate that the binding energies of both adsorbed CO and H are significantly weakened on PdH than on Pd surfaces, and that these energies are potential descriptors to facilitate the search for more efficient electrocatalysts for syngas production through the CO2RR.