Coupling EC CO2 reduction on PhC2Cu-gas diffusion electrode with PEC glycerol oxidation on AuCu/TiO2HNTAs

Abstract

The coupling of electrocatalytic (EC) CO₂ reduction with value-added oxidation reactions has attracted considerable attention owing to its significance in alleviating environmental and energy issues. Here, we constructed a copper phenylacetylide (PhC₂Cu)-based gas diffusion electrode and applied it in the EC CO₂RR for the first time. We also engineered AuCu-loaded TiO₂ hierarchical nanotube arrays (AuCu/TiO₂HNTAs) for photoelectocatalytic (PEC) glycerol oxidation. Results showed that 10 wt% PhC₂Cu achieved a 1 : 1 H₂/CO product as syngas at −0.7 V vs. RHE. The AuCu loading dramatically enhanced the catalyst performance. A photocurrent density >0.6 mA cm⁻² was obtained with 0.05 wt% AuCu₄ in the presence of 0.01 M glycerol, which was much higher than those of pure TiO₂HNTAs and their monometallic counterparts. Ethanol and CO₂ were the products in the anodic chamber, the latter of which could potentially be used as a reactant in the cathode chamber. The prepared cathode and anode work well in the overall reaction system.