Potential- and Time-Dependent Dynamic Nature of an Oxide-Derived PdIn Nanocatalyst during Electrochemical CO 2 Reduction.

Electrochemical reduction of CO 2 into valuable fuels and chemicals is a promising route of replacing fossil fuels by reducing CO 2 emissions and minimizing its adverse effects on the climate. Tremendous efforts have been carried out for designing efficient catalyst materials to selectively produce the desired product in high yield from CO 2 by the electrochemical process. In this work, a strategy is reported to enhance the electrochemical CO 2 reduction reaction (ECO 2 RR) by constructing an interface between a metal-based alloy (PdIn) nanoparticle and an oxide (In 2 O 3 ), which was synthesized by a facile solution method. The oxide-derived PdIn surface has shown excellent eCO 2 RR activity and enhanced CO selectivity with a Faradaic efficiency (FE) of 92.13% at -0.9 V (vs RHE). On the other hand, surface PdO formation due to charge transfer on the bare PdIn alloy reduces the CO 2 RR activity. With the support of in situ (EXAFS and IR) and ex situ (XPS, Raman) spectroscopic techniques, the optimum presence of the Pd-In-O interface has been identified as a crucial parameter for enhancing eCO 2 RR toward CO in a reducing atmosphere. The influence of eCO 2 RR duration is reported to affect the overall performance by switching the product selectivity from H 2 (from water reduction) to CO (from eCO 2 RR) on the oxide-derived alloy surface. This work also succeeded in the multifold enhancement of the current density by employing the gas diffusion electrode (GDE) and optimizing its process parameters in a flow cell configuration.