Electrochemical promotion of copper nanoparticles for the reverse water gas shift reaction

Abstract

Electrochemical promotion of catalysis (EPOC) is one of the promising ways to in-situ control and enhance catalytic processes of the reverse water gas shift reaction (RWGS), which recycles carbon dioxide...

Insight into Electrochemical Promotion of Cu/Co3O4 Catalysts for the Reverse Water Gas Shift Reaction

“…For instance, the stability and dispersion of Cu NPs after catalytic reactions were improved by supporting on Co 3 O 4 , as shown in SEM images, which prevented Cu from deactivation caused by agglomeration and sintering that easily happened at high temperatures. [26] Conversely, considering that Co 3 O 4 acted as a semiconductor which only showed electrical conductivity above 350 °C, [36,51] it was necessary to modify Co 3 O 4 by loading conductive Cu NPs to improve its conductivity and electrocatalytic properties before being used as an electrode in EPOC studies, which will be discussed later. Nevertheless, excessive As a result, 4 wt.% was taken as the optimum Cu loading on Co 3 O 4 , which maintained a high activity and stability and could be promoted after polarization.…”

“…In contrast, CV of spent sample changed significantly and showed two typical cathodic peaks, similar to that of as-prepared free-standing Cu deposited on YSZ, as shown in Figure 6c, which was consistent with the former study on Cu/YSZ. [26] During catalytic reactions, CuO phase that could store huge amounts of oxygen was formed by oxidizing Cu with O 2À supplied from YSZ and CoO x under positive polarization. In this case, Co stayed at reduced state The rapid increase of currents at higher potentials (> 1.0 V) in CVs represented oxygen evolution reaction (OER), as shown in Eq.…”

“…Moreover, the N G of 4 wt.% Cu/Co 3 O 4 under stoichiometric condition at + 2 V and 400 °C was 1.3 × 10 À 7 mol, 30 % higher than that of free-standing Cu under the same condition, which was 1.0 × 10 À 7 mol. [26] The increased value of N G was attributed to the existence of Co 3 O 4 , which had a huge oxygen capacity and could provide/receive O 2À .…”

“…The Cu NPs were synthesized using the polyol method following the same procedures as reported earlier [26] and stored in colloidal solution (1 mg mL…”

“…[28,29] A recent EPOC study on free-standing Cu deposited on YSZ (Cu/ YSZ) illustrated the possibility of promoting RWGS catalytic rate by in-situ controlling the oxidation states of Cu NPs. [26] Since copper is prone to oxidation [30] and sintering at high temperatures, [31,32] selecting suitable oxides to induce MSI effect is considered a practical method to improve thermal stability and dispersion of Cu NPs. [33] Cobalt oxide (Co 3 O 4 ) is a conducting metal oxide [34] and has the high oxygen storagerelease capacity.…”