Boosting Production of HCOOH from CO₂ Electroreduction via Bi/CeO_x

Abstract

Formic acid (HCOOH) is one of the most promising chemical fuels that can be produced through CO 2 electroreduction. However, most of the catalysts for CO 2 electroreduction to HCOOH in aqueous solution often suffer from low current density and limited production rate. Herein, we provide a bismuth/cerium oxide (Bi/CeO x) catalyst, which exhibits not only high current density (149 mA cm À2), but also unprecedented production rate (2600 mmol h À1 cm À2) with high Faradaic efficiency (FE, 92 %) for HCOOH generation in aqueous media. Furthermore, Bi/CeO x also shows favorable stability over 34 h. We hope this work could offer an attractive and promising strategy to develop efficient catalysts for CO 2 electroreduction with superior activity and desirable stability. Excessive CO 2 emission has brought about severe problems related to resources, environment, and climate. Thus, converting CO 2 into valuable chemical fuels attract more and more research attention. [1] Among the various conversion approaches, electrochemical reduction of CO 2 in aqueous media is more favorable because it can make better use of electricity generated from sustainable sources without producing any additional CO 2. [1-5] Nevertheless, low activity, selectivity and stability of catalysts are still the big challenges for CO 2 electroreduction. Therefore, developing efficient electrocatalysts for CO 2 reduction is highly desired. As one of the most attractive CO 2 reduction products, formic acid (HCOOH) is widely identified as a desirable hydrogen carrier. [6-10] Up to now, many metallic catalysts, including Cd, Hg, Pd, Pb, In, Sn and Bi are found to be effective to form HCOOH (or formate) through CO 2 electroreduction. [11-29] However, the activities are still very low even using the toxic or noble metals. As well as we know, the current density and production rate (in H-type reaction cell) by far are less than 80 mA cm À2 , and 1500 mmol h À1 cm À2 , respectively. [11-29] On the other side, high applied potentials and current density always lead to the low Faradaic efficiency (FE) due to the severe competitive hydrogen evolution reaction (HER). [25] Therefore, achieving a low-cost, eco

Active/Conductive Layer Stacked Superlattices for Highly Selective CO2 Electroreduction

“…Formate, which is widely used as most kinetically accessible feedstock in the eld of pharmaceutical, textile, and energy, is an attractive liquid product of CO 2 RR 3,6,7,8 . Metal oxides (such as SnO 2 , Bi 2 O 3 , In 2 O 3 ) as the most common and widely available catalysts have been extensively explored to achieve CO 2 electroreduction to formate with considerable activity 6,9,10,11,12,13,14 . The development of advanced in situ characterization uncovers that metal oxides can undergo in situ self-reduction to zerovalence metal during the CO 2 RR (Fig.…”

Boosting Electrochemical Carbon Dioxide Reduction on Atomically Dispersed Nickel Catalyst

“…These results reveal that the rate-determining step of ECO 2 R on Ni–N sites for NiNx-600 is the proton-coupled electron transfer step to form the *COOH intermediate ( Kong et al, 2021 ) as its Tafel slope is close to 118 mV dec −1 . Notably, the markedly lower Tafel slope of NiNx-600 indicates enhanced reaction kinetics in the ECO 2 R process compared to the other counterparts ( Duan et al, 2021 ). The Nyquist plots were acquired from electrochemical impedance spectroscopy (EIS) measurements.…”

Penta‐coordinated Al3+ Stabilized Defect‐Rich Ceria on Al2O3 Supported Palladium Catalysts for Lean Methane Oxidation

“…As illustrated in Figure 1, the activated RAl 2 O 3 showed a typical γ−Al 2 O 3 crystal structure (JCPDS), [5e,16] indicating that the reduction process did not alter the surface crystalline phases. For hybrid RAl 2 O 3 −CeO 2 support, the characteristic peaks at 28.5°, 47.5° and 56.2° can be ascribed to the cubic structure of CeO 2 [17] . The XRD pattern of 1.0Pd/RAl 2 O 3 has distinct standard diffraction peaks corresponding to PdO phase (2θ=33.9°, 42.1°), resulting from large metal nanoparticles [18] .…”