High Performance 3D Self‐Supporting Cu−Bi Aerogels for Electrocatalytic Reduction of CO₂ to Formate

Abstract

The electrocatalytic reduction of CO 2 (CO 2 RR) to CO, formate, methane, and other high-value compounds is a promising technique. However, current electrocatalysts suffer from drawbacks such as few active catalytic sites, poor selectivity and low stability, etc, which restrict the practical application. Although monatomic metal catalysts have been widely reported in recent years, high performance non-noble metal aerogels were rarely investigated for electrocatalytic CO 2 RR. Herein, CuÀ Bi aerogels with boosted CO 2 RR activity were well constructed by a simple one-step self-assembly method. The resultant Cu 1 Bi 2 exhibits excellent CO 2 RR activity with high faradaic efficiency (FE) of 96.57 % towards HCOOH at a potential of À 0.9 V vs. RHE, and the FE HCOOH remains over 80.18 % in a wide potential window (À 0.8 V to À 1.2 V vs. RHE). It demonstrated that the enhanced CO 2 RR activity of CuÀ Bi aerogels could be attributed to the 3D self-supporting structure of the catalysis, synergistic effect, and low interfacial charge transfer resistance.

Synthesis of AuX (X = Ni, Ga, Mo, Zn, and Cr) Alloy Aerogels as High-Performance Electrocatalytic CO2 Reduction Reaction Catalysts

“…The AuX alloy aerogels were synthesized with metal precursors of Au and X (X = Ga, Ni, Mo, Zn, Cr) in the presence of NaBH 4 as the reducing agent. Notably, the self-assembly process of the AuX hydrogels was obtained by standing for 3 h at 60 °C, which is shorter than the recently reported metal aerogels. − Then, the hydrogels were dried by a freeze-drying method to obtain three-dimensional porous metal aerogels. Finally, the AuX aerogels were dripped onto carbon paper to serve as the working electrodes for the electroreduction of CO 2 .…”

Metal‐Based Aerogels Catalysts for Electrocatalytic CO2 Reduction

“…In this regard, effective strategies to ensure uneven catalyst surfaces, such as arranging specific atomic structures or mixing multiple elements, should be considered (Tables 2 and 3). Single-metal aerogel Au CO 2 !CO 95.6 %, À 0.5 V vs. RHE À 15.10 mA cm À 2 ; À 0.59 V vs. RHE [138] Multi-metal-doped aerogel AgÀ Cu CO 2 !CO 89.4 %, À 0.89 V vs. RHE À 5.86 mA cm À 2 ; À 0.89 V vs. RHE [67] CuÀ Bi CO 2 !HCOOH 96.57 %, À 0.90 V vs. RHE À 10.72 mA cm À 2 ; À 0.90 V vs. RHE [113] BiÀ Sn CO 2 !HCOOH 93.9 %, À 1.00 V vs. RHE À 9.30 mA cm À 2 ; À 1.00 V vs. RHE [68] PdÀ Cu CO 2 !CH 3 OH 80.0 %, À 2.10 V vs. Ag/Ag + À 31.80 mA cm À 2 ; À 2.10 V vs. Ag/Ag + [99] Au-Pd CO 2 !CO 99.96 %, À 0.50 V vs. RHE Not reported [139] NÀ P-Co CO 2 !CO 99.1 %, À 2.40 V vs. Ag/Ag + À 143.60 mA cm À 2 ; À 2.40 V vs. RHE [140] Nano-metal-doped carbon aerogel Cu-Ag CO 2 !CO 71.00 %, À 1.26 V vs. RHE À 15.77 mA cm À 2 ; À 1.26 V vs. RHE [141] Cu NPs CO 2 !CO 75.60 %, À 0.60 V vs. RHE À 5.00 mA cm À 2 ; À 0.60 V vs. RHE [142] Ni-N CO 2 !CO 98.00 %, À 0.80 V vs. RHE À 15.16 mA cm À 2 ; À 1.00 V vs. RHE [126] Ni-N CO 2 !CO 90.20 %, À 0.80 V vs. RHE Not reported [143] Chemistry-A European Journal 1) Among single non-precious metals, Zn is the most promising economic catalyst for the production of CO and is an abundant transition metal on Earth. [128] Although Zn is less active than Au or Ag in making CO, recent reports suggest that its activity can be enhanced by materials engineering, such as nanostructuring, preparation of Zn-based compounds, and combination with other materials.…”

“…This is mainly due to the existence of CuBiO 4 crystals in CuBi aerogels, which also proves that the synergistic effect of CuBi improves the electrocatalytic activity of aerogels for CO 2 . After 36 h of continuous catalysis, the TEM images show that the catalyst still maintains a self‐supporting porous structure, indicating the excellent structural stability of CuBi aerogels (Figure 5e, f) [113] …”

“…After 36 h of continuous catalysis, the TEM images show that the catalyst still maintains a self-supporting porous structure, indicating the excellent structural stability of CuBi aerogels (Figure 5e, f). [113] Wu et al mixed Bi(NO 3 ) 3 , SnCl 2 and NaBH 4 at 60 °C for 12 h, and then freeze-dried BiSn aerogels composed entirely of nontransition metal elements for the first time. Compared with single Bi or Sn aerogel, the BiSn aerogel exposes more active sites, and the mass transfer performance is further enhanced, which endows a Faraday efficiency of 93.9 % of HCOOH.…”

Electro‐Synthesis of Organic Compounds with Heterogeneous Catalysis

“…Li et al prepared Cu/Bi aerogels with enhanced eCO 2 RR activity using a simple one‐step assembly method. [ 197 ] At a potential of −0.9 V versus RHE, the Cu 1 Bi 2 catalyst exhibits excellent eCO 2 RR activity with a FE of 96.57% towards HCOOH, and the FE of HCOOH remains over 80.18% over a wide potential range (−0.8 to −1.2 V vs RHE). The increased eCO 2 RR activity is due to the self‐supporting structure and synergistic effect of Cu and Bi.…”