Porous Indium Nanocrystals on Conductive Carbon Nanotube Networks for High‐Performance CO₂‐to‐Formate Electrocatalytic Conversion

Abstract

Ever‐increasing emissions of anthropogenic carbon dioxide (CO2) cause global environmental and climate challenges. Inspired by biological photosynthesis, developing effective strategies NeuNlto up‐cycle CO2 into high‐value organics is crucial. Electrochemical CO2 reduction reaction (CO2RR) is highly promising to convert CO2 into economically viable carbon‐based chemicals or fuels under mild process conditions. Herein, mesoporous indium supported on multi‐walled carbon nanotubes (mp‐In@MWCNTs) is synthesized via a facile wet chemical method. The mp‐In@MWCNTs electrocatalysts exhibit high CO2RR performance in reducing CO2 into formate. An outstanding activity (current density −78.5 mA cm−2), high conversion efficiency (Faradaic efficiency of formate over 90%), and persistent stability (~30 h) for selective CO2‐to‐formate conversion are observed. The outstanding CO2RR process performance is attributed to the unique structures with mesoporous surfaces and a conductive network, which promote the adsorption and desorption of reactants and intermediates while improving electron transfer. These findings provide guiding principles for synthesizing conductive metal‐based electrocatalysts for high‐performance CO2 conversion.

In Situ Reconstruction of Scalable Amorphous Indium-Based Metal–Organic Framework for CO2 Electroreduction to Formate over an Ultrawide Potential Window

“…Notably, aMIL-68­(In)-NH 2 exhibited high FE HCOO – values (>90%) over a wide potential window of 800 mV (−0.6 V to −1.4 V vs RHE), which outperformed most reported electrocatalysts such as In 2 O 3– x @C (700 mV), Bi 2 O 3 /BiO 2 (600 mV), and MIL-68­(In)-NH 2 (300 mV) (Figure c and Table S1). ,,− In addition, the maximum FE HCOO – reached 92.9% at −1.0 V vs RHE, substantially exceeding cMIL-68­(In) (81.5%) and aMIL-68­(In) (84.6%) (Figure d). It was noted that the FE HCOO – on aMIL-68­(In)-NH 2 also retained above 90% at wide applied current densities from 50 to 250 mA cm –2 (Figure S8).…”

“…The FE HCOO – values consistently maintained above 90%, meanwhile the current density remained approximately at −129.9 mA cm –2 throughout a continuous reaction for 22 h. The results outperformed most of the reported studies such as In 2 O 3 -NC@GO (−40.38 mA cm –2 , 91.2%, and 10 h), In-SSZ-13­(MP) (−133.3 mA cm –2 , 92%, and 5 h), and InOOH (−151 mA cm –2 , 86.5%, and 5.5 h) (Figure g and Table S2). ,,,,,,− Considering the excellent CO 2 reduction performances of aMIL-68­(In)-NH 2 , laboratory-scale production trials were carried out. As shown in Figure h, up to 16 g of aMIL-68­(In)-NH 2 catalyst could be easily prepared in one batch using a 1000 mL beaker in 20 h. The XRD pattern of scale-produced aMIL-68­(In)-NH 2 was consistent with that of aMIL-68­(In)-NH 2 (Figure S11a).…”

Recent research progresses of Sn/Bi/In‐based electrocatalysts for electroreduction CO2 to formate

“…(Figure 11a). [56] The mp‐In@MWCNTs had large surface areas and developed a conductive network, which allowed for the transport of electrons and enhanced catalytic activity. As a result, with a high current density of 78.5 mA cm −2 , mp‐In@MWCNTs electrocatalysts demonstrated remarkable performance during CO 2 RR due to their distinctive electronic architectures with mesoporous surfaces and a conductive network.…”

Gallium–indium bimetal sites in the indium–gallium metal organic framework for efficient electrocatalytic reduction of carbon dioxide into formate

“…Recently, indium (In)-based materials, with weak metal–hydrogen bonds, are found to be desirable for efficiently converting CO 2 into formate by inhibiting the competitive hydrogen evolution reaction. 12–15 In particular, the indium metal organic framework (InMOF) catalyst, with high surface area, porous structure, and abundant unsaturated metal sites, is found to be advantageous for use in the eCO 2 RR field. However, achieving high selectivity of formate on InMOF catalysts often requires a high overpotential, and effectively suppressing the production of CO remains a challenge.…”