Affiliation:
1. Center of Advanced Nanocatalysis (CAN) Department of Applied Chemistry Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Hefei Anhui 230026 P. R. China
2. Department of Chemistry Laboratory of Nanomaterials for Energy Conversion (LNEC) University of Science and Technology of China Hefei Anhui 230026 P. R. China
Abstract
AbstractConstructing the pore structures in amorphous metal oxide nanosheets can enhance their electrocatalytic performance by efficiently increasing specific surface areas and facilitating mass transport in electrocatalysis. However, the accurate synthesis for porous amorphous metal oxide nanosheets remains a challenge. Herein, a facile nitrate‐assisted oxidation strategy is reported for synthesizing amorphous mesoporous iridium oxide nanomeshes (a‐m IrOx NMs) with a pore size of ∼4 nm. X‐ray absorption characterizations indicate that a‐m IrOx NMs possess stretched Ir─O bonds and weaker Ir–O interaction compared with commercial IrO2. Combining thermogravimetric‐fourier transform infrared spectroscopy with differential scanning calorimetry measurements, it is demonstrated that sodium nitrate, acting as an oxidizing agent, is conducive to the formation of amorphous nanosheets, while the NO2 produced by the in situ decomposition of nitrates facilitates the generation of pores within the nanomeshes. As an anode electrocatalyst in proton exchange membrane water electrolyzer, a‐m IrOx NMs exhibit superior performance, maintaining a cell voltage of 1.67 V at 1 A cm−2 for 120 h without obvious decay with a low loading (0.4 mgcatalyst cm−2). Furthermore, the nitrate‐assisted method is demonstrated to be a general approach to prepare various amorphous metal oxide nanomeshes, including amorphous RhOx, TiOx, ZrOx, AlOx, and HfOx nanomeshes.
Funder
National Key Research and Development Program of China
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Natural Science Foundation of Anhui Province
Anhui Provincial Development and Reform Commission
Youth Innovation Promotion Association of the Chinese Academy of Sciences